Fracture Mechanics of Composites With Residual Thermal Stresses

1997 ◽  
Vol 64 (4) ◽  
pp. 804-810 ◽  
Author(s):  
J. A. Nairn
Keyword(s):  
Residual Stresses ◽  
Boundary Conditions ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Thermal Stresses ◽  
Double Cantilever Beam ◽  
Effective Properties ◽  
Displacement Boundary ◽  
Effective Mechanical Properties

The problem of calculating the energy release rate for crack growth in an arbitrary composite in the presence of residual stresses is considered. First, a general expression is given for arbitrary, mixed traction, and displacement boundary conditions. This general result is then applied to a series of specific problems including statistically homogeneous composites under traction or displacement boundary conditions, delamination of double cantilever beam specimens, and microcracking in the transverse plies of laminates. In many examples, the energy release rate in the presence of residual stresses can be reduced to finding the effect of damage on the effective mechanical properties of the composite. Because these effective properties can be evaluated by isothermal stress analysis, the effect of residual stresses on the energy release rate can be evaluated without recourse to any thermal elasticity stress analyses.

Reliability Simulation of Cu/Polymer interface in Fan-out Wafer Level Packaging

2020 ◽  
Vol 2020 (1) ◽  
pp. 000094-000099
Author(s):  
Yuji Okada ◽  
Atsushi Fujii ◽  
Kenta Ono ◽  
Yoshiharu Kariya
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Thermal Stresses ◽  
Material Selection ◽  
Basic Material ◽  
Model Structure ◽  
Critical Energy Release Rate ◽  
Interlayer Dielectric ◽  
Polymer Interface

Abstract In order to improve the performance and reliability of the package, the interlayer dielectric (Polymer) must not be delaminated and materials should not fracture due to thermal stresses during the operation or the manufacturing process. If the reliability of the package can be known in advance by simulation, it can be expected to greatly help in material selection and package design. Firstly, we created material-specific master curves (time–temperature superposition) by considering the measurement results of the Peel Test at the Cu/Polymer interface and the mechanical properties of polymer. The critical Energy Release Rate (𝒢𝒸) could be calculated by its master curve. Secondary, we calculated the Energy Release Rate (𝒢) from Finite Element Analysis (FEA) in the package model structure. Finally, delamination is judged by normalizing 𝒢/𝒢𝒸. This study has made it possible to simulate the delamination possibility of Cu/Polymer interface at arbitrary temperatures and displacement rates from basic material data and FEA analysis of the package model structure.

Effect of Solvent Diffusion on Crack-Tip Fields and Driving Force for Fracture of Hydrogels

2015 ◽  
Vol 82 (8) ◽  
Author(s):  
Nikolaos Bouklas ◽  
Chad M. Landis ◽  
Rui Huang
Keyword(s):  
Boundary Conditions ◽  
Energy Release Rate ◽  
Energy Release ◽  
Crack Growth ◽  
Release Rate ◽  
Crack Tip ◽  
Far Field ◽  
Solvent Diffusion ◽  
Effect Of Solvent ◽  
Transient Energy

Hydrogels are used in a variety of applications ranging from tissue engineering to soft robotics. They often undergo large deformation coupled with solvent diffusion, and structural integrity is important when they are used as structural components. This paper presents a thermodynamically consistent method for calculating the transient energy release rate for crack growth in hydrogels based on a modified path-independent J-integral. The transient energy release rate takes into account the effect of solvent diffusion, separating the energy lost in diffusion from the energy available to drive crack growth. Numerical simulations are performed using a nonlinear transient finite element method for center-cracked hydrogel specimens, subject to remote tension under generalized plane strain conditions. The hydrogel specimen is assumed to be either immersed in a solvent or not immersed by imposing different chemical boundary conditions. Sharp crack and rounded notch models are used for small and large far-field strains, respectively. Comparisons to linear elastic fracture mechanics (LEFM) are presented for the crack-tip fields and crack opening profiles in the instantaneous and equilibrium limits. It is found that the stress singularity at the crack tip depends on both the far-field strain and the local solvent diffusion, and the latter evolves with time and depends on the chemical boundary conditions. The transient energy release rate is predicted as a function of time for the two types of boundary conditions with distinct behaviors due to solvent diffusion. Possible scenarios of delayed fracture are discussed based on evolution of the transient energy release rate.

scholarly journals Energy release rate in the presence of residual and thermal stresses

2015 ◽  
Vol 59 ◽  
pp. 73-78 ◽  
Author(s):  
Jeong Soon Park ◽  
Young Hwan Choi ◽  
Jungdo Kim ◽  
Seyoung Im
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Thermal Stresses

Analysis of Potential Energy Release Rate of Composite Laminate Based on Timoshenko Beam Theory

2007 ◽  
Vol 334-335 ◽  
pp. 513-516
Author(s):  
Kyohei Kondo
Keyword(s):  
Potential Energy ◽  
Energy Release Rate ◽  
Energy Release ◽  
Timoshenko Beam ◽  
Release Rate ◽  
Double Cantilever Beam ◽  
Beam Theory ◽  
Timoshenko Beam Theory ◽  
Beam Specimen ◽  
Cracked Beam

The Timoshenko beam theory is used to model each part of cracked beam and to calculate the potential energy release rate. Calculations are given for the double cantilever beam specimen, which is simulated as two separate beams connected elastically along the uncracked interface.

scholarly journals Computation of mode I strain energy release rate of symmetrical and asymmetrical sandwich structures using mixed finite element

2021 ◽  
Vol 15 (56) ◽  
pp. 229-239
Author(s):  
Amina Mohamed Ben Ali ◽  
Salah Bouziane ◽  
Hamoudi Bouzerd
Keyword(s):  
Finite Element ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Strain Energy ◽  
Strain Energy Release Rate ◽  
Double Cantilever Beam ◽  
Mixed Finite Element ◽  
Strain Energy Release ◽  
Mode I

The use of composite materials is on the rise in different engineering fields, the main advantage of these materials for the aerospace industry is their low weight for excellent mechanical qualities. The analysis of failure modes, such as delamination, of these materials has received great attention from researchers. This paper proposes a method to evaluate the mode I Strain Energy Release Rate (SERR) of sandwich structures. This method associated a two-dimensional mixed finite element with virtual crack extension technique for the analysis of interfacial delamination of sandwich beams. A symmetrical Double Cantilever Beam (DCB) and asymmetrical Double Cantilever Beam (UDCB) have been analyzed in this study.  The comparison of the results obtained by this method and those found in the literature shows efficiency and good precision for the calculation of Strain Energy Release Rate (SERR).

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