scholarly journals New CZM for Interfacial Crack Growth

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Huifen Peng ◽  
Yujie Song ◽  
Ye Xia
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Crack Growth ◽  
Interface Crack ◽  
Interfacial Crack ◽  
Structure Design ◽  
Zone Model ◽  
Simulation Results ◽  
The Impact ◽  
Element Method

The cohesive zone model (CZM) has been widely used for numerical simulations of interface crack growth. However, geometrical and material discontinuities decrease the accuracy and efficiency of the CZM when based on the conventional finite element method (CFEM). In order to promote the development of numerical simulation of interfacial crack growth, a new CZM, based on the wavelet finite element method (WFEM), is presented. Some fundamental issues regarding CZM of interface crack growth of double cantilever beam (DCB) testing were studied. The simulation results were compared with the experimental and simulation results of CFEM. It was found that the new CZM had higher accuracy and efficiency in the simulation of interface crack growth. At last, the impact of crack initiation length and elastic constants of material on interface crack growth was studied based on the new CZM. These results provided a basis for reasonable structure design of composite material in engineering.

Numerical Simulation of Crack Growth of Composite Structure Based on XFEM

2012 ◽  
Vol 598 ◽  
pp. 366-369 ◽  
Author(s):  
Yong Qiang Zhong
Keyword(s):  
Numerical Simulation ◽  
Finite Element Method ◽  
Finite Element ◽  
Crack Growth ◽  
Composite Structure ◽  
Initial Crack ◽  
Difficult Problem ◽  
Structure Design ◽  
Bending Test ◽  
Element Method

The basic principle and technique of a new and effective extended finite element method is introduced first in the paper. Compared with classical finite element method, the crack growth can be simulated by XFEM without making the crack surface associated to the mesh and without remeshing after crack growth. On the basis it is applied to analyze difficult problem of fracture and crack growth mechanism of composite pavement structural. By three-point bending test of composite structural beam, the whole process of initial crack and the crack growth of composite pavement structure is analyzed by numerical simulation. It can be divided into four key stages from cracking to crack reflection and each stage is presented by tensile stress and SATUSXFEM. The research results can provide important reference for composite structure design and proposed control countermeasure.

A Fracture Mechanics Based Parametric Study of the Copper-to-Copper Direct Thermo-Compression Bonded Interface Using Finite Element Method

2013 ◽  
Author(s):  
Ah-Young Park ◽  
Satish Chaparala ◽  
Seungbae Park
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Parametric Study ◽  
Initial Crack ◽  
Bonding Interface ◽  
Interface Condition ◽  
Large Temperature ◽  
Bonded Interface ◽  
The Impact ◽  
Element Method

Through-silicon via (TSV) technology is expected to overcome the limitations of I/O density and helps in enhancing system performance of conventional flip chip packages. One of the challenges for producing reliable TSV packages is the stacking and joining of thin wafers or dies. In the case of the conventional solder interconnections, many reliability issues arise at the interface between solder and copper bump. As an alternative solution, Cu-Cu direct thermo-compression bonding (CuDB) is a possible option to enable three-dimension (3D) package integration. CuDB has several advantages over the solder based micro bump joining, such as reduction in soldering process steps, enabling higher interconnect density, enhanced thermal conductivity and decreased concerns about intermetallic compounds (IMC) formation. Critical issue of CuDB is bonding interface condition. After the bonding process, Cu-Cu direct bonding interface is obtained. However, several researchers have reported small voids at the bonded interface. These defects can act as an initial crack which may lead to eventual fracture of the interface. The fracture could happen due to the thermal expansion coefficient (CTE) mismatch between the substrate and the chip during the postbonding process, board level reflow or thermal cycling with large temperature changes. In this study, a quantitative assessment of the energy release rate has been made at the CuDB interface during temperature change finite element method (FEM). A parametric study is conducted to analyze the impact of the initial crack location and the material properties of surrounding materials. Finally, design recommendations are provided to minimize the probability of interfacial delamination in CuDB.

Robust Stress Check Formula of Lifting Padeye

2010 ◽  
Vol 54 (01) ◽  
pp. 34-40
Author(s):  
Zhou Bo ◽  
Liu Yujun ◽  
Ji Zhuoshang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Accurate Method ◽  
Offshore Structures ◽  
Structure Design ◽  
Stress Calculation ◽  
Check Method ◽  
External Loads ◽  
Actual Stress ◽  
Element Method

Lifting padeyes are widely used in the construction of offshore structures and ships. It has been shown that the traditional check method cannot reflect the realistic value and distribution of actual stress on the padeyes. A more accurate method for the padeye stress calculation is essential and important for promoting the safety of the padeyes. In this paper, a new check formula is proposed based on the analysis of deformation and external loads distribution on lifting padeyes. The results of finite element method and the solutions of traditional check formula and new check formula are compared. It is shown that, by applying the stress check formula derived in the paper, the value and the location of the dangerous stresses occurred can be evaluated easily and exactly. The safe reliability of structure design can be improved significantly.

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