Analysis And Design Of Mechanical Properties Of Elastic Elements Of Thermal Seal Structure

In the process of re-entry of hypersonic vehicle through the atmosphere,there will be high-speed airflow at the gap,which will generate aerodynamic heating phenomenon.Therefore,it is necessary to seal the thermal protection at the special gap of the fuselage.In the field of dynamic seal research,the GRC research center of NASA in the United States started earlier,and the domestic research in this field started later.In recent years,dynamic seal structure has become a research hotspot,and has made some research results.However,the research on the resilience of dynamic seal structure is mainly focused on the summary of the laws of test and numerical simulation,and the theoretical model for calculating the resilience of elastic components has not been put forward.In order to meet the requirement of predicting the mechanical properties of the dynamic seal structure in engineering practice,this paper studies the common elastic elements in the dynamic seal structure of spacecraft.By simplifying the model and adopting the equivalent principle,the theoretical model of the elastic element’s compressive resilience is established.According to the key parameters in the preliminary theoretical model,different finite element models are established by using the control variable method,and the compression simulation is carried out.The simulation results are used to verify the qualitative law of the theoretical model and correct the unreasonable part in the theoretical model due to the simplification of the model,so the theoretical model with small error is obtained.The quantitative relationship between the resilience of elastic elements and the key parameters can be obtained from the modified theoretical model.The problem of predicting the resilience of the elastic element is solved.Through t he theoretical model,it can accurately predict the resilience of different structural parameter types of elastic components and the specific structural parameter values of elastic components with specific resilience requirements.In this paper,through repeated compression tests of elastic elements under different working conditions,the law of resilience of elastic elements under repeated use is obtained.The results show that the spring resilience attenuation rate is closely related to the wire diameter.Under 1/3 compression of 0.15 mm wire diameter spring,the change rate of resilience after 7 repeated loads is only 0.6%,while under the same loading condition,the wire diameter is 0.20 mm The spring resilience decay rate is 8.67%;the spring resilience decay rate is greatly affected by the amount of compression.Under 7 times of repeated compression,the resilience decay rate of 1/3 compression amount of 0.18 mm wire diameter spring is 1.51,while under 1/2 compression amount,the resilience decay rate is 14.48%;the resilience decay rate gradually increases with the increase of compression times,5 times and 7 times of 0.20 mm wire diameter spring under 1/2 compression amount The springback attenuation rate of composite loading is 15.95% and 18.21% respect ively.