ANALYSIS OF FREE-EDGE STRESS AND DISPLACEMENT FIELDS IN SCARF JOINTS SUBJECTED TO A UNIFORM CHANGE IN TEMPERATURE |
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Authors: | ZQ Qian & AR Akisanya |
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Affiliation: | Engineering Department, University of Aberdeen, King's College, Aberdeen AB24 3UE, UK |
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Abstract: | The role of free-edge stresses in controlling the initiation of failure from the interface corner of a scarf joint subjected to a uniform change in temperature is examined. In general, the stress field can be expressed by σ ij = Hr λ ?1 + σ ij 0 , where r is the radial distance from the interface corner, λ ? 1 is the order of the stress singularity, H is the intensity of the singularity, and σ ij 0 is a non-singular constant stress. A combination of the finite element method and a path-independent integral is used to evaluate the magnitude of H for two joint configurations: (i) a scarf joint between two long bi-material strips; and (ii) a scarf joint consisting of a thin elastic layer sandwiched between two substrates. The magnitude of H is linearly dependent on a non-dimensional constant function a; the magnitude of a decreases with increasing level of mismatch in the elastic properties of the bonded materials. A comparison between the values of H evaluated by the path-independent integral method and the commonly used extrapolation method indicate that the extrapolation method could be in error by as much as 25%. |
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Keywords: | Stress singularity Thermal stress Bonded joints Failure criteria FEM |
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