Spin tests

This test is performed to verify the struetural integrity of the expander wheels and the eompressor wheels. The expander wheels should be instantaneously oversped during the meehanieal test while assembled on the shaft. Compressor wheels should be oversped during the meehanieal test or, alternatively, in a separate spin test faeility. 

T) Spin Test. The purpose of this test is to check the arming characteristics of a fuze for spin-stabilized ammunition. The equipment consists of a vertical spindle that has an adapter to accommodate the test fuze. The spindle is rotated at the desired rpm by an electric motor or air. In some procedures a stroboscope is used to observe the arming characteristics of the mechanism (p IIB-26 of Ref 39)... 

Shells (loaded with Comp B) with these liners were tested by firing from the MIS rifle. These shells which rotated at about 210rpm, penetrated at least 3 inches in armor-plate in 96% of trials and 6 inches in 40% of trials. When fired at 120rpm in a spin-test app, the average penetration in mild steel was 7.4 indies. The standard 57mm M307A1 HEAT Shell which contains a hemispherical liner cannot be relied upon to penetrate 3 inches of armor plate... 

To evaluate the effects of blade geometry and configuration, Kim [1] performed a number of microrotorcraft spin tests on a single-rotor device using a load cell to measure thrust and a laser to measure rotor speed. The motor was driven using an external power supply. Kim tested blades with varying aspect ratios, cambers (the asymmetry of an airfoil s top and bottom shape), and thicknesses, tapers, pitches, and configurations. 

Compared to failure in a tensile test, the failure of components in operation can be much more complex, however. The stress field is generally not uniaxial, which may cause an intricate crack path, and in many cases secondary damage may confuse the initial picture. Figure 12.2 shows the remnants of a turbine rotor fractured in a spin test[22,23], wherethefractmeoriginwasagainidentifiedasaflawinthe microstructure. 

Figure 12.2 Turbine rotor made of silicon nitride ruptured in a spin test, (a) Fractured rotor (the location of the fracture origin is indicated by an arrow) (b) The fracture origin [22, 23],...

Figure 23.32 Series 45 Mk 4 flywheel assembled to flex rim hub and arbor interface for spin testing in an air turbine (specific energy 100 Whkg at linear velocity of rim tip speed of 1000 ms . Source Courtesy of Flywheel Energy Systems Inc., Canada.

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