Bondline thickness effect on fracture and cohesive zone model of sintered nano silver adhesive joints under end notched flexure tests

Abstract

Bondline thickness effect on fracture behaviors and cohesive zone model (CZM) is an important topic for adhesive joints. In this paper, the fracture and CZM of sintered nano silver adhesive joints are investigated based on end notched flexure (ENF) test. Results show that load versus displacement curves of sintered silver adhesive joints is sensitive to the bondline thickness. With compliance‐based beam method (CBBM), the shearing fracture toughness of sintered silver bonded joints heightens with the increase of bondline thickness, which indicates that shearing fracture toughness is highly dependent on bondline thickness. R curves increase steeply for short equivalent crack length and become plateau for long equivalent crack length. The cracking morphology shows that the cracking paths are mainly interfacial and interlayer types. The bilinear CZM is also presented. The bondline thickness effect on CZM parameter is presented and discussed. The CZM given in this paper can be adopted for reliability analysis in power devices.

Deep neural network aided cohesive zone parameter identifications through die shear test in electronic packaging

“…25 Accordingly, the traction separation law describes the fracture relationship by introducing a critical fracture energy, that is, the critical energy required to break the interface surface. 24 The bilinear traction separation law of the CZM is adopted as shown in Figure 3, which is described as…”

“…where δ 0 and δ f are the characteristic interface slip and maximum interface slip separation, respectively, 24 and k 1 and k 2 are the interface stiffness, which are given as…”

“…The classical CZM model can be used to predict the bonding strength 22,23 and fracture toughness of sintered silver bonding joints [24][25][26] in electronic packaging. For example, Campilho et al 27 conducted a finite element (FE) analysis of the lap shear test based on the traction separation law of CZM and proved that the CZM can provide accurate results of bonding strength.…”

Generalized displacement control technique for mode I/II fracture problems using cohesive zone model within a modified element‐free Galerkin framework

“…CZMs are incorporated into the numerical techniques using the cohesive elements characterized by cohesive or traction–separation laws (TSL). Particularly, CZMs are of special interest for many researchers in adhesive bonded joints because of their ability to anticipate the failure behavior of both brittle and toughened adhesives, as well as thick and thin adhesive layers 36–39 …”

“…Particularly, CZMs are of special interest for many researchers in adhesive bonded joints because of their ability to anticipate the failure behavior of both brittle and toughened adhesives, as well as thick and thin adhesive layers. [36][37][38][39] Belytschko et al 40 analyzed the dynamic fracture in concrete using the CZMs through the EFG framework and proposed that the EFG method is reliable for this task. Klein et al 41 used reproducing kernel particle method (RKPM) and compared several cohesive approaches of that time (bulk and surface cohesive formulations).…”