On laminate selection and design
22 Apr 2002-
TL;DR: In this article, a database is used to store appropriate properties of all permutations of lay-up angles for a laminate and then the designer can select viable laminates by first plotting a succession of 2D charts containing relevant properties.
Abstract: Composite materials, at one level, are exciting to work with because they give scope for designing the “material” in addition to a “structure” through judicious placement of the orientation of plies. It is their ability to tailor material properties layer by layer that give designers huge potential in design. One possible explanation for the prevalent use of quasiisotropic (“black aluminium”) carbon composites in structures is the lack of available design tools. Here a design tool is presented that aids selection of fibre orientations. Optimisation of laminate fibre angles is difficult for multiple load cases and objectives-there are many local minima to assess. An alternative approach to complex / numerical optimisation methods, is presented here The basic idea is to build a database that stores appropriate properties of all permutations of lay-up angles for a laminate. The designer can select viable laminates by first plotting a succession of 2-D charts containing relevant properties. Then, using simple on-screen techniques, the number of potential laminates is visually reduced by selecting those with desirable properties. Two case studies are presented. The first concerns the optimisation of a spar web, typically found in an aircraft wing structure whilst the second considers the optimisation of a cylindrical shell, subject to axial compression, that undergoes simultaneous Euler-type buckling and local buckling. Nomenclature
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TL;DR: This paper presents a methodology to help designers select a shortlist or optimum design of composite structure from a large number of alternatives, taking into account conflicting design objectives or constraints (e.g. weight and cost).
42 citations
Cites background or methods from "On laminate selection and design"
...In essence the method builds on Weaver’s methodology for laminate selection [17], but introduces structural analysis into the methodology, recognising the way in which structure and laminate lay-up are closely coupled in composites design....
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...presented here is an alternative approach to complex numerical optimisation methods, and is based on the use of 2-D charts to evaluate laminate performance [2,3,17,10,13]....
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...When all these factors are taken into account, along with the need to consider different load cases and design objectives, tailoring the geometry, material properties and lay-up of the composite laminate to find an optimum design is very challenging [6,17,10,11]....
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01 Jan 2017
TL;DR: There is an urgent need for a systematic approach of a (intelligent) topology-optimized methodology focused on a detailed, but also integrated constructive and technological procedure to specify and optimize composite structures within nowadays requested multi-material systems.
Abstract: e for the product development of (high-tech) lightweight systems across several industries. Accordingly, apart from the today’s extensive gain in constructive and technological engineering skills, particularly new high-strength materials lead to satisfy the present rigorous requirements (e.g. mandatory national CO2 regulations in automotive industry) for lightweight engineering in a much deeper dimension. Nevertheless, advanced composites such as fiber-reinforced plastics (FRP) are often used as “black metal” by simply keeping the geometry of a metal component and replacing the material, even though the predicted performance will rarely match expectations. As a consequence, and to address hitherto untapped potentials in terms of lightweight design, there is an urgent need for a systematic approach of a (intelligent) topology-optimized methodology focused on a detailed, but also integrated constructive and technological procedure to specify and optimize composite structures within nowadays requested multi-material systems. Therefore, a corresponding approach is presented in this contribution.
1 citations
Cites methods from "On laminate selection and design"
...…accepted approach of Ashby and Johnson (2002) and provide a step-by-step guide in terms of a flowchart to the procedure, which is, in essence, built up on Weaver's methodology (Weaver, 2002) for laminate selection, but additionally introduces a structural analysis into the methodology....
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...(2008) orient themselves fundamentally to the internationally accepted approach of Ashby and Johnson (2002) and provide a step-by-step guide in terms of a flowchart to the procedure, which is, in essence, built up on Weaver's methodology (Weaver, 2002) for laminate selection, but additionally introduces a structural analysis into the methodology....
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07 Apr 2003
1 citations
TL;DR: In this paper, the direction factor of bending stiffness was defined in terms of the proportional coefficient of the bending stiffness corresponding to the identical ply orientations, as well as a new iterative mode, cycle after symmetry, of the laminate.
