Genesis of Ribbed Plate and Shells With Isotropic Density Dependent Material

1993 ◽  
Author(s):  
Hans P. Mlejnek
Keyword(s):  
Working Conditions ◽  
Isotropic Material ◽  
Material Model ◽  
Elastic Behaviour ◽  
Material Distribution ◽  
Isotropic Model ◽  
Material Density ◽  
Layer Structures ◽  
Optimal Material ◽  
Theoretical Considerations

Abstract An essential part in the genesis of structures or optimal material distribution is the relation between elastic behaviour and material density. This approach makes use of a isotropic material model, which leads to very simple working conditions. The isotropic model is directly formulated and utilized without employing homogenization based on an artificial microstructure. It is shown in theoretical considerations and demonstrated by examples, that this idea works also very easily with plate and shells, even for very general layer structures.

scholarly journals Optimization of Grillage-like Continuum by Triangle Plate Element

2012 ◽  
Vol 6 (1) ◽  
pp. 8-14
Author(s):  
Kemin Zhou ◽  
Xia Li
Keyword(s):  
Optimization Procedure ◽  
Material Model ◽  
Stress Constraints ◽  
Design Domain ◽  
Material Distribution ◽  
Plate Element ◽  
Design Variables ◽  
Plate Elements ◽  
Discrete Structures ◽  
Optimal Material

The volume of grillages with stress constraints is minimized. An optimal beams system or plate with reinforced ribs is obtained to present the optimal structure. A grillage-like continuum material model is adapted. Structure is analyzed by finite element method with triangle plate elements. The geometric matrix of triangle plate element in explicit formulation about area coordinates is presented. The stiffness matrix of grillage-like continuum material model is derived. The material distribution field in design domain is optimized by fully-stressed criterion. The densities and orientations of the beam or reinforced ribs at nodes in grillages are taken as design variables. The densities and orientations vary in design domain continuously. The optimal distribution fields of bend moments, flexure displacement and material are obtained simultaneously. Subsequently the discrete structures are founded based on the optimal material distribution fields. The performances of different elements are compared. The optimization procedure is accomplished by computer program automatically.

Numerical Experiments in Using Voronoi Cell Finite Elements for Topology Optimization

2009 ◽  
Author(s):  
James M. Gibert ◽  
Georges M. Fadel
Keyword(s):  
Topology Optimization ◽  
Isotropic Material ◽  
Numerical Experiments ◽  
Voronoi Cell ◽  
Material Model ◽  
Topological Optimization ◽  
Advantages And Disadvantages ◽  
Compliance Minimization ◽  
Design Variables ◽  
Standard Linear

This paper provides two separate methodologies for implementing the Voronoi Cell Finite Element Method (VCFEM) in topological optimization. Both exploit two characteristics of VCFEM. The first approach utilizes the property that a hole or inclusion can be placed in the element: the design variables for the topology optimization are sizes of the hole. In the second approach, we note that VCFEM may mesh the design domain as n sided polygons. We restrict our attention to hexagonal meshes of the domain while applying Solid Isotropic Material Penalization (SIMP) material model. Researchers have shown that hexagonal meshes are not subject to the checker boarding problem commonly associated with standard linear quad and triangle elements. We present several examples to illustrate the efficacy of the methods in compliance minimization as well as discuss the advantages and disadvantages of each method.

Establishment of an ANSYS-Based Constitutive Modeling for Age Forming of Aluminum Alloy

2012 ◽  
Vol 217-219 ◽  
pp. 1497-1500 ◽  
Author(s):  
Xiao Jun Zuo ◽  
Jun Chu Li ◽  
Da Hai Liu ◽  
Long Fei Zeng
Keyword(s):  
Aluminum Alloy ◽  
Constitutive Equation ◽  
Material Model ◽  
Tensile Tests ◽  
Material Constants ◽  
Tensile Process ◽  
Simulation Based ◽  
Optimal Material ◽  
Two Stages ◽  
Good Agreement

Constructing accurate constitutive equation from the optimal material constants is the basis for finite element numerical simulation. To accurately describe the creep ageing behavior of 2A12 aluminum alloy, the present work is tentatively to construct an elastic-plastic constitutive model for simulation based on the ANSYS environment. A time hardening model including two stages of primary and steady-state is physically derived firstly, and then determined by electronic creep tensile tests. The material constants within the creep constitutive equations are obtained. Furthermore, to verify the feasibility of the material model, the ANSYS based numerical scheme is established to simulate the creep tensile process by using the proposed material model. Results show that the creep constitutive equation can better describe the deformation characteristics of materials, and the numerical simulations and experimental test points are in good agreement.

