Lightweight Structures

The main challenging issues of vehicles with electric propulsion are on the limited energy source due to relatively low battery capacity and low excitation of power traction. They can be tackled down by designing lightweight structures for frameworks and bodies of the vehicles. Composite materials which have a high strength to weight ratio are the best choice for designing and manufacturing the lightweight structures. A review of recent progress in utilization of the composite materials for electric vehicle structures is presented. It focuses on how the structures can support the electric vehicles to compete with internal combustion engine vehicles regarding their performance on the road. The utilization of composite material for structures of railway vehicles is also summarized. Furthermore, discussions are extended to the key technologies required for applying the composite materials in Indonesia such as composite–metal joint technology, fiber and matrix production technology, and...

ABSTRACT This article presents the analysis of the structure, energy and cost efficiency of three lightweight structural systems–wood light frames (WLF), lightweight steel frames (LGSF) and 3D sandwich (3DSP) panels–during their useful life. The structural systems focussed upon in this study are commonly used in Eastern Europe with specific reference to Turkey. The structural analysis and design was carried out using ETABS while EnergyPlus was used in the analysis of the energy consumption of the buildings. The results of the structural analysis of the three alternative construction systems show that 3DSP has better structural behaviour in terms of resistance against lateral loads. The thermal performance evaluation of the walls and ceilings shows that the WLF and LGSF walls have better insulation values (12.5% lower U-value) while the roof construction of the 3DSP has much better insulation performance (70% lower U-value). Moreover, the building designed with 3DSP requires 11% less energy for total heating and cooling during one year. The information for the building industry in Turkey shows that the cost of construction for 3DSP construction is 34.6% lower than for WLF and 27.7% lower than LGSF.

The increasing demand for energy efficient electric cars, in the automotive sector, entails the need for improvement of their structures, especially the chassis, because of its multifaceted role on the vehicle dynamic behaviour. The major criteria for the development of electric car chassis are the stiffness and strength enhancement subject to mass reduction as well as cost and time elimination. Towards this direction, this work indicates an integrated methodology of developing an electric car chassis considering the modeling and simulation concurrently. The chassis has been designed in compliance with the regulations of Shell Eco Marathon competition. This methodology is implemented both by the use of our chassis load calculator (CLC) model, which automatically calculates the total loads applied on the vehicle’s chassis and by the determination of a worst case stress scenario. Under this extreme stress scenario, the model’s output was evaluated for the chassis design and the FEA me...

The reuse of construction and demolition wastes, especially crushed clay bricks (CCB), represents a major contribution to the environment. Due to the nature of clay bricks, it can be considered as source of fine and coarse aggregate to produce structural lightweight concrete (LWC). In this paper, the clay brick is crushed into the sizes of fine and coarse aggregate for concrete aiming to produce structural lightweight concrete. On achieving the targeted concrete properties, the physical and mechanical properties of the obtained concrete are studied. The results indicated that lightweight concrete can be produced by utilizing CCB as coarse and fine aggregate. Limited combination of CCB and natural aggregate can yield structural LWC, which can be used in structural purposes. The attained LWC mixes have lower modulus of elasticity, higher permeability and lower strength than the corresponding control concrete mixes.

Increasing use of hydroforming in automotive applications requires intensive research and development on all aspects of this relatively
new technology to satisfy an ever-increasing demand by the industry. This paper summarizes a technological review of hydroforming
process from its early years to very recent dates on various topics such as material, tribology, equipment, tooling, etc., so that other
researcher at different parts of the world can use it for further investigations in this area.

Adaptive Architecture is a multidisciplinary field concerned with structures that are designed to adapt to their environments, their inhabitants, and objects as well as those structures that are entirely driven by human needs. This tendency has been encouraged by its multidisciplinary nature, developments across architecture, material technology, and the temporary technological structure research field. This paper aims to allow readers to take a step ahead advancing the exploration in technology and new design tools with thematic past and future links across this exciting, emerging field of lightweight structures in architecture with a particular focus on housing design. Concerning the potential of integrating live forms and structures to provide flexible, adaptable as well as transformable living spaces in contrary to massive and heavy materials which grant opportunity for permanent and safe living spaces. To this aim, it presents a cross-disciplinary framework of adaptive lightweight architecture that contains a reversible construction process rather than a linear design process and discussing the new method of work announcing our habitats by introducing the key interlinked components of the degree of adaptability of living space. This is followed by a brief outline of overarching strategies and a design proposal that can be employed in this context.

