Finite strain thermomechanical material characterization of adhesives used in automotive electronics for quantitative finite element simulations

2014 ◽  
Author(s):  
B. Ozturk ◽  
P. Gromala ◽  
C. Silber ◽  
K. M. B. Jansen ◽  
L. J. Ernst
Keyword(s):  
Finite Element ◽  
Material Characterization ◽  
Finite Strain ◽  
Finite Element Simulations ◽  
Automotive Electronics

scholarly journals Correlation of Global Quantities at Material Characterization of Pressure-Sensitive Materials Using Sharp Indentation Testing

Lubricants ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 29
Author(s):  
Carl F. O. Dahlberg ◽  
Jonas Faleskog ◽  
Per-Lennart Larsson
Keyword(s):  
Finite Element ◽  
Material Characterization ◽  
Pressure Sensitivity ◽  
Pressure Sensitive ◽  
The Mean ◽  
Sharp Indentation ◽  
Von Mises ◽  
Von Mises Plasticity ◽  
Hardness Values

Correlation of sharp indentation problems is examined theoretically and numerically. The analysis focuses on elastic-plastic pressure-sensitive materials and especially the case when the local plastic zone is so large that elastic effects on the mean contact pressure will be small or negligible as is the case for engineering metals and alloys. The results from the theoretical analysis indicate that the effect from pressure-sensitivity and plastic strain-hardening are separable at correlation of hardness values. This is confirmed using finite element methods and closed-form formulas are presented representing a pressure-sensitive counterpart to the Tabor formula at von Mises plasticity. The situation for the relative contact area is more complicated as also discussed.

Incompressibility and mesh sensitivity analysis in finite element simulation of rubbers

2016 ◽  
Vol 7 (1) ◽  
pp. 7-12 ◽  
Author(s):  
D. Huri
Keyword(s):  
Finite Element ◽  
Material Characterization ◽  
Numerical Stability ◽  
Material Parameters ◽  
Linear Finite Element ◽  
Element Simulation ◽  
Finite Element Calculations ◽  
Mesh Density ◽  
Rubber Component

Non-linear finite element calculations are indispensable when important information of the material response under load of a rubber component is desired. Although the material characterization of a rubber component is a demanding engineering task, the changing contact range between the parts and the incompressibility behaviour of the rubber further increase the complexity of the investigations. In this paper the effects of the choice of the numerical material parameters (e.g. bulk modulus) are examined with regard to numerical stability, mesh density and calculation accuracy. As an example, a rubber spring is chosen where contact problem is also handled.

Characterization of delamination-type damages in composite laminates using guided wave visualization and air-coupled ultrasound

2016 ◽  
Vol 16 (2) ◽  
pp. 142-152 ◽  
Author(s):  
Rabi S Panda ◽  
Prabhu Rajagopal ◽  
Krishnan Balasubramaniam
Keyword(s):  
Finite Element ◽  
Composite Laminates ◽  
Three Dimensional ◽  
Guided Wave ◽  
Finite Element Simulations ◽  
Wave Refraction ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Lamb Wave Propagation

This article reports on the characterization of delamination damages in composite laminates using wave visualization method. A combination of plate-guided ultrasound and air-coupled ultrasonics is used to locate and visualize delaminations. The study focuses on the physics of Lamb wave propagation and interaction with delaminations at various through-thickness locations and positions. Three-dimensional finite element simulations are used to study, in detail, the changes in wave features such as mode velocity, wavelength and wave refraction in the delamination region. These wave features provide information on the location, position and orientation of the delamination. These studies are validated by experimental measurements. The influence of position of source and delamination on wave refraction in the delamination region is examined. This method also correlates the results obtained from experiments and finite element simulations to theoretical dispersion curves in order to distinctly determine the delamination location.

Nonlocal Damage Modeling of Solder Joint Failure Under Thermomechanical Cyclic Loading

2021 ◽  
Author(s):  
Youssef Maniar ◽  
Alexander Kabakchiev ◽  
Marta Kuczynska ◽  
Masoomeh Bazrafshan ◽  
Peter Binkele ◽  
...  
Keyword(s):  
Finite Element ◽  
Cyclic Loading ◽  
Solder Joint ◽  
End Of Life ◽  
Damage Evolution ◽  
Life Prediction ◽  
Finite Element Simulations ◽  
Automotive Electronics ◽  
Localization Algorithm ◽  
Nonlocal Damage

Abstract The increasing electrified mobility poses a challenge on reliability prediction of automotive electronics, especially when safety systems are concerned. The use of finite element simulation for accurate end-of-life prediction of automotive electronic devices under harsh environmental loading condition is getting increasingly significant. In particular, solder interconnection failure is in focus when subjected to thermomechanical loads. During cyclic loading, the initial deformation behavior and subsequent solder degradation can be modeled within finite element simulations using material damage coupled deformation models. Such models employ the calculation of an internal damage state variable at integration point level as functions of time, temperature and governing stress-strain state. In this work, a thermodynamic consistent implicit nonlocal damage formulation is presented. This modeling approach allows absolute end-of-life prediction of different solder joint geometries under thermomechanical cyclic loading within finite element simulations. The presented nonlocal damage model consists of damage evolution with strain and stress state dependencies, such as stress multiaxiality. Furthermore, a numerical de-localization algorithm is proposed, in order to avoid instability of damage evolution caused by finite element mesh dependency. Finally, the advantages and implications of the nonlocal damage approach are discussed based on simulations of damage evolution in multiple solder joints of a QFN48 package under combined cyclic thermal and mechanical 4-point bending loading.

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