Generative design and analysis of a double-wishbone suspension assembly: a methodology for developing constraint oriented solutions for optimum material distribution

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Aayush Bhat ◽  
Vyom Gupta ◽  
Savitoj Singh Aulakh ◽  
Renold S. Elsen
Keyword(s):  
Design Methodology ◽  
Manufacturing Industry ◽  
Optimization Technique ◽  
Design Solution ◽  
Material Distribution ◽  
Generative Design ◽  
Trade Off ◽  
Content Type ◽  
Life Study ◽  
Optimal Material

Purpose The purpose of this paper is to implement the generative design as an optimization technique to achieve a reasonable trade-off between weight and reliability for the control arm plate of a double-wishbone suspension assembly of a Formula Student race car. Design/methodology/approach The generative design methodology is applied to develop a low-weight design alternative to a standard control arm plate design. A static stress simulation and a fatigue life study are developed to assess the response of the plate against the loading criteria and to ensure that the plate sustains the theoretically determined number of loading cycles. Findings The approach implemented provides a justifiable outcome for a weight-factor of safety trade-off. In addition to optimal material distribution, the generative design methodology provides several design outcomes, for different materials and fabrication techniques. This enables the selection of the best possible outcome for several structural requirements. Research limitations/implications This technique can be used for applications with pre-defined constraints, such as packaging and loading, usually observed in load-bearing components developed in the automotive and aerospace sectors of the manufacturing industry. Practical implications Using this technique can provide an alternative design solution to long periods spent in the design phase, because of its ability to generate several possible outcomes in just a fraction of time. Originality/value The proposed research provides a means of developing optimized designs and provides techniques in which the design developed and chosen can be structurally analyzed.

Application of a Smooth Approximation of the Schmid’s Law to a Single Crystal Gas Turbine Blade: Part 1—Theory and Governing Equations

2012 ◽  
Author(s):  
Alessandro D. Ramaglia
Keyword(s):  
Single Crystal ◽  
Constitutive Models ◽  
Material Model ◽  
Research Literature ◽  
Elastic Behaviour ◽  
Full Potential ◽  
Smooth Approximation ◽  
Suitable Material ◽  
Von Mises ◽  
Term Creep

In industrial practice, the choice of the most suitable material model does not solely rely on the ability of the model in describing the intended phenomena. Most of the choice is often based on a trade-off between a great variety of factors. Robustness, cost and time for the minimum testing campaign necessary to identify the model and pre-existing standard practices are only a few of them. This is particularly true in the case of nonlinear structural analyses because of their intrinsic difficulties and the higher level of skills needed to carefully exploit their full potential. So, despite the great progress in this field, in certain cases it is desirable to use plasticity models that are rate-independent and possess very simple hardening terms. This is for example the case in which long term creep can be an issue or when the designer may want to treat separately different phenomena contributing to inelastic deformation. If the material to be modelled is isotropic, commercial FE packages are able to deal with such problems in almost every case. On the contrary for anisotropic materials like Ni-based super-alloys cast as single crystals, the choice of the designer is more limited and despite the large amount of research literature on the subject, single crystal constitutive models remain quite difficult to handle, to implement into FE codes, to calibrate and to validate. Such difficulties, coupled with the unavoidable approximations introduced by any model, often force the practice of using oversimplifications of the material behaviour. In what follows this problem is addressed by showing how single crystal plasticity modelling can be reduced to the adoption of an anisotropic elastic behaviour with a sort of von Mises yield surface.

Topological Optimization Technique for Free Vibration Problems

1995 ◽  
Vol 62 (1) ◽  
pp. 200-207 ◽  
Author(s):  
Zheng-Dong Ma ◽  
Noboru Kikuchi ◽  
Hsien-Chie Cheng ◽  
Ichiro Hagiwara
Keyword(s):  
Free Vibration ◽  
Optimization Algorithm ◽  
Optimization Problem ◽  
Optimization Technique ◽  
Topological Optimization ◽  
Material Distribution ◽  
Eigenvalue Optimization ◽  
Shift Parameter ◽  
Vibration Problems ◽  
Optimal Material

A topological optimization technique using the conception of OMD (Optimal Material Distribution) is presented for free vibration problems of a structure. A new objective function corresponding to multieigenvalue optimization is suggested for improving the solution of the eigenvalue optimization problem. An improved optimization algorithm is then applied to solve these problems, which is derived by the authors using a new convex generalized-linearization approach via a shift parameter which corresponds to the Lagrange multiplier and the use of the dual method. Finally, three example applications are given to substantiate the feasibility of the approaches presented in this paper.

Distribution Parameter Optimization of an FGM Pressure Vessel

2011 ◽  
Vol 320 ◽  
pp. 404-409
Author(s):  
Ze Wu Wang ◽  
Shu Juan Gao ◽  
Qian Zhang ◽  
Pei Qi Liu ◽  
Xiao Long Jiang
Keyword(s):  
Analytical Solution ◽  
Pressure Vessel ◽  
Material Properties ◽  
Optimization Design ◽  
Optimal Solution ◽  
Functionally Graded ◽  
Material Distribution ◽  
Optimization Scheme ◽  
Graded Material ◽  
Optimal Material

Functionally graded material (FGM) is well-known as one of the most promising materials in the 21stcentury, which has become the hot issue on its mechanical behavior and composition design. The optimization design of the material distribution properties for an FGM hollow vessel subjected to internal pressure were investigated in this paper. By constructing an exponentially function determining the material properties, the general analytical solution of the stresses of the FGM pressure vessel was given based on the Euler-Cauchy formula. And then, an optimization model for obtaining the optimal material distribution of FGM vessel was proposed coupling the general finite element (FE) code. The discrepancy between the analytical solution and the numerical solution was about 2%, which verified the reliability of the proposed models, and the optimization results also proved the feasibility of proposed optimization scheme because of arriving at the optimal solution in a few iterations. Results obtained would be helpful in designing an FGM pressure vessel.

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