Showing papers by "Cheng Yan published in 2001"

Effect of Bond Thickness on Fracture Behaviour in Adhesive Joints

Abstract: To study the effects of bond thickness on the fracture behaviour of adhesive joints, experimental investigation and finite element analysis have been carried out for compact tension (CT) and double-cantilever-beam (DCB) specimens with different bond thickness Fractography and fracture toughness exhibited apparent variations with bond thickness Numerical results indicate that the crack tip stress fields are affected by bond thickness due to the restriction of plastic deformation by the adherends At the same J level, a higher opening stress was observed in the joint with a smaller bond thickness (h) Beyond the crack tip region, a self-similar stress field can be described by the normalized loading parameter, J/hσ0 The relationship between J and crack tip opening displacement, δ, is dependent on the bond thickness The strong dependence of toughness upon bond thickness is a result of the competition between two different fracture mechanisms For small bond thickness, toughness is linearly propo

Effect of bond thickness on fracture behaviour in adhesive joints

Abstract: To study the effects of bond thickness on the fracture behaviour of adhesive joints, experimental investigation and finite element analysis have been carried out for compact tension (CT) and double-cantilever-beam (DCB) specimens with different bond thickness. Fractography and fracture toughness exhibited apparent variations with bond thickness. Numerical results indicate that the crack tip stress fields are affected by bond thickness due to the restriction of plastic deformation by the adherends. At the same J level, a higher opening stress was observed in the joint with a smaller bond thickness (h). Beyond the crack tip region, a self-similar stress field can be described by the normalized loading parameter, J/hσ0. The relationship between J and crack tip opening displacement, δ, is dependent on the bond thickness. The strong dependence of toughness upon bond thickness is a result of the competition between two different fracture mechanisms. For small bond thickness, toughness is linearly propo...

Nonlinear analysis of plastic ball grid array solder joints

Abstract: A nonlinear finite element analysis was carried out to investigate the viscoplastic deformation of solder joints in a ball grid array (BGA) package under temperature cycling The effects of constraint on printed circuit board (PCB) and stiffness of substrate on the deformation behavior of the solder joints were also studied A relative damage stress was adopted to analyze the potential failure sites in the solder joints The results indicated that high inelastic strain and strain energy density were developed in the joints close to the package center On the other hand, high constraint and high relative damage stress were associated with the joint closest to the edge of the silicon chip which was regarded as the most susceptible failure site if cavitation instability is the dominant failure mechanism Increasing the external constraint on PCB causes a slight increase in stress triaxiality $$ \left( {\sigma _m /\sigma _{eq} } \right) $$ and relative damage stress in the joint closest to the edge of the silicon die The relative damage stress is not sensitive to the Young's modulus of the substrate