Axial compression/tension tests

The lamina s transverse compressive/tensile properties are determined from a hoop wound (90°) cylinder loaded in axial compression and/or tension. The test methods have been standardized under ASTM D5450 and D5449. The tube geometry and manufacturing procedures are similar to those used in the lamina s in-plane shear tests. 

It is convenient to consider axially loaded joints first. Furthermore, as only minimal testing of such joints in compression has been reported (see Erki, 1995), consideration will be restricted to tension testing of such joints. 

A cylindrical 70Cu-30Zn brass bar (Figure 8.20) is subjected to axial tension-compression stress testing with reversed-cycling. If the load amplitude is 10,000 N, compute the minimum allowable bar diameter to ensure that fatigue failure will not occur at 10 cycles. Assume a factor of safety of 2.5, data in Figure 8.20 were taken for reversed axial tension-compression tests, and that S is stress amplitude. 

Mechanical Property Testing. Mechanical tests were performed on both unirradiated and irradiated materials at -157°C, 24°C, and 121°C. Specimens were kept dry prior to testing in an environmental chamber mounted in a tensile testing machine. Tensile test specimens of [0]4, [10]4, [45]4, and [90]4 laminates were cut from 4-ply composite panels. All specimens were straight-sided coupons. For tension and shear tests the length/width aspect ratio was 8. For the compression tests the aspect ratio was 0.25 and the unsupported length was 0.64 cm. The [0]4 laminates were used to measure the ultimate tension and compression strength, Xit the axial... 

The standardised pin bearing test methods specify the test fixture geometry, material specimen, pin and hole dimensions and their tolerances as well as details of the test procedure. Bearing compression failure is induced at the pin-hole contact interface within the composite material specimen by means of axial tension applied to the rig and specimen. A schematic diagram of the test set-up and test specimen is shown in Fig. 13.24(a). 

Figure 8.48 Sonntag axial fatigue for DuPont Engineering Plastics Zytel 101 with alternate tension and compression 1800 cycles/min. Tests at 23°C (longitudinal orientation of the test bars) [18],...

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