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- Islam, Md. Shafiqul, 1984-, et al.
(författare)
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Study of Ligament Length Effect on Mode Mix of a Modified In-Plane Shear Test Specimen
- 2016
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Ingår i: Materials Performance and Characterization. - California, USA : American Society for Testing and Materials. - 2379-1365 .- 2165-3992. ; 5:3
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Tidskriftsartikel (refereegranskat)abstract
- Shear fracture toughness is an important material behavior that needs to be determined and considered in many industrial fields. At the same time, shear testing is one of the complex material testing areas where available methods are few, often need special arrangements, and most of the methods do not strictly satisfy the definition of pure shear. In this study, a modified shear test specimen was proposed to measure the shear fracture toughness by uniaxial loading in a tensile testing machine. High density polyethylene (HDPE) was used as test material for the experiments. The specimen was created in order to suit the most common used tensile test machine. The specimen was then optimized by using finite element analysis (FEA) to find the geometry and the size of the pre-notch to avoid the mixed mode loading and minimize effects of normal stresses. For the specimen in discussion, an upper and lower limit of usable ligament length can be found. A method for determining the fracture toughness was discussed according to the essential work of fracture. Finally, an example of a special application of the proposed specimen was presented where the variation of shear strength of controlled delamination material (CDM) was measured.
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| 2. |
- Islam, Md. Shafiqul, 1984-, et al.
(författare)
-
Study of Shear Dominant Delamination in Thin Brittle-High Ductile Interface
- 2016
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Ingår i: 21ST EUROPEAN CONFERENCE ON FRACTURE, (ECF21). - : Elsevier. ; , s. 152-157
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Konferensbidrag (refereegranskat)abstract
- Thin laminates of Aluminum (Al) foil and Low Density Polyethylene (LDPE) film are essential constituents of food packages where these two substrates are bonded together with a thin layer of LDPE acting as adhesive. Noticeably, Al is a low ductile/quasi brittle material, whereas LDPE is highly ductile. The mechanism of delamination and strength of bond between the interfaces dictates the continuum and damage behavior of this composite. However, measuring the shear delamination properties is challenging as conventional test methods have limitations when the substrates are very thin and flexible. This study explains a tentative method that uses uniaxial tensile testing on the pre-cracked specimen of this composite to find energy dissipation due to shear delamination and successfully uses it in Finite Element Simulation in Abaqus. The delamination was observed in a narrow strip-like region close to fracture surfaces and measured with special visualization aid. A similar response was found in FEM simulation. Scanning Electron Microscopic (SEM) study of delaminated interface confirms the delamination to be shear in nature. In a cohesive zone modeling in Abaqus, the measured shear delamination energy was used as input parameter along with an arbitrary bi-linear cohesive law for validation of the experimental measurement.
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