7000 series aluminum alloys have particularly high strength, if compared to other aluminum alloys or even to some high strength steels. Currently, this alloy is considered on the next developments of automotive structures, as an enabler of improved mechanical and safety properties, associated with weight reduction, supporting the industry to fulfill fuel economy and greenhouse gases emissions regulations. Due to the proneness to hot cracking and welding embrittlement, the joining of 7000 series sheets is limited to mechanical methods, such as self-piercing rivets.

In order to provide the automotive industry with more joining methods suitable for the proposed high strength aluminum alloy, the objective of this work is to validate the resistance spot welding process of the AW-7075 alloy. The work is split in two parts: the preliminary assessment of the suitability of current welding procedures, norms and respective parameters, where the process window, weld nugget quality and electrode life-time are evaluated. Then an innovative approach is investigated, where the use of an upslope welding schedule, CuAg0.1 electrode caps, increased force and lower overall electric resistance could successfully validate the application, attending manufacturing requirements regarding welding quality, electrode life-time and process window. The resultant microstructure characteristics were analyzed with metallographic micro-sections and the phases were determined with the electron backscattered diffraction technique.

... the contrary, the presence of sheathings has been taken into account in the evaluation of compressive ... [6] Landolfo R., Fiorino L., Della Corte G. Seismic behavior of ... Corte G., Landolfo R. Experimental tests on typical screw connections for cold-formed steel housing, Engineering ...

κ-Carbide (κ) in high aluminium (Al) steels is grown from austenite (γ) via γ → γ + κ or γ → α + κ (α represents ferrite), and is a lamellar structure. This work demonstrates that the formability of high Al lightweight steels is affected by the lattice misfit and interface shape between κ and matrix. The cold workability can be improved by either to change the steel chemical constitution or to implement an electro-thermo-mechanical process. For ferrite-matrix-based high Al steel, electric-current promotes the spheroidization and refinement of κ structure and reduces volume fraction of κ phase. This retards the crack nucleation and propagation, and hence improves the materials formability. The observation is caused by a direct effect of electric-current rather than side effects.

Sandwich panels are increasingly used in aircraft structures due to their high specific bending stiffness and hence excellent buckling stability. The objective of this work is to find rough sizing process of a composite sandwich panel incorporating multi-scale modelling techniques to substantiate structural capability of each level of test pyramid, and find a minimum number of tests required to validate the approaches. The numerical analysis of such hybrid structures by means of the finite element method (FEM) requires specific strategies regarding the degree of homogeneity of each component. The common modelling approach for solid laminate of carbon fibre reinforced plastics (CFRP) structures using an extended layered shell element formulation can also be applied in modelling of sandwich panels in the global FE-model. The sandwich core, which is thicker compared to the solid laminate CFRP skins, can be formulated as an additional layer between the two face skin layers. For more detailed modelling of the sandwich structure, e.g. a cut out of the global FE model (GFEM), a solid shell approach can be applied. Both of the monolithic skins are idealised using layered shell, while the sandwich core is represented by solid elements. For a hard foam core the solid elements are assigned to the core system according to their type, isotropic material for unreinforced foam or homogenised, anisotropic properties for a reinforced foam core system. The homogenised mechanical properties of the reinforced foam core can be determined using analytical or numerical approaches, in which for a numerical approach the textile profile or needles shaped foam reinforcements are modelled with shell and beam elements respectively. With some modifications the meso-mechanical FE-model can further be used e.g. through the application of explicit FEM for the determination of an impact damage or using the virtual crack closure technique (VCCT) method and a higher level of FE discretisation to assess the growth behaviour of damages. The non-linear FE analyses show a good agreement with the recorded panel deformations.

Basis of this paper is to give a short brief insight into the current technical status of lightweight constructed vehicle with electric drive. Focus will specifically set on the design conditions and requirements of the carrier or body structure of e-cars.

Car body design in view of structural performance and lightweighting is a challenging task due to all the performance targets that must be satisfied such as vehicle safety and ride quality. In this paper, material replacement along with multidisciplinary design optimization strategy is proposed to develop a lightweight car body structure that satisfies the crash and vibration criteria while minimizing weight. Through finite element simulations, full frontal, offset frontal, and side crashes of a full car model are evaluated for peak acceleration, intrusion distance, and the internal energy absorbed by the structural parts. In addition, the first three fundamental natural frequencies are combined with the crash metrics to form the design constraints. The wall thicknesses of twenty-two parts are considered as the design variables. Latin Hypercube Sampling is used to sample the design space, while Radial Basis Function methodology is used to develop surrogate models for the selected crash responses at multiple sites as well as the first three fundamental natural frequencies. A nonlinear surrogate-based optimization problem is formulated for mass minimization under crash and vibration constraints. Using Sequential Quadratic Programming, the design optimization problem is solved with the results verified by finite element simulations. The performance of the optimum design with magnesium parts shows significant weight reduction and better performance compared to the baseline design.

