A Wrinkled Membrane Model for Cloth Draping with Multigrid Acceleration

1999 ◽  
Vol 121 (4) ◽  
pp. 695-700
Author(s):  
M. X. Chen ◽  
Q. P. Sun ◽  
Z. Wu ◽  
M. M. F. Yuen
Keyword(s):  
Finite Element ◽  
Energy Density ◽  
Material Model ◽  
Element Formulation ◽  
Membrane Theory ◽  
Material Parameters ◽  
Quadrilateral Elements ◽  
Proposed Model ◽  
Wrinkled Membrane ◽  
Cloth Draping

Fabric is modeled as a particular type of membrane formed from two orthogonal families of yarns. In contrast to usual membrane theory, the fabric is regarded to possess a certain compressive rigidity which is much weaker than its tensile rigidity. An energy density function is defined corresponding to the material model. The finite element formulation is based on the total Lagrangian approach. Four node quadrilateral elements are adopted. An accelerated multigrid technique using the conjugate gradient method as basic iterative method is employed to minimize energy to reach the final equilibrium position. Two examples of fabric draping are analyzed using the proposed model. The influence of the material parameters on the draping behavior is discussed.

Lifetime Prediction of Tires with Regard to Oxidative Aging5

2008 ◽  
Vol 36 (1) ◽  
pp. 63-79 ◽  
Author(s):  
L. Nasdala ◽  
Y. Wei ◽  
H. Rothert ◽  
M. Kaliske
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Temperature Distribution ◽  
Superposition Principle ◽  
Accelerated Aging ◽  
Material Model ◽  
Aging Behavior ◽  
Element Analysis ◽  
Material Parameters ◽  
Reaction Processes

Abstract It is a challenging task in the design of automobile tires to predict lifetime and performance on the basis of numerical simulations. Several factors have to be taken into account to correctly estimate the aging behavior. This paper focuses on oxygen reaction processes which, apart from mechanical and thermal aspects, effect the tire durability. The material parameters needed to describe the temperature-dependent oxygen diffusion and reaction processes are derived by means of the time–temperature–superposition principle from modulus profiling tests. These experiments are designed to examine the diffusion-limited oxidation (DLO) effect which occurs when accelerated aging tests are performed. For the cord-reinforced rubber composites, homogenization techniques are adopted to obtain effective material parameters (diffusivities and reaction constants). The selection and arrangement of rubber components influence the temperature distribution and the oxygen penetration depth which impact tire durability. The goal of this paper is to establish a finite element analysis based criterion to predict lifetime with respect to oxidative aging. The finite element analysis is carried out in three stages. First the heat generation rate distribution is calculated using a viscoelastic material model. Then the temperature distribution can be determined. In the third step we evaluate the oxygen distribution or rather the oxygen consumption rate, which is a measure for the tire lifetime. Thus, the aging behavior of different kinds of tires can be compared. Numerical examples show how diffusivities, reaction coefficients, and temperature influence the durability of different tire parts. It is found that due to the DLO effect, some interior parts may age slower even if the temperature is increased.

scholarly journals Buckling and Free Vibration Analysis of Laminated Sandwich Beams under Hygrothermal Conditions

2021 ◽  
Vol 2070 (1) ◽  
pp. 012170
Author(s):  
A Garg ◽  
S Gupta ◽  
HD Chalak
Keyword(s):  
Finite Element ◽  
Free Vibration ◽  
Fourth Order ◽  
Vibration Analysis ◽  
Loading Condition ◽  
Free Vibration Analysis ◽  
Element Formulation ◽  
Sandwich Beams ◽  
Proposed Model ◽  
Zigzag Theory

Abstract In present work, an attempt has been made for carrying out free vibration and buckling analysis of laminated sandwich beams under hygrothermal conditions. The analysis is carried out using fourth order zigzag theory based on finite element formulation. The efficiency of proposed model is validated by comparing the present results with those available in literature. Geometric properties and loading condition widely affect the behavior of the laminated sandwich beams.

