Experimental test system and method for dynamic characteristics of dry friction damping

Abstract

The invention discloses an experimental test system and method for dynamic characteristics of dry friction damping. The experimental test system comprises a moving flat plate, a fixed flat plate and a laser vibration meter, wherein a piezoelectric holding device and a motion transmitting mechanism are fixedly mounted on the movable flat plate; the piezoelectric holding device and the motion transmitting mechanism are connected through a piezoelectric actuator; the motion transmitting mechanism is fixedly provided with a first simulation piece clamp; the first simulation piece clamp is provided with a first blade root platform simulation piece. the fixed flat plate is arranged; the fixed flat plate is fixedly provided with a signal holding device; the signal holding device is provided with a piezoelectric force sensor; the piezoelectric force sensor is connected with a second simulation piece clamp through a force transmitting mechanism, and the second simulation piece clamp is provided with a second blade root platform simulation piece; and the laser vibration meter is arranged. According to the invention, experimental research and contact parameter estimation are combined, specific quantitative evaluation is carried out on the motion characteristics of a friction damper, and systematic research can be carried out on the dynamic characteristics of the dry friction damping of a gas turbine blade material.

Description

technical field [0001] The invention belongs to the technical field of dry friction damping mechanism testing of metal materials, and in particular relates to an experimental testing system and method for dynamic characteristics of dry friction damping. Background technique [0002] For gas turbine compressors and turbine blades with dry friction damping structure, the friction between the contact surfaces is the key to dissipate the vibration energy of the blades. In-depth research on the dynamic characteristics of friction damping between the contact surfaces is very important for revealing the dryness of steam turbine blades. Frictional damping vibration characteristics are very important. Due to the highly complex nonlinear characteristics of dry friction, the friction models proposed by theoretical analysis are simplified to a certain extent, and it is difficult to solve them accurately. Therefore, the experimental test is still the key to determine the dynamic characte...

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Problems solved by technology

[0003] At present, some scholars have used experimental methods to conduct preliminary research on the dynamic characteristics of frictional damping between the contact surfaces of metal materials. There are few studies on alloy steel materials

The high-temperature nickel-based alloy steel material has high specific strength, high elastic modulus, and small thermal expansion coefficient. Under the same excitation conditions, it is less likely to deform than ordinary carbon steel. The obtained friction hysteresis curve is quite different from the properties of high-temperature nickel-based alloys and cannot be directly applied. Therefore, it is necessary to design an experimental test system that can accurately generate and measure the dynamic characteristics of dry friction damping for gas turbine high-temperature nickel-based alloy materials.

On the other hand, most of the current experiments study the overall influence of the friction damper on the blade from the two aspects of vibration reduction amplitude and resonance frequency shift. This black box-like method is used to evaluate the ability of the friction damper to reduce the resonance displacement. The contact characteristic parameters are obtained on the basis of direct experimental research, so it is impossible to conduct a specific quantitative evaluation of the kinematic characteristics of the friction damper; and each experiment is only measured and studied for its own working conditions, and it is difficult to form a friction contact characteristic parameter database suitable for engineering technology , and these parameters have an important influence on the dry friction damping vibration characteristics of gas turbine blades, and further research is needed

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