Research On Synergistic Deformation Of Combined Structure Of Membrane Radome

The membrane-type radome is a kind of composite structure of membrane and steel frame,which has the advantages of good wave permeability,large span and light weight and can meet the protection requirements of large-scale radar system on ship.The systematic research on this kind of composite structure is of great significance to the development of new military radar system.In this paper,the non-linear mechanical properties of the membrane(PTFE)and the cooperative deformation of the composite structure of the membrane and the support frame were studied for the design requirements of the membrane-type radome.The main contents are as follows:(1)The non-linear mechanical properties of the membrane were studied by experiments.The tensile strength and elongation at break at different loading rates were determined.The effects of factors such as loading rate,off-axis angle,and number of cycles on the ratcheting strain and residual strain of the membrane were analyzed.The data of the cyclic loading and unloading were fitted with the least square method and the average elastic modulus in the load-unload curve were obtained.The relationship with the elastic modulus loading rate,off-axis angle and number of cycles was also analyzed.The biaxial tensile tests were carried out to determine the biaxial tensile strength and the average elastic modulus in longitude and latitude direction.(2)A set of hybrid simulation test system based on PCS8000 controller and MATLAB numerical algorithm is established.The communication interface program PMI-S for static test is written in C++,and the data transfer between the numerical substructure and the test sub-structure was realized.This system lays the foundation for the study of the cooperative deformation of the composite structure of membrane and frame by using hybrid simulation methods(3)The phenomenological constitutive model of PTFE membrane material was established.A compute program was developed with MATLAB and the cooperative deformation was obtained with this program.(4)The hybrid simulation was carried out for the membrane-frame composite structure.The steel frame was divided as the numerical sub-structure and the membrane was divided as the test sub-structure.The relationship between the strain and stress during the tension of the membrane was obtained.The results from hybrid simulation were compared with those from the numerical computation to verify the rationality of the hybrid simulation method.(5)The formulas for calculating the deflection of the membrane and and the frame under the vertical load were derived based on the large deformation theory.The condition of force balance at the connection point between the membrane and the frame was established and the programe based on the MATLAB was developed to calculate the maximum deformation on the frame and the membrane.