So far, composite bridges have basically followed the forms acquired from the engineering practice in other materials, like steel. This was indeed a proper approach in the introduction stage of composite bridges. The best way to win customer’s confidence was then to copy the shapes and sections well-tested in other materials. Therefore we usually see composite Ibeams, channels, box girders, deck grids etc. that resemble the conventional steel components. Now the customer’s confidence is growing, it is time to review this strategy and to ask which shapes are appropriate for the best performances of composites in bridge structures. This paper presents some considerations concerning the shape selection of composite bridges. Attention has been paid to the shapes of entire bridges as well as their components, such as decks, girders, crossbeams etc. In particular, the anisotropic nature of composite materials and their relatively flexible technology offer the possibility to apply shapes of double curvature, smooth transitions, less fatigue sensitivity, high strength properties in the areas of stress peaks etc. Some new shape ideas for composite bridges have globally been sketched and discussed. The paper represents a view of a structural engineer rather than a composite technologist. The presented suggestions have, however, been discussed with some technologists. The intention is to continue this discussion, because the combination of both disciplines’ know-how can be seen as a precondition for successful composite application in bridge projects.

This paper gives a brief overview of sandwih application history in general and present composite sandwich structures at Airbus. Current R&D developments for sandwich in primary structure s are being outlined followed by a discussion of potentials and challenges for composite sandwich structures.

► A kind of Elastic Composite, Reinforced Lightweight Concrete (ECRL.C) with the mentioned specifics is a type of "Resilient Composite Systems (RCS)" in which, contrary to the basic geometrical assumption of the flexure theory in Solid Mechanics, "the strain changes in the beam height during bending" is typically "Nonlinear". (The RCS could be counted as "The Methodically Reinforced Nonlinear Porous Materials", also having the high specific modulus of resilience in flexure.)

♦ Through employing this integrated structure, with significantly high strain capability and modulus of resilience in bending, we can achieve the high bearing capacities in beams with the secure fracture pattern, in less weight.

♦ Due to the system particulars and its behavior in bending, the usual calculation of the necessary equilibrium steel amount to attain the low-steel bending sections with the secure fracture pattern in the beams and its related limitations do not become propounded. Thereby, the strategic deadlock of the high possibility of the brittle fracture pattern in the bending elements made of the usual reinforced lightweight concretes, especially about the low-thickness bending elements as slabs, is unlocked.

♦ This simple, applied technology and the related components and systems can have several applications in the road and building industries. (It can also be used in making the resilient pieces and constructions "with appropriate behavior and high resistance against severe blasts and shocks.)

♦ Regarding the "strategic importance of Lightweight and Integrated Construction in the practical increase of the resistance and safety against earthquake" and considering the appropriate behavior of this "resilient", durable structure against the dynamic loads, shakes, impacts, blasts, and shocks and the possibility of making some lightweight and insulating, non-brittle, reinforced sandwich panels and pieces, this resilient system and its components can especially be useful in the "seismic areas".

♦ This system can also be employed in constructing the vibration and impact absorber bearing pieces & slabs, which can be used in the "Railroad & Subway Structures" too.

