Mixed Mode Fracture in Electronic Packages

1996 ◽  
Vol 445 ◽  
Author(s):  
W. O. Soboyejo ◽  
V. Sinha ◽  
V. Kenner
Keyword(s):  
Fracture Toughness ◽  
Mixed Mode ◽  
Mode I ◽  
Mode Ii ◽  
Mixed Mode Fracture ◽  
Electronic Packages ◽  
Mixed Mode Loading ◽  
Molding Compound ◽  
Mode Fracture ◽  
Mode Ii Fracture Toughness

AbstractIn this paper, mixedmode (mode I + mode II) fracture toughness data are presented for the prediction of molding compound (silica filled epoxy resin) failure. The stresses necessary to cause the package cracking under mixed mode loading are experimentally determined. Measured toughness values are presented as a function of modemixity and temperature

Mixed Mode I/II Fracture and Fatigue Crack Growth Along 63Sn-37Pb Solder/Brass Interface

2000 ◽  
Author(s):  
H. Nayeb-Hashemi ◽  
Pinghu Yang
Keyword(s):  
Fracture Toughness ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Fracture Surface ◽  
Crack Growth ◽  
Mixed Mode ◽  
Mode I ◽  
Mode Ii ◽  
Mixed Mode Loading ◽  
Solder Layer

Abstract Solder joints are extensively used in electronic packaging. They provide critical electrical and mechanical connections. Single edge notched sandwich specimens, which were made of two blocks of brass joined with a 63Sn-37Pb solder layer, were prepared for fatigue and fracture study of the joint under mixed mode loading. Mode I and mixed mode I/II fracture toughness, fatigue crack thresholds, and fatigue crack growth rates (FCGR) were measured at room temperature using a four point bending test setup. It was found that the fracture toughness of the joint increased and FCGR decreased upon the introduction of mode II component. The interface fracture toughness was higher than that of reported for pure solder. The data of FCGR correlated well with the power law relation of da / dN = C* (ΔG)m. It was also observed that both fracture toughness and FCGR were a function of thickness of solder layer. When the solder layer thickness increased from 0.1mm to 1.0mm, the fracture toughness decreased substantially and FCGR increased slightly. For mode I loading, fatigue crack propagated inside the solder layer. However, for mixed mode loading, once a crack initiated, it changed its direction toward the interface and then propagated along the interface. These observations were related to local mode I and mode II stress fields. Fracture surface showed sign of rubbing under mixed mode loading with elongated cavities at the crack tip. However, under mode I loading, fracture surface was covered with equi-ax voids.

A Micromechanics Based Representation of Combined Mode I and II Toughness of Brittle Materials and Interfaces

1993 ◽  
Vol 115 (1) ◽  
pp. 101-105 ◽  
Author(s):  
J. Ahmad
Keyword(s):  
Experimental Data ◽  
Fracture Toughness ◽  
Brittle Materials ◽  
Mode I ◽  
Mode Ii ◽  
Mode Fracture ◽  
Bimaterial Interfaces ◽  
Mode Ii Fracture Toughness ◽  
Micromechanics Modeling ◽  
Combined Mode

The work of Evans and Hutchinson (1989) on micromechanics modeling of combined mode fracture is used as the basis for proposing an expression for combined Mode I and Mode II fracture toughness of brittle monolithic materials as well as bimaterial interfaces. The results of the proposed expression are compared with experimental data.

