Rail shear test

J. M. itney, D. L. Stansbarger, and H. B. Howell, Analysis of the Rail Shear Test - Applications and Limitations, Journal of Composite Materials, January 1971, pp. 24-34. 

Apart from the short beam shear test, which measures the interlaminar shear properties, many different specimen geometry and loading configurations are available in the literature for the translaminar or in-plane strength measurements. These include the losipescu shear test, the 45°]5 tensile test, the [10°] off-axis tensile test, the rail-shear tests, the cross-beam sandwich test and the thin-walled tube torsion test. Since the state of shear stress in the test areas of the specimens is seldom pure or uniform in most of these techniques, the results obtained are likely to be inconsistent. In addition to the above shear tests, the transverse tension test is another simple popular method to assess the bond quality of bulk composites. Some of these methods are more widely used than others due to their simplicity in specimen preparation and data reduction methodology. 

Fig. 3.24. Schematic drawings of loading fixtures in (a) two rail shear and (b) three rail shear test. After...

Garcia, R., Weisshaar, T.A. and McWithey, R.R. (1980). An experimental and analytical investigation of the rail shear test method as applied to composite materials. Exper. Mech. 20, 273-279. 

Whitney, J.M. Stansbarger, D.L. and Howell, H.B. (1971). Analysis of the rail shear test-applications and limitations. J. Composite Mater. 5, 24-34. 

A range of shear tests exists to satisfy all the requirements for in-plane and some throughthickness shear properties. Although torsion of tubes or rods is often recommended, it is rarely used in practice and has not been standardized. Equally, the rail shear test only appears as an ASTM guide [ASTM D 4255], It is not favored, since a large specimen is required and the test suffers from premature failure initiated at the bolt holes. Several other methods that have been standardized are discus.sed below. 

Specimen configuration for the crack rail shear test is identical to the ASTM D4255 standard [15.5] specimen for the two-rail shear test. Analytical expressions for strain energy release rate determination are derived by a strength of materials approach [1.54]. 

A more practical method is to use the two-rail or three-rail shear test (ASTM D 4255) (Figures 17.46 and 17.47), although Lockwood has questioned the reproducibility [65] of the test. The ASTM is not strictly a standard, but is referred to as a guide. 

Figure 17.46 Two-rail shear test, Source Reprinted from Course on Mechanical Testing of Advanced Fibre Composites, University of London, Imperial College, Sep 1995.

The two-rail shear test is only suitable for the determination of shear moduli. The three-rail shear does give a better approximation to pure shear as the compressive load is applied parallel to the clamped edges of the specimen. 

Lockwood PA, Results of the ASTM Round Robin on the rail shear test for composites, Composites Technol Rev, 3, 83, 1981. 

A number of workers have published results on cfrp using the losipescu test [55], 4- point shear test [56], effect of specimen size [57], effect of strain rate [58], in-plane shear test [59], shear strength of pultruded product [60], rail shear test [61] and torsion test [62,63],... 

Shear 45 tension test, 10° off-axis test, rail shear test, V-notched beam test, plane-twist test, and torsion of thin-walled sample... 

ASTM D 4255/D 4255M-01 (2(X)7), Standard test method for in-plane shear properties of polymer matrix composite materials by the rail shear method, ASTM, West Conshohocken, PA. 

Under atmospheric conditions a steel specimen in a shear test will fail at a strain of about 0.5 to 1.0, however as a result of the high hydrostatic compression, the surface material of the rail accumulates an order of magnitude larger strain without failing. The compressive hydrostatic stress... 

Modified rail test See Torque strength Disk shear in compression Bond strength in compressive shear... 

ASTM D4027-98 Standard practice for measuring shear properties of structural adhesives by the modified-rail test. 

Measuring Shear Properties of Structural Adhesives by the Modified-Rail Test, Practice for (D 4027) ... 

Measuring Sttength and Shear Modulus of Nonrigid Adhesives by the Thick Adherend Tensile Lap Specimen, Practice for (D 3983) Measuring Shear Properties of Structural Adhesives by the Modified-Rail Test, Practice for (D 4027)... 

During acoustic testing at a major transit authority s elevated structure it came out that the softer the compression and shear stiffnesses of the direct-fixation elastomeric rail fastener, the better the acoustic performance. Figure 5-73 shows the noise-level reduction available from using soft elastomeric rail fasteners instead of stiff ones. The soft fastener has approximately 50 percent of the stiff fastener s spring rate. This figure shows the average wayside noise levels at 30 m (100 ft.) from an elevated structure for train operation on soft fasteners compared to stiff ones. 

Test methods see text see text rail ASTM -D790 ASTM - D953 shear ... 

Another fundamental mechanics solution that has many applications in bonded joints is that of a beam on an elastic foundation. Emil Winkler first reported this analysis in 1867 [49]. The method has been widely applied to a variety of problems, perhaps most obviously that of trains passing over rails supported by the earth, and has been included in most texts on advanced mechanics of materials [16]. Since many bonded Joints have beam-like adherends supported by a more flexible adhesive layer, this model of a beam on an elastic foundation is also of great importance for a variety of joints ranging from the lap shear specimen to fracture specimens, from peel specimens to the loop tack test. 

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