♦ Here, the "Resilient Composite Systems (RCS)" and particularly, the ECRLC as a type of the RCS have been concisely presented. [By the way, an instance of the said new structure and its components and the results of some performed experiments (as bending loading and compressive loading of the slabs made of this structure, similar to ASTM E 72 Standard) have been shown in the related pictures & figures.]
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/ ● Key Words: Strength of materials (solid mechanics), Civil (construction), Materials, Earthquake (resistance and safety), Resilient concrete (flexible concrete, bendable concrete, elastic concrete), Composite concrete, Lightweight concrete, Reinforced concrete, Fibered concrete, Lightweight and integrated construction, Rail (railroad, railway), Subway, Road, Bridge, Resilience, Energy absorption, Fracture pattern, Non-linear, Strain changes, Beam, Ductility, Toughness, Insulating (insulation), Thin, Slab, Roof, Ceiling, Wall (partition), Building, Tower, Plan of mixture, Insulating reinforced lightweight pieces, 3d, Sandwich panel, Dry mix, Plaster, Foam, Expanded polystyrene (EPS), Polypropylene, Pozzolan, Porous matrix (Pored matrix), Mesh (lattice), Cement, RCS, ECRLC
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/ ► Contents:
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* ABSTRACT
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* I. INTRODUCTION
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* II. WHAT ARE THE RESILIENT COMPOSITE SYSTEMS
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- A. General Review
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- B. Components
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. - 1) Mesh or Lattice
. - 2) Fibers or Strands
. - 3) "Matrix" With the Suitable Hollow "Pores (Voids)" and/or "Lightweight Aggregates" in its Context
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- C. More Explanations About the RCS
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- D. Why Are These Systems Called "Composite"?
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- E. The General Structural Particulars and Functional Criteria as the Necessary Specifications of the Compound Materials Generally Called "Resilient Composite Systems"
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. - 1) General Structural Criteria
. - 2) Functional Criteria (Required Specifications)
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* III. "ELASTIC COMPOSITE REINFORCED LIGHTWEIGHT CONCRETE (ECRLC)" AS A TYPE OF THE RESILIENT COMPOSITE SYSTEMS (RCS)
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- An Instance of the Lightweight Concrete That Could be Used in Making the ECRLC
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* IV. REVIEW OF SOME EXPERIMENTS, AND MORE DESCRIPTION ABOUT ECRLC
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* V. SUPPLEMENTARY ELEMENTS
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* VI. APPLICATIONS
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* VII. FINAL REVIEW
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* ACKNOWLEDGEMENTS
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* REFERENCES 
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***
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/ ● General Review:
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• A kind of "Elastic Composite, Reinforced Lightweight Concrete" with the said specifics is a type of the "Resilient Composite Systems (R.C.S.)" in which, contrary to the basic geometrical assumption of flexure theory in the Solid Mechanics, the strain changes in the beam height during bending is typically "Non-linear".
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• Indeed, the RCS, as the Elastic Composite, Reinforced Lightweight Concrete (ECRLC), do not behave as most of the solid materials in bending.
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• In the "Resilient Composite Systems", distributed pores and/or appropriate lightweight aggregates or beads, accompanied by the reticular structure of the strengthened conjoined matrix, bring about the expedient internal shape changes during bending and continuing the elasticity in bending with the said nonlinearly pattern. This means better distribution of the stresses and strains and better utilizing the potential capacities of the employed reinforcements in bending and tension; whereas, in the usual lightweight concretes for instance, distributed hollow pores (such as the gas bulbs in the cellular concretes) or lightweight aggregates (such as Plastic, Rubber or polystyrene beads or any other kind of lightweight aggregates such as Perlite and Vermiculite) decrease the modulus of resilience in bending and could increase "the possibility of beam fracture of brittle and primary compressive type" in bending (compared to the concrete with higher density) according to the case.
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• In this way, by using the mentioned method to make the said particular composite systems, we could considerably increase the modulus of resilience and bearing capacity in bending "together with" significant decrease of the weight and also the possibility of beam fracture of primary compressive type. Through making these particular integrated functioning systems, for the first time, the said (paradoxical) properties have been concomitantly fulfilled in "one functioning unit" altogether.
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• Respect to the special pattern of the strain changes during bending in the particular Resilient Composite System termed ECRLC, this system as an integrated functioning unit with the reticular arrangement and texture has more strain capability (particularly within the elastic limit), energy absorption and load bearing capacities in bending compared to the usual reinforced concrete beams.
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• Thereby, through employing this applied structure, solving some of the main problems in lightweight concretes application, especially the deadlock of brittle and insecure being of fracture pattern in many of the usual reinforced lightweight concrete structures, is provided; reaching to the high bearing capacities in bending elements (even with low dimensions & weights) is to hand, and getting access to a simple and practical opportunity for "qualitative development of possibilities of using lightweight concretes" (especially with oven-dry densities of < 1350-1400kg/m3 and compressive strengths of <14-17mpa, and even with oven-dry densities of < 800kg/m3) is conceivable.
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• Naturally, by more studies in the field, these structures and their applications in various fields could be developed more.
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***
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/ ► FULL TEXT (Open Access):
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- http://arxiv.org/abs/1510.03933 
( https://arxiv.org/ftp/arxiv/papers/1510/1510.03933.pdf ) ;
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. Kamyar Esmaeili: "Elastic Composite Reinforced Lightweight Concrete as a Type of Resilient Composite Systems";
The Internet Journal of Innovative Technology and Creative Engineering (IJITCE); 2012; 2(8): 1-22.
- http://ia800305.us.archive.org/34/items/IJITCE/vol2no801.pdf [Also archived at: http://www.webcitation.org/6B2pFPpBh ] ;
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- https://www.scribd.com/doc/11530978/Elastic-Composite-Reinforced-Lightweight-Concrete-ECRLC-as-a-type-of-Resilient-Composite-Systems-RCS-http-arxiv-org-abs-1510-03933 ; 
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- https://sites.google.com/site/NEWSTRUCTURE1 ;
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- https://sites.google.com/site/newstructure1/publications-page/ELASTIC%20COMPOSITE%2C%20REINFORCED%20LIGHTWEIGHT%20CONCRETE%20AS%20A%20TYPE%20OF%20RESILIENT%20COMPOSITE%20SYSTEMS.pdf ;
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- http://www.pdf-archive.com/2015/09/22/elasticcomposite-reinforcedlightweightconcreteasatypeofrcs/elasticcomposite-reinforcedlightweightconcreteasatypeofrcs.pdf ;
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- The link to the document in PDF format on this site:
file:///C:/Users/pc5/Downloads/ELASTIC_COMPOSITE_REINFORCED_LIGHTWEIGHT.pdf ;
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- ...

