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Rate Dependent Fracture along a Silicon/Epoxy Interface Under Mixed-Mode Loading Conditions

Yang, Tianhao and Gandhi, Vatsa and Huang, Rui and Liechti, Kenneth M. (2021) Rate Dependent Fracture along a Silicon/Epoxy Interface Under Mixed-Mode Loading Conditions. International Journal of Solids and Structures . ISSN 0020-7683. doi:10.1016/j.ijsolstr.2021.111129. (In Press)

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This paper describes the development of a dual-actuator loading device that was then used to apply asymmetric, transverse end-displacements to laminated beam specimens (silicon/epoxy/silicon) over a range of separation rates. Measurements of the reaction forces, as well as load-point displacements and rotations, were used to determine the normal and tangential components of the crack tip displacements and the corresponding components of the J-integral. This was made possible because the specimens identically satisfied a balance condition. The resulting data set obtained from experiments conducted at five separation rates at each of five mode-mix phase angles is a testimony to the efficiency of the approach. A mixed-mode beam on elastic foundation analysis established that the stiffness of the normal and shear interactions of the silicon/epoxy interface was independent of the separation rate and mode-mix. Furthermore, the stiffness values thus determined were considerably lower than those based on the bulk behavior of the epoxy in tension and shear. The analysis also allowed the crack growth to be tracked in order to establish its onset and the corresponding critical values of the normal and shear components of the J-integral, along with the corresponding strengths and critical crack tip displacements. For each mode-mix, these critical values increased with the separation rate. This increase in properties is in spite of the glassy nature of the bulk epoxy and further suggests the presence of an interphase region in the epoxy adjacent to the silicon. However, the change of mode-mix was accompanied by a change in local separation rates, leading to non-monotonic behavior in the critical J-integral. Following the onset of crack growth, the application of the transverse end-displacements along radial loading paths resulted in simultaneous changes in the local separation rates and mode-mix, implying a fracture criterion that depends on both mode-mix and rate-dependent damage evolution processes.

Item Type:Article
Related URLs:
URLURL TypeDescription
Gandhi, Vatsa0000-0002-6752-113X
Huang, Rui0000-0003-0328-3862
Additional Information:© 2021 Published by Elsevier Ltd. Received 8 February 2021, Revised 3 June 2021, Accepted 8 June 2021, Available online 10 June 2021. The authors gratefully acknowledge the financial support of this work by the Semiconductor Research Corporation (SRC Task ID: 2886.001). The senior authors (RH and KML) are honored to have this paper included in the special edition celebrating the 70th birthday of Stelios Kyriakides, our colleague and longtime friend (KML). Stelios is a leader in so many ways and an inspiration to most of us, but what I value above all is his friendship and companionship. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: This paper has not been submitted elsewhere.
Funding AgencyGrant Number
Semiconductor Research Corporation2886.001
Subject Keywords:Dual-actuator loading device; Laminated beam specimens; Mixed-mode fracture; Mixed-mode foundation analysis; Rate dependent fracture
Record Number:CaltechAUTHORS:20210622-204127176
Persistent URL:
Official Citation:Tianhao Yang, Vatsa Gandhi, Rui Huang, Kenneth M. Liechti, Rate Dependent Fracture along a Silicon/Epoxy Interface Under Mixed-Mode Loading Conditions, International Journal of Solids and Structures, 2021, 111129, ISSN 0020-7683, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:109534
Deposited By: Tony Diaz
Deposited On:23 Jun 2021 19:10
Last Modified:23 Jun 2021 19:10

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