scholarly journals Experimental and Numerical Study on Fracture Characteristics of Interface between In Situ Engineered Cementitious Composites and Steel Deck

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Weiwei Han ◽  
Shuyin Wu ◽  
Xue Gao ◽  
Xinyao Zong ◽  
Jingsong Shan
Keyword(s):  
Fracture Toughness ◽  
Energy Release ◽  
Fracture Criterion ◽  
Hydrodynamic Pressure ◽  
Bimaterial Interface ◽  
Release Rates ◽  
Blister Test ◽  
Energy Release Rates ◽  
Mixed Fracture ◽  
Steel Deck

In this study, engineered cementitious composite (ECC) is used as the pavement of orthotropic steel deck bridge and an epoxy adhesive is used to achieve wet-bonding between the steel deck and cast-in-place ECC. To investigate the fracture properties of bimaterial interface, the double cantilever beam (DCB) and 4-point end notched flexure (4ENF) specimens were used to obtain the fracture toughness, and virtual crack closure technology (VCCT) was used to calculate the energy release rates. A mixed fracture criterion was also established based on the blister test in this study. In addition, for the phenomena of water accumulation in the interface cracks, the hydrodynamic pressure under load was evaluated with a two-way fluid-solid coupling model and the propagation mechanism of cracks at the water-bearing interface was explored. The results showed that the energy release rates at the crack front showed obvious nonuniform distribution characteristics. The blister test indicated that a mixed fracture was in good agreement with the linear fracture criterion. The fracture effect produced by the hydrodynamic pressure of the interfacial water-bearing crack was far less than the fracture toughness of the interface, which indicated that the hydrodynamic pressure could hardly destroy the interface at one time but might cause the erosion fatigue damage of the interface.

On Energy Release Rates and Configurational Forces for Interfacial Propagating Cracks: A Lattice Approach With a Brittle Erosion Technique

2016 ◽  
Vol 84 (2) ◽  
Author(s):  
Amir Mohammadipour ◽  
Kaspar Willam
Keyword(s):  
Energy Release ◽  
Interface Crack ◽  
Driving Forces ◽  
Configurational Forces ◽  
Bimaterial Interface ◽  
Release Rates ◽  
Material Forces ◽  
Energy Release Rates ◽  
Crack Tips ◽  
Lattice Approach

A numerical 2D lattice approach with an erosion algorithm is employed to analyze bimaterial interface fracture quantities in brittle heterogeneous materials in the context of linear elastic fracture mechanics (LEFM). The concept of configurational force is elucidated and the importance of nodal configurational changes in a mesh where no stress–strain analyses are needed is investigated. Three fracture problems, i.e., an infinite panel with a bi-material interface crack, a double-lap shear test, and a prenotched four-point bending masonry beam are then considered. Validated by analytical solutions, the lattice model uses two distinct postprocessing approaches to derive the energy release rates and configurational forces directly at bimaterial interface crack tips. While the first method takes advantage of the change of the lattice mesh's global stiffness matrix before and after crack growth without any stress–strain calculations to obtain crack tip driving forces, the second approach analyzes the configurational forces opposing the crack tip motion using the Eshelby stress tensor and local force balance law in cracked and heterogeneous domains. It is demonstrated that the discrete material forces at crack tips are closely equal to the tip driving forces for the three fracture problems, confirming that the lattice is an appropriate numerical tool to analyze fracture properties of evolving interface cracks. Satisfying C1 continuity by including rotational displacements for frame struts, there is also no need for the lattice to update interior computational points in the mesh to eliminate spurious material forces away from the tip.

Analysis of film residual stress on a of 4-point bend test for thin film adhesion

2005 ◽  
Vol 875 ◽  
Author(s):  
Sassan Roham ◽  
Timothy Hight
Keyword(s):  
Residual Stress ◽  
Energy Release ◽  
Semiconductor Industry ◽  
Finite Size ◽  
Bimaterial Interface ◽  
Release Rates ◽  
Interface Adhesion ◽  
Crack Penetration ◽  
Energy Release Rates ◽  
Point Bend

AbstractThe four-point bend (4PB) test has emerged as a method of choice in semiconductor industry for obtaining bimaterial interface adhesion data. When measuring the interface adhesion using 4PB test, it is essential to obtain a crack through the interface of interest. The deposited films, however, posses intrinsic and extrinsic stresses which affect the ratio between energy release rates for interface cracking and crack penetration. Crack penetration and deflection at a bimaterial interface and the role of residual stress has been broadly studied before. However, the results are based on asymptotic analysis regarding interface between two semi-infinite half spaces, where the results do not directly account for boundary conditions and finite size effects of an actual test specimen. In this paper, we look at the role these residual stresses play on the competition between deflection and penetration energy release rates of a bimaterial interface and the extent of which the previous assumption of two semi-infinite media can be accepted.

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