The paper presents a research on real-time shape exploration employing analogue and digital form-finding and concludes with a proposal for a teaching methodology that led to an intensive student workshop which took place at Graz University of Technology during 2014. The aim was to experiment with analogue and digital tools in parallel, counter-informing the design process. The experiments involved physical form-finding following the tradition of Frei Otto at the Institute of Lightweight Structures in Stuttgart as well as computational form-finding employing mainly dynamic relaxation techniques of spring-particle systems. The combination of techniques and methodologies eventually led to a feedback loop across different media that explored both qualitative and quantitative characteristics of the projects at hand. By establishing feedback between digital media and physical prototypes, the creative process is immediately informed by the material characteristics and properties which in turn give rise to a real-time exploration of form.Simulations of physical forces for architectural form generation are increasingly gaining ground in architectural education as there is a broad selection of computational tools readily available that allow quick experiments to be conducted. Form-finding is a well-established method in architecture and engineering aiming to define the optimal geometry with respect to the structural behavior for certain boundary conditions. There is a long history of experimentation in this field, supported by scientific research and built examples. Frei Otto was the pioneer to research, study and categorize these structures, together with his team at the Institute for Lightweight Structures in Stuttgart. Their physical experiments and models have been documented in the famous volumes of IL books; although most of the IL series were published in the early 70s, which is much before the wide use of computational design in architecture, they remain an essential reading for CAAD Education-Tools-Volume 2-eCAADe 33 | 135

An aircraft structural assembly includes an area element which has a core and an outer layer. A first surface of the area element is convexly curved, at least in certain sections, relative to an imaginary central area of the area element extending through the core of the area element.

Nowadays, different research teams are engaged on experimental and theoretical studies having as main aim the evaluation of seismic performance of sheathed cold-formed steel frame structures. Although a relatively large number of experimental and theoretical studies are available, the development of useful tools for the seismic design should be improved. As an attempt to overcome this lack, this paper aims to present a structural design procedure that allows, through the definition of three design nomographs, the screw spacing and all the shear walls components to be obtained on the basis of linear dynamic or nonlinear static seismic analysis. In addition, a procedure for the prediction of the whole pushover response curve of sheathed cold-formed steel shear walls, which can be advantageously used for developing the design nomographs, is presented.

Load bearing organic structures are often composed of fibrous materials. Trees that create their own structure in an architectural scale are good examples. It is no wonder trees have been a living inspiration for architecture from the very beginning. However, there is an alternative way of using fibrous materials. Cellulose, which builds trees and herbaceous plants, shows many similarities to chitin from a chemical point of view. In nature, chitin is one of the structural materials of fungi and insect exoskeletons. In addition, it is also a building material for shell structures (Vincent, 2012). Research on ultra-lightweight structures has already proven that the microstructure geometry of insect exoskeletons can be used to construct vaults built from fibrous materials (Knippers et al., 2015). Long-fibre reinforced composites have a high resistance to tensile stress but they usually perform poorly to compression and bending. Because of this, it is more practical to apply geometries that are mainly subject to tension. Our goal was to create a biocomposite structure that is tensile to the greatest possible extent. The "tensegrity" structures bear continuous tension, and their bar elements are separately positioned in order to resist pressure (Gan, 2020). Kenneth Snelson (2012) pointed out that enveloping a tensegrity structure produces an origami form. Accordingly, one can easily turn a tensegrity framework into a folded board construction. Following this idea, several related experiments were performed. In 2012, a life-size model of a pavilion was shown, which had fixed aluminium bars covered with a textile membrane. The textile membrane was formed into a mechanically ideal shape so that we could use it as a basic form to explore new models of biocomposite construction. Hence, we followed the path of structurally ideal shapes defined by nature itself.

