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/lp/emerald-publishing/the-amsler-high-frequency-vibrophore-TG8nPPWZuD
- Publisher
- Emerald Publishing
- Copyright
- Copyright © Emerald Group Publishing Limited
- ISSN
- 0002-2667
- DOI
- 10.1108/eb031520
- Publisher site
- See Article on Publisher Site
Abstract
The Amsler High Frequency Vibrophore An Instrument for Fatique Tests with maximum loads of 2,000 kg. and 10,000 kg. HE Amsler High Frequency Vibrophores one (±) , as a progressive one (0 to —, or 0 to + ) serve for determining the resistance to re or as one with any desired tensile or compressive peated tension or compression loads or to preload. The amplitude of the load can be re alternate tension/compression stresses of metallic gulated exactly and maintained constant, by (ferrous and non-ferrous) and non-metallic means of a special photo-electric amplitude re materials (such as ceramics, plastics, etc.) of gulating device controlled by the light-beam of the dynamometer. Thus the desired value of load suitable size and shape, as well as for investi amplitude is directly maintained constant and all gating the resistance to dynamic forces of struc tural elements and assemblies such as riveted outside influences such as variation of ampli or welded joints, threaded sections, wires for fier, frequency, etc.. are eliminated. The desired cables and concrete, etc. They also serve for load amplitude is set on the dynamometer scale the quantitative determination of the damping by means of a slide. A synchronous counter, capacity of materials. operated by the amplifier, indicates the number of oscillating loads applied to the specimen. This counter can also be used for measuring the Construction frequency. A relay stops the operation of the The machines operate on the resonance prin machine at the moment of fracture of the test ciple, the number of cycles coinciding always with piece but, as the sensitiveness of this relay is the natural frequency of the vibrating elements, a adjustable, the operator can set it at will to stop condition realized by the use of an impulse the machine either when the first crack appears generator and an electronic amplifier excited by or only after the specimen has entirely fractured. the machine itself. The magnitude of the natural frequency depends on the size and elasticity of Damping Properties of Materials the specimen and on the weight of the oscillating masses and can be changed conveniently within The damping properties of materials can be down more or less quickly according to the extent wide limits by adding or removing weight disks determined by decreasing-amplitude tests. When of mechanical hysteresis of the material under thus altering the main mass. In this way the the Vibrophore is stopped the amplitude dies test and from the rate at which the oscillations operator is not bound to adhere to one definite diminish, the internal friction of material, that GENERAL CHARACTERISTICS size of specimen. is the damping, can be determined. For this Model 2·HPF421 10 HFP 422 purpose a load/time curve is registered photo The force in action is measured by an optical Max. alternating load metric tons ±1 ±5 dynamometer. A beam of light indicates directly graphically within a drum camera (supplied on Max. unilateral tensile or compres sive load metric tons 2 10 on a scale the static as well as the kinetic (vibrat special order only). For the absolute determi Max. elongation on specimen mm. ±0·3 ±0·3 ing) loads. The latter indication appears in the nation of the damping it is necessary to deduct, Range of frequency of stress cycles cycles per second 50 to 200 50 to 300 form of a band, the extremities of which cor from the figures obtained, the natural damping of Max. damping of specimen watt 40 200 respond to the maximum loads applied. The {Concluded opposite) Power input watt 200 500 Accuracy of dynamometer from 1⅛ dynamometer is constructed in such a manner Fig. 2 (left).—General view identifying the prin up to max. capacity in per cent of that the frequency does not exercise any in the load adjusted ±1·5 ±1·5 cipal parts of the Vibrophore, 10 kg. size Load constancy at ± 10 per cent fluence on the road readings. 1. Principal weight, can 9. Dynamometer scale fluctuations of the line voltage: The calibration of the machine remains con better than 1 % 1% be varied 12. Slideforphoto-electric Max. distance between specimen stant, but can be checked at any time desired, in 2. Counter weight, i.e. cell holders mm. 260 430 heavy concrete base on 14. Driving magnet a simple manner. Free space between the columns mm. 400 400 vibration insulators 18. Specimen holder The dynamometer can easily be exchanged for Total weight without base block 3. Specimen 67, 68, 69. Arrangement one of smaller capacity—smaller load range, re about kg. 600 700 5. Pre-load spring for locking the ad- sulting in greater sensitiveness at low loads. Weight of base block about kg. 1,800 1,800 6. Pre-load adjusting screw justing screw Additional dynamometer for The load can be chosen as a true alternating metric tons ±0·2 ±1 Fig. 3 (centre).—Covers removed to show the dynamometer 48. Oscillating mirror for adjusting position of the light beam, the tube underneath is the source of light Fig. 4 (below).—Gripping head for metal strips and wires 56. Gripping block 57. Split adaptor 58. Liner fo r gripping block 60,61,62. Locking screws 206 Aircraft Engineering
Journal
Aircraft Engineering and Aerospace Technology – Emerald Publishing
Published: Jun 1, 1947