Non-linear dynamic parameter testing method and system of fiber composite board in thermal-shock environment

Abstract

The invention provides a non-linear dynamic parameter testing method and system of a fiber composite board in a thermal-vibration environment. The method comprises the steps that the thermal-vibrationtesting environment is built, the fiber composite board is fixed to an installation platform of a vibration module through an installation clamp, the installation platform stretches into a thermal-insulated box of a thermal environment simulation module, and then the thermal-insulated box is sealed with a soft rubber strip; a laser scanning vibration measurement module is arranged above the thermal-insulated box, and during testing, laser penetrates through high-temperature-resistant optical glass on the top surface of the thermal-insulated box to scan the fiber composite board; the non-linear inherent frequencies of various orders, the non-linear modal shapes of various orders and the non-linear damping of the fiber composite board at different excitation amplitudes in the thermal-vibration environment are tested in sequence. The testing method and system are perfect and effectively, and the non-linear dynamic parameters including the non-linear inherent frequencies, the non-linear modal shapes of various orders and the non-linear damping can be accurately obtained.

Description

technical field [0001] The invention belongs to the technical field of vibration testing, in particular to a method and system for testing nonlinear dynamic parameters of a fiber composite board in a thermal vibration environment. Background technique [0002] Fiber-reinforced composite materials and their structures have high specific strength, high specific modulus, material designability, good thermal stability, and also have the advantages of large bearing capacity and light weight. They are widely used in aviation, aerospace, automobile industry, Important fields such as ships, sports equipment and weapons industry. At present, there are a large number of composite plate structural parts made of this type of material in engineering practice, and they are usually in a thermal vibration environment of hundreds of degrees Celsius or even thousands of degrees Celsius, such as hypersonic aircraft, aeroengines and gas turbine blades. The combined effect of thermal load and d...

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Problems solved by technology

At the same time, its macroscopic structure also exhibits damping characteristics that vary with the amplitude and frequency of the external excitation (called frequency dependence and amplitude dependence) and nonlinear stiffness characteristics (the natural frequency also changes with the amplitude), which gives The traditional linear equivalent-based dynamic analysis and test methods pose great challenges. So far, the academic and engineering circles have not established a complete method for testing the nonlinear dynamic parameters of fiber composite panels in thermal shock environments. However, there is a lack of a dedicated test system to accurately obtain nonlinear dynamic parameters including nonlinear natural frequency, nonlinear mode shape and nonlinear damping for effective testing methods.

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