Characterized by continuity, inventiveness, and a fervent exploration of the relationship between architecture and the environment at large, the work of Lisbeth Sachs was included in the 1979 issue of the Aktuelles Bauen magazine on women and architecture. This contribution proposes an in-depth review of Sachs’s underexplored work, suggesting
a better understanding of her role as a practicing woman architect at a time when this task was not a matter of course. It places an emphasis on the dialogue Sachs established with her contemporaries, on the dense network of experiences that shaped her design approach, and on the ways it intersected with the late twentieth-century discourse on the relationship between architecture, ecology, and nature. It is not coincidental that the work of Frei Otto would have a long-lasting influence on Sachs’s design experimentation, informing her theoretical and applied design projects. Her design exploration, too, was influenced by the technological advances, the societal changes and the shifts in the cultural agency of architecture, proposing each time a solution that addressed, rather than excluded, its surrounding context, cultural, physical, or environmental.

The research project presented in this paper aims to extend the repertoire of architectural design and construction. To achieve this purpose, research-through-design methods are used to match a commonly desired target geometry with a realistic and efficient materialisation strategy. The proposed approach has been tested through construction of practical prototypes that eventuated in a full-scale structure that performed well in a variety of outdoor conditions. The outcome of this work is a workflow for semi-automated skinning of complex graphs such as trusses or space frames. The project tests this workflow through an application to a topologically complex L-system. The L-system graph is parametrically skinned with a continuous, adjustable envelope. The outcomes of this skinning are materialised in fabric to produce a twelve-metrelong, wind-supported, airborne inflatable structure. This workflow is a novel extension of existing approaches to skinning and fabrication of structures based on complex graphs because it allows a hitherto unavailable, fabrication-ready geometric definition of joints between cylindrical and conical tubes of varying diameters. It is significant as a reusable approach to the geometric construction of such joints in a variety of materials and across multiple scales. Furthermore, it is interesting as an innovative prototype of possible wind-supported architectural structures.

The impact responses of brazed and adhesively bonded layered 1050 H14 trapezoidal corrugated aluminum core and aluminum sheet interlayer sandwich panels with 3003 and 1050 H14 aluminum alloy face sheets were investigated in a drop weight tower using spherical, flat and conical end striker tips. The full geometrical models of the tests were implemented using the LS-DYNA. The panels tested with spherical and flat striker tips were not penetrated and experienced slightly higher deformation forces and energy absorptions in 0°/90°corrugated layer orientation than in 0°/0°orientation. However, the panels impacted using a conical striker tip were penetrated/perforated and showed comparably smaller deformation forces and energy absorptions, especially in 0°/90°layer orientation. The simulation and experimental force values were shown to reasonably agree with each other at the large extent of deformation and revealed the progressive fin folding of corrugated core layers and bending of interlayer sheets as the main deformation mechanisms. The experimentally and numerically determined impact velocity sensitivity of the tested panels was attributed to the micro inertial effects which increased the critical buckling loads of fin layers at increasingly high loading rates.

This paper proposes a novel design for a self-standing tensegrity dome, meaning that it doesn't require the use of rigid compression rings or fixed nodes. The structure is designed as the assembly of three tensegrity units composed of six bars each one, with an initial hemispherical shape, and its equilibrium matrix A is calculated. By using the force density method, the singular value decomposition SVD of the equilibrium and force density matrices are executed iteratively until the nodal coordinates and the force densities of the members correspond to a stable configuration. A numerical example and a real model are illustrated to demonstrate the efficiency of this method.

► SUMMARY:

♦ The Resilient Composite Systems (R.C.S.) could be counted as "The Methodically Reinforced Nonlinear Porous Materials", also having the high specific modulus of resilience in flexure. They are the compound materials, with some particular structural properties, in which, contrary to the basic geometrical assumption of the flexure theory in Solid Mechanics, the strain changes in the beam height during bending is typically "Nonlinear". The Resilient Composite Systems are made by expediently creating the disseminated suitable hollow pores and/or by distributing the appropriate lightweight aggregates throughout the methodically reinforced, fibered conjoined matrix so that; "the strain changes in the beam height during bending" is typically "nonlinear". Thereby, by applying the mentioned method to make the said composite systems, "considerably increasing the modulus of resilience and the bearing capacity in bending" together with "the significant decrease of the weight" and "the removal of the beam fracture possibility of primary compressive type" have been feasible. Through making these particular consistently functioning systems, the above-stated paradoxical virtues have been concomitantly fulfilled in "one functioning unit" altogether.

