A Simple w′(λ) Function for The Valanis-Landel Form of Stored Energy Function

1998 ◽  
Vol 71 (2) ◽  
pp. 234-243 ◽  
Author(s):  
Robert F. Landel
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Long Range ◽  
Energy Function ◽  
Good Accuracy ◽  
Linear Range ◽  
Stored Energy ◽  
Element Analysis ◽  
Strong Curvature

Abstract In the Valanis-Landel formulation of the stored energy function W, stresses depend on the function w′(λ)(=dw/dλ). This function exhibits strong curvature, making it difficult to represent analytically with good accuracy. It is found for both SBR and NR that the function λw′(λ) is not only far less curved, it is essentially linear in λ for the range of about 0.4 < λ < 2.0. The long range of simple proportionality to strain invites examination of molecular theories of rubberlike elasticity. Above the linear range the response can be approximated by kλn. These simplifications should make it easier to convert w′(λ) to the W1 and W2 functions employed in finite element analysis.

Bistable Compliant Four-Bar Mechanisms With a Single Torsional Spring

2006 ◽  
Author(s):  
Adarsh Mavanthoor ◽  
Ashok Midha
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Mechanism Design ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Stored Energy ◽  
Element Analysis ◽  
Bistable Behavior ◽  
Torsional Spring ◽  
Bistable Mechanism

Significant reduction in cost and time of bistable mechanism design can be achieved by understanding their bistable behavior. This paper presents bistable compliant mechanisms whose pseudo-rigid-body models (PRBM) are four-bar mechanisms with a torsional spring. Stable and unstable equilibrium positions are calculated for such four-bar mechanisms, defining their bistable behavior for all possible permutations of torsional spring locations. Finite Element Analysis (FEA) and simulation is used to illustrate the bistable behavior of a compliant mechanism with a straight compliant member, using stored energy plots. These results, along with the four-bar and the compliant mechanism information, can then be used to design a bistable compliant mechanism to meet specified requirements.

A Simple Transversely Isotropic Hyperelastic Constitutive Model Suitable for Finite Element Analysis of Fiber Reinforced Elastomers

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Leslee W. Brown ◽  
Lorenzo M. Smith
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Energy Function ◽  
Strain Energy ◽  
Strain Energy Function ◽  
Transversely Isotropic ◽  
Material Model ◽  
Fiber Reinforced ◽  
Element Analysis ◽  
Material Tests

A transversely isotropic fiber reinforced elastomer’s hyperelasticity is characterized using a series of constitutive tests (uniaxial tension, uniaxial compression, simple shear, and constrained compression test). A suitable transversely isotropic hyperelastic invariant based strain energy function is proposed and methods for determining the material coefficients are shown. This material model is implemented in a finite element analysis by creating a user subroutine for a commercial finite element code and then used to analyze the material tests. A useful set of constitutive material data for multiple modes of deformation is given. The proposed strain energy function fits the experimental data reasonably well over the strain region of interest. Finite element analysis of the material tests reveals further insight into the materials constitutive nature. The proposed strain energy function is suitable for finite element use by the practicing engineer for small to moderate strains. The necessary material coefficients can be determined from a few simple laboratory tests.

Finite Element Analysis of the Fine Blanking Process for Seat Recliner Plate Holder of Recreation Vehicle

2014 ◽  
Vol 1025-1026 ◽  
pp. 391-394
Author(s):  
Jong Deok Kim ◽  
Young Moo Heo
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Good Accuracy ◽  
Stress And Strain ◽  
Outer Contour ◽  
Element Analysis ◽  
Fine Blanking ◽  
Complex Part ◽  
The Finite Element Analysis ◽  
Blanking Process

In this paper, the finite element analysis (FEA) of the fine blanking process was conducted for the seat recliner plate holder of recreation vehicle. Because the plate holder was a complex part with the various dimple shapes, it was formed and blanked with a three-station progressive fine blanking tool. The fine blanking tool was optimally designed, manufactured and performed the fine blanking experiments. The shear surface of the outer contour, the stress and strain of the part, and the loads of the tool elements were estimated by the results of the fine blanking simulation. Because the plate holder samples from fine blanking experiments had the good accuracy of the dimples’ position and dimension, it would be noticed the fine blanking simulation was conducted without error.

Finite Element Analysis by Using Hyper-Elastic Properties for Rubber Component

2011 ◽  
Vol 488-489 ◽  
pp. 190-193
Author(s):  
Chang Su Woo ◽  
Hyun Sung Park ◽  
Wae Gi Shin
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Energy Function ◽  
Strain Energy ◽  
Strain Energy Function ◽  
Element Analysis ◽  
Energy Functions ◽  
Hyper Elastic ◽  
Rubber Component ◽  
Strain Energy Functions

The material modeling of hyper-elastic properties in rubber is generally characterized by the strain energy function. The strain energy functions have been represented either in term of the strain in variants that are functions of the stretch ratios, or directly in terms of the principal stretch. Successful modeling and design of rubber components relies on both the selection of an appropriate strain energy function and an accurate determination of material constants in the function. Material constants in the strain energy functions can be determined from the curve fitting of experimental stress-strain data. The uniaxial tension, equi-biaxial tension and pure shear test were performed to acquire the constants of the strain energy functions which were Mooney-Rivlin and Ogden model. Nonlinear finite element analysis was executed to evaluate the behavior of deformation and strain distribute by using the commercial finite element code. Also, the fatigue tests were carried out to obtain the fatigue failure. Fatigue failure was initiated at the critical location was observed during the fatigue test of rubber component, which was the same result predicted by the finite element analysis.

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