Abstract

A finite element model was developed to study adhesion of elastic-plastic microcontacts in a previous investigation. An interesting result was the identification of two distinct separation modes, i.e. brittle and ductile separation. In the current study, that model is used to conduct a series of simulations to determine the influence of four nondimensional parameters (including the maximum load parameter) on the contact and on the separation modes. The results show that the parameter S (the ratio of the theoretical stress to the hardness) and δƒ/δc (representing the loading level) are the most important. Smaller S can only lead to brittle separation, while larger S can cause either separation mode depending on δƒ/δc. Ductile separation is more likely to occur at smaller δƒ/δc and brittle separation at greater δƒ/δc. The transition between the two separation modes occurs at about S = 1.2 (for δƒ/δc = 30) which corresponds to the theoretical stress for adhesion being 20% greater than the hardness. This result is qualitatively similar to the existing simplified analytical models, in that the adhesion energy, the hardness, and the loading level play important roles in the occurrence of ductile separation. However, there are important quantitative differences. Comparisons are also made with molecular dynamics simulations of a contact and with a fracture mechanics model of crack propagation.

Notes

Originally published in Journal of Applied Physics, v.103, no.6 (2008). doi:10.1063/1.2874434

Keywords

adhesion, brittleness, cracks, ductile fracture, finite element analysis, hardness, mechanical contact, molecular dynamics method, plastics

Subject Categories

Contact mechanics, Electric switchgear, Microelectronics

Disciplines

Electrical and Electronics | Nanoscience and Nanotechnology

Publisher

American Institute of Physics

Publication Date

2008

Rights Information

Copyright 2008

Rights Holder

American Institute of Physics

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Additional Files

figure1.zip (33 kB)
Figure 1 - high resolution image
figure2.zip (2836 kB)
Figure 2- high resolution image
figure3.zip (724 kB)
Figure 3 - high resolution image
figure4.zip (725 kB)
Figure 4 - high resolution image
figure5.zip (567 kB)
Figure 5 - high resolution image
figure6.zip (624 kB)
Figure 6 - high resolution image
figure7.zip (471 kB)
Figure 7 - high resolution image
figure8.zip (488 kB)
Figure 8 - high resolution image

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