♦ The RCS (with the mentioned general structural properties and specific functional criteria) whose cement materials include the "C-S-H (Calcium Silicate hydrate) crystals" have been termed "Elastic Composite, Reinforced Lightweight Concrete (E.C.R.L.C.)".

♦ The RCS and ECRLC as a kind of RCS could be used in many cases. For instance, "Constructing Lightweightly and Consistently", also with practically utilizing the RCS and ECRLC in particular, can be counted as the pivotal and practical tactic to effectively increase the resistance & safety of the constructions against "earthquake" and lateral forces, in the large extent. For example, using some lightweight and insulating, "non-brittle", reinforced sandwich panels or 3D-panels, "with the high modulus of resilience and appropriate behavior against the bending loads and impacts", for construction could be taken into consideration according to the case... [It is worth remarking that; contrary to the ECRLC, the usual reinforced lightweight concretes, especially in the very low densities, are dramatically brittle; they do not have the appropriate behavior and resistance against the high bending loads and impacts.]
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● "Resilient Composite Systems (RCS)":

♦ "Resilient Composite Systems" (RCS) are the compound materials, having some particular structural properties, in which, contrary to the basic geometrical assumption of the flexure theory in Solid Mechanics, the strain changes in the beam height during bending is typically "Nonlinear". The RCS could be counted as "The Methodically Reinforced Nonlinear Porous Materials", also having the high specific modulus of resilience in flexure. (Elastic Composite, Reinforced Lightweight Concrete; ECRLC is a type of RCS with the mentioned specifics.)

♦ Generally, the Resilient Composite Systems comprise these components as the main, necessary elements:
• 1) Mesh (Lattice);
• 2) Fibers or strands;
• 3) Conjoined matrix, having the disseminated suitable pores and/or the disseminated appropriate lightweight aggregates beads or particles. [Here, the general term of "lightweight aggregate" has a broad meaning, also including the polymeric and non-polymeric beads or particles.]

♦ The Resilient Composite Systems are made by creating the disseminated suitable hollow pores and/or by distributing the appropriate lightweight aggregates throughout the reinforced, fibered conjoined matrix so that; "the strain changes in the beam height during bending" is typically "nonlinear". Thereby, by applying the mentioned method to make the said particular composite systems, "considerably increasing the modulus of resilience and the bearing capacity in bending" together with "the significant decrease of the weight" and "the removal of the beam fracture possibility of primary compressive type" have been feasible. Through making these particular consistently (unitedly, integratedly) functioning systems, the stated paradoxical virtues have been concomitantly fulfilled in one functioning unit altogether.

♦ Generally, in these consistently functioning units, the amount and the use manner of the mentioned components in the organized system are so that; the reciprocal interactions among the components finally lead to the "typically nonlinear strain changes in the beam height during bending" (as the "basic functional character" of these systems with the specific testable criteria and indices) and the functional specifications fulfillment of the system.

♦ In the RCS in general, the main strategy to raise the modulus of resilience in bending is "increasing the strain capability of the system in bending" within the elastic limit.

♦ Here, the main tactic to realize the stated strategy is: "creating the suitable hollow pores and/or using the appropriate lightweight aggregates, all disseminated throughout the methodically reinforced conjoined matrix", to provide the possibility for occurring of the expedient internal deformities in the matrix during the bending course, which could lead to the more appropriate distribution of the stresses and the strains throughout the system and the more strain capability of the beam in flexure. On the other hand, only creating the hollow pores and/or using the lightweight aggregates in the matrix, by itself, not only cannot lead to the mentioned goals but also brings about weakening of the matrix and its fragility. Hence, concomitantly, the matrix should be well supported and strengthened. Here, this essentially ameliorating and strengthening the matrix are performed by giving attention to "the internal consistency of the matrix" and also via "employing the expedient reinforcements in two complementary levels": 1) Using the fibers to the better distribution of the tensile stresses and strains in the matrix, and to increase the matrix endurance and the modulus of resilience in tension and bending; 2) Using the mesh or lattice to better distribution of the tensile stresses and strains in the system, and to increase the system endurance and the modulus of resilience in tension and bending.

♦ In these systems, the presence of the mentioned hollow pores and/or lightweight aggregates disseminated throughout the conjoined matrix (which has been ameliorated through making "an integrated, reticular structure") provides the possibility for occurring of the expedient internal deformities in the matrix during the bending course. By the way, this can lead to the less accumulation of the internal stresses in the certain points of the matrix during bending, the better absorption and control of the stresses, and providing the more strain capability of the beam, especially within the elastic limit.