Abstract: The direction factor of the bending stiffness was defined in terms of the proportional coefficient of the bending stiffness corresponding to the identical ply orientations, as well as a new iterative mode, cycle after symmetry, of the laminate. On the basis of the quasi-isotropic laminate, the method of the direction factor of bending stiffness considerably reduces the computational capacity with respect to the quasi-homogeneity. By means of the method of the direction factor and comparison of the direction factors corresponding to three kinds of laminates, the iterative mode of cycle after symmetry has superior performance than the common iterative modes, which is applicable to the design and optimization of the laminate, especially for the homogeneous laminate.
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16 Sep 1992
TL;DR: The design process engineering materials and their properties materials selection charts materials selection without shape selection of material and shape materials processing and design sources of material property data materials, aesthetics and industrial design forces for change case studies as mentioned in this paper.
Abstract: The design process engineering materials and their properties materials selection charts materials selection without shape selection of material and shape materials processing and design sources of material property data materials, aesthetics and industrial design forces for change case studies.
2,975 citations
Book•
01 Jan 1992
TL;DR: The design process engineering materials and their properties materials selection charts materials selection without shape selection of material and shape materials processing and design sources of material property data materials, aesthetics and industrial design forces for change case studies.
Abstract: The design process engineering materials and their properties materials selection charts materials selection without shape selection of material and shape materials processing and design sources of material property data materials, aesthetics and industrial design forces for change case studies.
2,343 citations
Book•
01 Jan 1938
TL;DR: This chapter discusses the Behavior of Bodies Under Stress, which involves tension, Compression, Shear, and Combined Stress, and the role of Fasteners and Joints in this Behavior.
Abstract: Chapter 1. Introduction Chapter 2. Stress and Strain: Important Relationships Chapter 3. The Behavior of Bodies Under Stress Chapter 4. Principles and Analytical Methods Chapter 5. Numerical Methods Chapter 6. Experimental Methods Chapter 7. Tension, Compression, Shear, and Combined Stress Chapter 8. Beams Flexure of Straight Bars Chapter 9. Curved Beams Chapter 10. Torsion Chapter 11. Flat Plates Chapter 12. Columns and Other Compression Members Chapter 13. Shells of Revolution Pressure Vessels Pipes Chapter 14. Bodies under Direct Bearing and Shear Stress Chapter 15. Elastic Stability Chapter 16. Dynamic and Temperature Stresses Chapter 17. Stress Concentration Chapter 18. Fatigue and Fracture Chapter 19. Stresses in Fasteners and Joints Chapter 20. Composite Materials Chapter 21. Solid Biomechanics Appendix A. Properties of a Plane Area Appendix B. Mathematical Formulas and Matrices Appendix C. Glossary Index
2,050 citations
TL;DR: In this article, it is shown that St. Venant's solution of the flexure problem is not supported by ordinary engineering practice, and recent experience in the use of high tensile steels and problems of aircraft structure have emphasised the desirability of a further examination of the Flexure problem.
Abstract: It is a generally appreciated deduction from St. Venant’s solution of the flexure problem that a beam in which the material is disposed at a distance from the neutral axis is superior to the solid section in economy of material. St. Yenant’s solution, however, suggests that this advantage increases without limit as the thickness of the material is reduced and the distance from the neutral axis is increased. It has, of course, been generally realised that this conclusion is not supported by ordinary engineering practice, and recent experience in the use of high tensile steels and problems of aircraft structure have emphasised the desirability of a further examination of the flexure problem. St. Venant’s solutions are obtained when the equations of equilibrium of an isotropic elastic solid are made linear by the neglect of terms of higher orders than the first: and by Kirchhoff’s theorem of determinancy these solutions may then be considered unique and stable. To attack problems of stability it is necessary, as is shown by R. V. Southwell in his ‘General Theory of Elastic Stability,’ to include some of the second order effects. It is, in fact, only when these become considerable that Kirchhoff’s theorem fails and instability becomes possible. By this general treatment various classes of instability are obtained or indicated, but the only ones susceptible to analysis or of practical interest (on account of the “elastic limit” which is a feature of all practical materials) are those in which at the moment of instability the strains are still small. Bryant has shown that this will only occur, as in the case of thin rods and shells, when one dimension of the body is small compared with others.
561 citations
TL;DR: The basic mechanical and thermal properties of engineering materials are surveyed and inter-related in this article, revealing the range of each property, and the sub-range associated with each material class.
303 citations