Evaluation of Generalized MTS Criterion for Mixed-Mode Fracture of Polyurethane Materials

2013 ◽  
Vol 577-578 ◽  
pp. 117-120 ◽  
Author(s):  
Radu Negru ◽  
Liviu Marşavina ◽  
Hannelore Filipescu
Keyword(s):  
Mixed Mode ◽  
Full Range ◽  
Experimental Results ◽  
Mode I ◽  
Mode Ii ◽  
Mixed Mode Fracture ◽  
Pure Mode ◽  
Bend Specimen ◽  
Mode Fracture ◽  
Fracture Tests

Using the asymmetric semi-circular bend specimen (ASCB) a set of mixed-mode fracture tests were carried out in the full range from pure mode I to pure mode II. The tests were conducted on two polyurethane materials characterized by different properties. The fracture parameters were obtained from experiments and are compared with the predictions based on the generalized MTS criterion (GMTS). The agreement between the experimental results and those predicted based on the GMTS criterion is discussed finally.

scholarly journals Analysis of Mixed-Mode I/II/III Fracture Toughness Based on a Three-Point Bending Sandstone Specimen with an Inclined Crack

2021 ◽  
Vol 11 (4) ◽  
pp. 1652
Author(s):  
Xin Pan ◽  
Jiuzhou Huang ◽  
Zhiqiang Gan ◽  
Shiming Dong ◽  
Wen Hua
Keyword(s):  
Fracture Toughness ◽  
Mixed Mode ◽  
Mode I ◽  
Mixed Mode Fracture ◽  
Pure Mode ◽  
Inclined Crack ◽  
Tangential Strain ◽  
Mode Fracture ◽  
Fracture Parameters ◽  
T Stress

The crack-propagation form may appear as an arbitrary mixed-mode fracture in an engineering structure due to an irregular internal crack. It is of great significance to research the mixed-mode fracture of materials with cracks. The coupling effect of multiple variables (crack height ratio, horizontal deflection angle and vertical deflection angle) on fracture parameters such as the stress intensity factors and the T-stress are the key points in this paper. A three-point bending specimen with an inclined crack was proposed and used to conduct mixed-mode fracture research. The fracture parameters were obtained by finite element analysis, and the computed results showed that the pure mode I fracture and mixed-mode fractures (mode I/II, mode I/III and mode I/II/III) can be realized by changing the deflection angles of the crack. The pure mode I and the mixed-mode fracture toughness of sandstone were obtained by a series of mixed-mode fracture experiments. The experimental results were analyzed with the generalized maximum tangential strain energy density factor criterion considering T-stress. The results showed that the non-singular term T-stress in the fracture parameters cannot be ignored in any mixed-mode fracture research, and the generalized maximum tangential strain energy density factor criterion considering T-stress can better predict the mixed-mode fracture toughness than other criteria.

The influence of temperatures on mixed-mode (I + II) and mode-II fracture toughness of sandstone

2018 ◽  
Vol 189 ◽  
pp. 51-63 ◽  
Author(s):  
Gan Feng ◽  
Yong Kang ◽  
Feng Chen ◽  
Yi-wei Liu ◽  
Xiao-chuan Wang
Keyword(s):  
Fracture Toughness ◽  
Mixed Mode ◽  
Mode I ◽  
Mode Ii ◽  
Mode Ii Fracture ◽  
Mode Ii Fracture Toughness

Mixed Mode Fracture Toughness of Engineering Materials

1995 ◽  
Vol 117 (4) ◽  
pp. 391-394 ◽  
Author(s):  
S. V. Kamat ◽  
J. P. Hirth
Keyword(s):  
Fracture Toughness ◽  
Mixed Mode ◽  
Mechanistic Model ◽  
Void Formation ◽  
Mixed Mode Fracture ◽  
Second Phase ◽  
Mixed Mode Loading ◽  
Mode Fracture ◽  
Second Phase Particles ◽  
Engineering Materials

The effect of mixed mode loading on the fracture toughness of engineering materials is rationalized in terms of the operative fracture mechanism as well as the deformation field ahead of the crack tip. It was found that mixed mode fracture is of utmost importance in materials which fail by stable ductile fracture caused by second phase particles, since in such materials there is a significant reduction in fracture toughness on mixed-mode loading. An autocatalytic shear localization-void formation mechanistic model was found to qualitatively explain the mixed mode fracture behavior in such materials.

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