CompositesWorld
Issue link: https://cw.epubxp.com/i/576646
18 CompositesWorld DESIGN & TESTING OCTOBER 2015 ABOUT THE AUTHOR Dr. Daniel O. Adams is a professor of mechanical engineering and has been the director for 18 years of the Composite Mechanics Laboratory at the University of Utah and vice president of Wyoming Test Fixtures Inc. (Salt Lake City, UT, US). He holds a BS in mechanical engineering and an MS and Ph.D in engineering mechanics. Adams has a combined 35 years of academic/ industry experience in the composite materials feld. He has published more than 120 technical papers, presents seminars and chairs both the Research and Mechanics Divisions of ASTM Committee D30 on Composite Materials and the Testing Committee of the Composite Materials Handbook (CMH-17). He regularly provides testing seminars and consulting services to the composites industry. REFERENCES 1 D. E. Walrath and D. F. Adams, "The Iosipescu Shear Test As Applied to Composite Materials," Experimental Mechanics, Vol. 23, No. 1, 1983, pp. 105-110. 2 ASTM D 5379/D 537M-12, "Standard Test Method for Shear Properties of Composite Materials by the V-Notched Beam Method," ASTM International (W. Conshohocken, PA, US), 2012 (frst issued in 1993). 3 ASTM D 7078/D 7078M-12, "Standard Test Method for Shear Properties of Composite Materials by the V-Notched Rail Shear Method," ASTM International (W. Conshohocken, PA, US), 2012 (frst issued in 2005). 4 "Plane-Shear Measurement with Strain Gages," Vishay Precision Group Tech Note TN-512-1, Document No. 11062, September 2010, www.vishaypg.com/docs/11062/tn5121tn.pdf 5 D.O. Adams, J.M. Moriarty, A.M. Gallegos, and D.F. Adams, "The V-Notched Rail Shear Test," Journal of Composite Materials, Vol. 41, No. 3, 2007, pp. 281-297. 6 D.J. Litz, "Development of the Combined Loading Shear Test Method and Shear Strain Measurement in the V-Notched Rail Shear Test," MS Thesis, Department of Mechanical Engineering, University of Utah, 2012. cases, the combined loading shear test fxture provides even higher shear load capacity. Shown in Fig. 1c (p. 14), this method combines the edge-loading method of the Iosipescu test and the face-loading method of the V-notched rail shear test. Although the central V-notched region of the specimen is the same as the V-notched rail shear specimen, the gripping region on either end is elongated by 25 mm to provide twice the length for edge and face loading. Te resulting 127-mm long by 56-mm wide specimen has been shown to produce acceptable gage-section failures of relatively thick lami- nates that require failure loads above 100 kN 6 . Note that the fxture body is much heavier and contains larger-diameter bolts on each side, compared to the V-notched rail shear test fxture. In summary, the choice of V-notched shear test method is best made with the composite to be tested frmly in mind. To obtain the in-plane or interlaminar shear properties of composite materials, all three test methods can be used. However, the Iosipescu shear test, which uses a smaller specimen and a smaller, less expensive fxture, is the preferred method for most users. Te V-notched rail shear test provides a signifcantly larger test section required for testing relatively coarse woven or braided textile compos- ites, as well as an increased loading capacity to enable the testing of multidirectional composite laminates. Finally, the combined loading shear test ofers the greatest shear load capacity, permit- ting the shear testing of relatively thick specimens from high- shear-strength laminates used in structural applications. diabgroup.com Making your products stronger, lighter and more competitive Experience a core commitment that stands fi rm Wind | Marine | Transportation | Industry | Aerospace | Construction | Subsea |