♦ The occurrence of the remarked internal deformities in the said methodically reinforced matrix during the bending course also means; the occurrence of the deformities in the said hollow pores and/or lightweight aggregates well disseminated throughout the conjoined matrix, in two different forms. Indeed, we have the internal deformities in the fibered lightweight matrix of the system throughout the bending course, in two main different forms, leading to: A) The comparative increase of the thickness (height) of the in-compressing layers (particularly in the upper parts of the beam) and the conversion of some internal compressive stresses to the internal tensile stresses (on the axis perpendicular to the mentioned internal compressive tensions) in the in-compressing layers; B) The comparative decrease of the thickness (height) of the in-tension layers (particularly in the lower parts of the beam) and the conversion of some internal tensile stresses to the internal compressive stresses (on the axis perpendicular to the mentioned internal tensile tensions) in the in-tension layers.

♦ In the under-bending sections of the "Resilient Composite Systems", the deformities occurring in the "conjoined layers perpendicular to the applied load direction" during the bending course are so that; "the initially plane sections perpendicular to the beam axis" typically shift from "the plane status" to "the curve status" during the bending course. Thereby, the basic geometrical assumption of the flexure theory in Solid Mechanics ("linearly" being of the strain changes in the beam height during bending) and the respective trigonometric equations & equalities are mainly overshadowed in these systems.

♦ This way, through occurring of the remarked internal deformities in the strengthened matrix during the flexure course, the stresses are more distributed and absorbed, and the rise rate of the internal stresses in the matrix ... reduces.  ...
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► [sites.google.com/site/newstructure1]

Design optimization for Additive Manufacturing is demonstrated by the example of an industrial robot link. The part is first redesigned so that its shape details are compatible with the requirements of the Selective Laser Sintering technique. Subsequently, the SIMP method of topology optimization is utilized on commercially available software in order to obtain the optimum design of the part with restrictions applicable to Additive Manufacturing, namely member thickness, symmetry and avoidance of cavities and undercuts. Mass and strain energy are the design responses. The volume was constrained by a fraction of the initial mass. The desired minimization of maximum strain energy is expressed as an objective function. A 7% reduction in the mass of the part was achieved while its strength and stiffness remained unchanged. The process is supported by topology optimization software but it also involves some trial-and-error depending on the designer's experience.

This paper describes a new approach to designing and fabricating costuming and dancing sculptures and the potential application of this system at the architectural scale. I present a novel design system based on the movement, form, and spatial relation of characters and dancing sculptures in the Trinidad Carnival. I also present a system that produces lightweight mobile structures from 3D printed connections, lightweight rods, and textile. Through a detailed case study, a new dancing sculpture is designed, and a full-scale lightweight mobile structure at the architectural scale is fabricated. Fabrication of the lightweight structure is achieved using Digital Crafting and Crafting Fabrication approaches to wire-bending, which includes the early development of a digital fabrication program for rod elements. This work has potential implications for costuming and dancing sculptures; architecture; computational design; and craft practices.

The potentiality of cold-formed steel structures (CFS) in terms of lightness, rapid on-site erection and high structural performance is spreading the use of the technology in the most industrialized countries. In particular, the overall recognized capability to assure a good structural response in high seismic areas is allowing the adoption in some of the most conservative communities. On the other hand, despite the many ongoing research in different countries, the current seismic design codes are often inadequate if compared to the evolutionary process. In this context, the new British Force School (BFS) represents one of the first cold-formed steel structures realized in Italy and, therefore, it required a long and complex verification process. Indeed, the seismic performance at the global and local scale had to be verified during the construction phase. This paper focuses on the evaluation of lateral response of the sheathed cold-formed steel (SCFS) shear walls, which represent the seismic resisting system of this structural typology through the presentation and discussion of the experimental campaign carried out to support the design.

This paper describes a new approach to designing and fabricating costuming and dancing sculptures and the potential application of this system at the architectural scale. I present a novel design system based on the movement, form, and spatial relation of characters and dancing sculptures in the Trinidad Carnival. I also present a system that produces lightweight mobile structures from 3D printed connections, lightweight rods, and textile. Through a detailed case study, a new dancing sculpture is designed, and a full-scale lightweight mobile structure at the architectural scale is fabricated. Fabrication of the lightweight structure is achieved using Digital Crafting and Crafting Fabrication approaches to wire-bending, which includes the early development of a digital fabrication program for rod elements. This work has potential implications for costuming and dancing sculptures; architecture; computational design; and craft practices.

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