Free and constrained inflation of elastic membranes in relation to thermoforming — non-axisymmetric problems

1989 ◽  
Vol 24 (2) ◽  
pp. 55-74 ◽  
Author(s):  
J M Charrier ◽  
S Shrivastava ◽  
R Wu
Keyword(s):  
Finite Element ◽  
Computer Program ◽  
Material Model ◽  
Experimental Investigations ◽  
Element Formulation ◽  
Aspect Ratios ◽  
Elastic Membranes ◽  
Axisymmetric Problems ◽  
Theoretical Results ◽  
Single Constant

This paper deals with the inflation of elastic membranes of general shapes in the context of thermoforming of heated polymeric sheets against relatively cold moulding surfaces. A previous paper (1) has dealt with axisymmetric problems. As before, both theoretical and experimental investigations are reported. The theoretical part consists of a self-contained finite element formulation for large deformation, free and constrained inflation of isotropic elastic membranes. The computer program developed on the basis of presented formulation is applied to free and constrained inflation of plane elliptical membranes of aspect ratios 2 and 4. The material model adopted is that of a single constant neo-Hookean elastic material. The constrained analyses are carried out for inflation against: (a) cylindrical walls (90 degree elliptical cones), (b) 60 degree elliptical cones, and (c) horizontal plates. Separate analyses are performed by assuming the contact to be either slipless or frictionless. The theoretical results are compared with the experimental ones for free inflation and constrained inflation cases (a) and (c).

Study on Key Factors of Numerical Simulation on Automotive Panel Forming

2012 ◽  
Vol 503-504 ◽  
pp. 115-118
Author(s):  
Qiang Wang
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Adaptive Mesh ◽  
Material Model ◽  
Element Formulation ◽  
Key Factors ◽  
Shell Elements ◽  
Automobile Panel ◽  
Hourglass Control ◽  
Element Type

In this paper, for improving simulative accuracy of auto panel forming, some key factors of numerical simulation with finite element method on automobile panel stamping forming are researched. These key factors include finite element algorithm, adaptive mesh, element type and element formulation, hourglass control, material model, and so on. Through simulation example and analysis show that the dynamic explicit algorithm is suitable for metal stamping forming and the static implicit algorithm for springback stage, the adaptive mesh must be adopted in sheet blank forming, element should be selected shell elements, material model should be selected Barlat’s 3-parameter plasticity model.

A Pressure Projection Method for Nearly Incompressible Rubber Hyperelasticity, Part II: Applications

1996 ◽  
Vol 63 (4) ◽  
pp. 869-876 ◽  
Author(s):  
Jiun-Shyan Chen ◽  
Cheng-Tang Wu ◽  
Chunhui Pan
Keyword(s):  
Finite Element ◽  
Energy Density ◽  
Projection Method ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Finite Elasticity ◽  
Element Formulation ◽  
Density Functions ◽  
Hyperelastic Materials ◽  
Pressure Projection

In the first part of this paper a pressure projection method was presented for the nonlinear analysis of structures made of nearly incompressible hyperelastic materials. The main focus of the second part of the paper is to demonstrate the performance of the present method and to address some of the issues related to the analysis of engineering elastomers including the proper selection of strain energy density functions. The numerical procedures and the implementation to nonlinear finite element programs are presented. Mooney-Rivlin, Cubic, and Modified Cubic strain energy density functions are used in the numerical examples. Several classical finite elasticity problems as well as some practical engineering elastomer problems are analyzed. The need to account for the slight compressibility of rubber (finite bulk modulus) in the finite element formulation is demonstrated in the study of apparent Young’s modulus of bonded thin rubber units. The combined shear-bending deformation that commonly exists in rubber mounting systems is also analyzed and discussed.

