Equivalent Principle of Time‐Temperature‐Strain Rate for Poisson's Ratio of Composite Solid Propellant

2019 ◽  
Vol 45 (1) ◽  
pp. 118-127
Author(s):  
Xuan Lv ◽  
Wei Yong Zhou ◽  
Zhi Bin Shen ◽  
Hui Ru Cui
Keyword(s):  
Strain Rate ◽  
Poisson’S Ratio ◽  
Solid Propellant ◽  
Poisson's Ratio ◽  
Composite Solid Propellant ◽  
Temperature Strain ◽  
Composite Solid

The Effects of Temperature, Strain Rate, and Aging on the Poisson’s Ratio of SAC Lead Free Solders

2018 ◽  
Author(s):  
K. M. Rafidh Hassan ◽  
Mohammad S. Alam ◽  
Munshi Basit ◽  
Jeffrey C. Suhling ◽  
Pradeep Lall
Keyword(s):  
Finite Element ◽  
Strain Rate ◽  
Poisson’S Ratio ◽  
Poisson's Ratio ◽  
Lead Free ◽  
Uniaxial Tensile ◽  
Automatic Data ◽  
Effects Of Temperature ◽  
Lead Free Solders ◽  
Temperature Strain

In this study, we have conducted a combined numerical and experimental study on the Poisson’s ratio of SAC lead free solders. The Poisson’s ratio (PR) is one of the basic mechanical properties used in many material constitutive models. Although often not measured, it is important property in many finite element method (FEM) calculations. The value of the Poisson’s ratio of SAC lead free solders is relatively unexplored compared to other material properties, and for FEA simulations it is typically assumed to be v = 0.3. In the current work, we have shown the effects of the chosen value of the solder joint Poisson’s ratio on the finite element results for BGA components subjected to thermal cycling. In the finite element models, the reliability predictions were based on the Morrow-Darveaux energy-based fatigue model. Several sizes (5, 10, 15 mm) of PBGA components with SAC305 solder joints with 0.4 and 0.8 mm spacing were modeled. The packages were subjected to a time dependent cyclic temperature distribution from −40 to 125 °C. The package assemblies were assumed to be in a stress-free state at 25 °C (room temperature), with no residual stresses induced in the manufacturing process. The simulation results have demonstrated that for specified range of Poisson’s ratio values of 0.15 < v < 0.40, the solder Plastic Work varied over 20% and the Predicted Reliability Varied over 50%. To determine the actual Poisson’s ratio experimentally, uniaxial tensile stress-strain tests were carried out on SAC305 (96.5Sn3.0Ag0.5Cu) specimens using a micro tension/torsion testing machine with two strain rates (0.0001, and 0.00001 (sec−1)), four testing temperatures (T = 25, 50, 75, 100 °C), and several durations of prior aging at T = 125 °C. Deformations and strains in axial and transverse directions were measured using strain gages with automatic data acquisition from LabVIEW software. The recorded transverse strain vs. axial strain data were then fit with a linear regression analysis to determine the Poisson’s ratio values. A test matrix of experiments was developed to study the effects of temperature, strain rate, alloy composition, and solidification cooling profile on the value of solder Poisson’s ratio. The Poisson’s ratio was found to increase with increasing temperature, and decrease with increasing strain rate. Using a slower solidification cooling profile led to an increase in the solder Poisson’s ratio value. Finally, the microstructural coarsening that occurs during isothermal aging lead to an increase in the Poisson’s ratio.

Modelling the yield stress and the Poisson’s ratio of glassy polymers

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Alberto D’Amore ◽  
Luigi Grassia ◽  
Domenico Acierno
Keyword(s):  
Strain Rate ◽  
Yield Stress ◽  
Linear Dependence ◽  
Poisson’S Ratio ◽  
Glassy Polymers ◽  
Poisson's Ratio ◽  
Viscoelastic Response ◽  
Relaxation Behaviour ◽  
Volume Relaxation ◽  
Temperature Strain

AbstractWe have recently reported that the volumetric as well as the viscoelastic intricacies of mechanically stimulated glasses can be predicted by coupling the structural relaxation kinetics and viscoelastic response [1, 2, 3].Here, it will be shown that our approach can be extended to predict the stressstrain behaviour of glassy polymers as function of temperature, strain rate and aging time. In particular, a linear dependence of yield stress on the logarithmic of the strain rate can be obtained, conforming to the classical Eyring-type behaviour. The Poisson’s ratio evolution was obtained from the volume relaxation behaviour highlighting an unexpected correlation between the yield point and the volumetric behaviour.

scholarly journals Research on Creep Constitutive and Numerical Simulation of Composite Solid Propellant

2021 ◽  
Vol 1786 (1) ◽  
pp. 012002
Author(s):  
S.X. Feng ◽  
H.F. Qiang ◽  
Y.X. Liu ◽  
X.R. Wang ◽  
T.J. Geng ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Solid Propellant ◽  
Composite Solid Propellant ◽  
Composite Solid

Effect of time–temperature, strain level and cyclic loading on the complex Poisson’s ratio of asphalt mixtures

2021 ◽  
Vol 294 ◽  
pp. 123564
Author(s):  
Quang Tuan Nguyen ◽  
Hervé Di Benedetto ◽  
Quang Phuc Nguyen ◽  
Thi Thanh Nhan Hoang ◽  
Van Phu Bui
Keyword(s):  
Cyclic Loading ◽  
Poisson’S Ratio ◽  
Asphalt Mixtures ◽  
Strain Level ◽  
Poisson's Ratio ◽  
Complex Poisson’S Ratio ◽  
Temperature Strain
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