GB464082A - Improvements in and relating to apparatus for testing working materials or constructional parts - Google Patents

Abstract

464,082. Testing physical qualities of materials. SCHENCK EISENGIESSEREI U. MASCHINENFABRIK DARMSTADT GES., C. Oct. 5, 1936, No. 27026. Convention date, Oct. 23, 1935. [Class 106 (ii)] An exciting means consisting of one or more rotating unbalanced masses is mounted on the free end of a spring which resiliently connects them to the body under test, and the masses are rotated at or near a speed corresponding to the natural frequency of the whole system. In the form shown in Fig. 1, the spring a is clamped in a fixed support b and loaded by a mass c containing the unbalanced masses d. The test bar e is clamped at one end to the spring and at the other to a fixture. The spring a, bar e, and masses c, d form an oscillating system the resiliency of which is essentially determined by the spring a. In the form shown in Fig. 2, one end of the specimen g is clamped to a fixture and the other at h to the spring i to the ends of which are secured masses k, l. Instead of one spring, two each secured to the end of the bar and lying in the same line may be used. The mass k is provided with a rotating mass m having unbalanced weights. If the mass l and arm i are properly chosen, the masses k, l will oscillate in substantially the same phase, and the specimen stressed alternately in tension and compression with large forces. A spring u arranged between the clamp and a fixture may provide a static stress. Rotating masses like k may be used at each end of the spring. To avoid disturbances to the foundation, the installation may be mounted on weak springs. In this case the test body is arranged horizontally and two similar clamping devices rest on a number of vertical springs, the clamp f being connected to a large mass resiliently mounted. It is possible to dispense with the large mass and load the body similarly at each end, the phase between the oscillating means being adjusted to produce the desired stress. Static stresses may be applied by springs. Fig. 3 shows a form for a bending test, the specimen o being fixed at one end and secured at the other to a spring q carrying a mass r and rotating unbalanced mass s. Static stress is applied by a spring t. Torsional stress may be examined as in Fig. 4, which is similar to Fig. 3, except that the spring u and masses x, y have been turned through a right-angle.