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131.
C. KANCHANOMAI Y. MUTOH 《Fatigue & Fracture of Engineering Materials & Structures》2007,30(5):443-457
In modern electronic packaging, especially surface mount technology (SMT), thermal strain is usually induced between components during processing, and in service, by a mismatch in the thermal expansion coefficients. Since solder has a low melting temperature and is softer than other components in electronic packaging, most of the cyclic stresses and strains take place in the solder. Fatigue crack initiation and fatigue crack propagation are likely to occur in the solder even when the cyclic stress is below the yield stress. It is an objective of this research to study the behaviour of fatigue crack initiation and propagation in both lead‐containing solder (63Sn‐37Pb), and lead‐free solders (Sn‐3.5Ag). The effect of alloying (Cu and Bi addition), frequency, tensile hold time and temperature on low cycle fatigue (LCF) behaviour of the solders is discussed. Mechanisms of LCF crack initiation and propagation are proposed and LCF life prediction, based on the various models, is carried out. 相似文献
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Olli Salmela Klas Andersson Altti Perttula Jussi Särkkä Markku Tammenmaa 《Quality and Reliability Engineering International》2007,23(4):415-429
In this paper, the solder attachment fatigue model created by Werner Engelmaier is re‐calibrated in order to make it applicable in conjunction with leadless, lead‐free solder attachments. Sn3.8Ag0.7Cu solder attached ball‐grid‐array components are addressed to three thermal cycling test profiles. Based on the results, both physical and statistical parameters are obtained and compared with the values relevant to tin–lead solder assemblies. The validity of the statistical distribution selection (two‐parameter Weibull) is studied. Acceleration factors correlating different test profiles are obtained, and they are found to be only weakly dependent on the test vehicle type. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
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M. Kobayashi M. Mukai H. Takahashi N. Ohno T. Kawakami T. Ishikawa 《International journal for numerical methods in engineering》2003,58(10):1523-1543
This paper describes the implicit integration and consistent tangent modulus of an inelastic constitutive model with transient and steady strain rates, both of which are time‐ and temperature‐dependent; the transient rate is influenced by the evolution of back stress decomposed into parts, while the steady rate depends only on applied stress and temperature. Such a non‐unified model is useful for high‐temperature structural analysis and is practical owing to the ease in determining material constants. The implicit integration is shown to result in two scalar‐valued coupled equations, and the consistent tangent modulus is derived in a quite versatile form by introducing a set of fourth‐rank constitutive parameters into the discretized evolution rule of back stress. The constitutive model is, then, implemented in a finite element program and applied to a lead‐free solder joint analysis. It is demonstrated that the implicit integration is very accurate if the multilinear kinematic hardening model of Ohno and Wang is employed, and that the consistent tangent modulus certainly affords quadratic convergence to the Newton–Raphson iteration in solving nodal force equilibrium equations. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
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