Mixed Finite Element for Geometrically Nonlinear Orthotropic Shallow Shells of Revolution

2014 ◽  
Vol 919-921 ◽  
pp. 1299-1302 ◽  
Author(s):  
Leonid U. Stupishin ◽  
Konstantin E. Nikitin
Keyword(s):  
Finite Element ◽  
Numerical Method ◽  
Orthotropic Material ◽  
Mixed Finite Element ◽  
Material Model ◽  
Element Formulation ◽  
Geometrically Nonlinear ◽  
Shells Of Revolution ◽  
Test Task ◽  
Shallow Shells

A numerical method for mixed finite-element formulation shallow shells of revolution is developed. Orthotropic material model is considered. Final equations are derived by the Galerkin’s method. Results of solution of test task are represented. Results precision and convergence are analyzed.

Inverse Finite Element Analysis of the Indentation Response of Human Cervical Tissue

2013 ◽  
Author(s):  
Kristin Myers ◽  
Wang Yao ◽  
Kyoko Yoshida ◽  
Joy Vink ◽  
Noelia Zork ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Viscoelastic Material ◽  
Material Model ◽  
Spherical Indentation ◽  
Cervical Tissue ◽  
Tissue Slices ◽  
Element Analysis ◽  
Material Parameters ◽  
Inverse Finite Element Analysis

The mechanical function of the cervix is crucial during pregnancy when it is required to resist the compressive and tensile forces generated from the growing fetus. Pathologies of the cervical extracellular matrix (ECM), premature cervical remodeling, and alterations of cervical material properties have been implicated in placing women at high-risk for preterm birth (PTB). To understand the mechanical role of the cervix during pregnancy and to potentially identify etiologies for PTB, the overall goal of our group is to quantify ECM-material property relationships in normal and diseased human cervical tissue. In this study we present an inverse finite element analysis (IFEA) that optimizes material parameters of a viscoelastic material model to fit the stress-relaxation response of excised tissue slices to spherical indentation. Here we detail our IFEA methodology, report viscoelastic material parameters for cervical tissue slices from nonpregnant (NP) and pregnant (PG) hysterectomy patients, and report slice-by-slice data for whole cervical tissue specimens.

Stability of Layered Structures with Hybridized Configuration by Means of a Reddy-Type Higher-Order Finite Element Formulation

2021 ◽  
pp. 2150045
Author(s):  
Zhen Wu ◽  
Jie Zhou ◽  
Zhengliang Liu ◽  
Rui Ma ◽  
Xiaohui Ren
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Three Dimensional ◽  
Middle Surface ◽  
Layered Structures ◽  
Higher Order ◽  
Finite Element Formulation ◽  
Element Formulation ◽  
Buckling Loads ◽  
Proposed Model

To make use of the merit of designability, each lamina in layered structures may possess diverse materials and geometry to realize specific application. For the hybridized structures, geometry and material properties relative to the middle surface are generally unsymmetrical, which have a significant impact on stability. Some models might lose capability to deal with such issues, so that these issues are less reported. Within the developed models, Reddy’s model possesses merit of simplicity and efficiency, so a Reddy-type higher-order zig-zag model is constructed by utilizing the proposed zig-zag function (ZZF). Instead of the standard finite element formulation using the principle of minimum potential energy, the three-field Hu–Washizu (HW) mixed variational principle is employed to acquire the finite element formulation which can meet the harmonious conditions of transverse shear stress at the interface of adjacent layers. By investigating buckling behaviors of hybridized structures, performance of the proposed finite element formulation is appraised by comparing with the results obtained from the three-dimensional (3D) model as well as other models. Effect of boundary conditions (BCs), material properties, and span-to-thickness ratio on the buckling loads is also studied in detail. Numerical results show that buckling loads of hybridized structures are significantly impacted by the chosen parameters. The results acquired from proposed model are in very good agreement with those obtained from the layerwise (LW) model and the 3D finite element results.

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