Influence of temperature and strain rate on cohesive properties of a structural epoxy adhesive
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Effects of temperature and strain rate on the cohesive relation for an engineering epoxy adhesive are studied experimentally. Two parameters of the cohesive laws are given special attention: the fracture energy and the peak stress. Temperature experiments are performed in peel mode using the double cantilever beam specimen. The temperature varies from −40 to + 80°C. The temperature experiments show monotonically decreasing peak stress with increasing temperature from about 50 MPa at −40°C to about 10 MPa at + 80°C. The fracture energy is shown to be relatively insensitive to the variation in temperature. Strain rate experiments are performed in peel mode using the double cantilever beam specimen and in shear mode, using the end notch flexure specimen. The strain rates vary; for peel loading from about 10−4 to 10 s−1 and for shear loading from 10−3 to 1 s−1. In the peel mode, the fracture energy increases slightly with increasing strain rate; in shear mode, the fracture energy decreases. The peak stresses in the peel and shear mode both increase with increasing strain rate. In peel mode, only minor effects of plasticity are expected while in shear mode, the adhesive experiences large dissipation through plasticity. Rate dependent plasticity, may explain the differences in influence of strain rate on fracture energy between the peel mode and the shear mode.
KeywordsCohesive law Strain rate Temperature dependence Experimental DCB-specimen ENF-specimen Crashworthiness
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- Alfredsson KS, Biel A, Leffler K (2003) An experimental method to determine the complete stress-deformation relation for a structural adhesive layer loaded in shear. In: Proceedings of the 9th international conference on the mechanical behaviour of materials, Geneva, Switzerland, 2002Google Scholar
- Biel A (2008) Cohesive laws for adhesives at repeated loading—an experimental method (in preparation)Google Scholar
- Biel A, Carlberger T (2007) Influence of temperature on cohesive parameters for adhesives. In: Sørensen BF, Mikelsen LP, Lilholt H, Goutianos S, Abdul-Mahdi FS (eds) Procceedings of 28th Risø international symposium on materials scienceGoogle Scholar
- Kinloch AJ (1987) Adhesion and adhesives—science and technology. Chapman and Hall, LondonGoogle Scholar
- Lutz A, Schneider D (2006) Toughened epoxy adhesive composition. USPTO Applicaton #: 20060276601—Class: 525528000 (USPTO), Dow Chemical Company—Midland, MI, USAGoogle Scholar
- Salomonsson K, Stigh U (2008) An adhesive interphase element for structural analyses. Int J Numer Methods Eng (To appear). doi: 10.1002/nme.2333
- Schmidt P (2007) Computational models of adhesively bonded joints. PhD thesis, Linköping UniversityGoogle Scholar
- Stigh U, Andersson T (2000) An experimental method to determine the complete stress-elongation relation for a structural adhesive layer loaded in peel. In: Williams JG, Pavan A (eds) Fracture of polymers, composites and adhesives. ESIS publication 27.. Elsevier, Amsterdam, pp 297–306CrossRefGoogle Scholar