Dynamic Performance Of Reusable Viscoelastic/Elastic Energy Absorbing Materials

During the operation of the spacecraft,various vibration and impact loads are inevitable.How to design and develop new energy absorbing materials to reduce the equipment damage due to these loads has become the research focus in aerospace engineering.The lightweight porous material has excellent energy absorbing properties,and the viscoelastic material itself has excellent energy dissipation performance.How to effectively combine the advantages of these two materials to construct a reusable and space-saving material with excellent energy absorption and anti-vibration properties has important meaning in equipment design under extreme conditions.Based on the porous structure,novel elastic/viscoelastic material models are established.Using finite element simulation,the influences of pore shape,porosity,material parameter and viscoelastic dissipation rate on the energy absorption properties of viscoelastic/elastic integrated materials are discussed.The main research contents of this paper are as follows:(1)The dynamic responses of the viscoelastic/elastic energy absorbing material with different viscoelastic inclusions under the out-of-plane sinusoidal load and the in-plane half-sinusoidal impact load are investigated.The energy absorbing material model with viscoelastic inclusions is established.The dynamic responses of viscoelastic/elastic energy absorbing materials with different inclusions and volume fractions,as well as viscoelastic decay constants under different loads are studied.The sensitivity analysis about the energy absorbing on the viscoelastic material volume fraction and viscoelastic attenuation constant is performed.The influence of microstructure shape,porosity and decay constants on the acceleration and energy absorption is clarified.The results show that the main factors affecting the vibration attenuation of the materials are the volume fraction of viscoelastic material and the viscoelastic decay constant,and insensitive to the microstructure shape.(2)The dynamic responses of viscoelastic/elastic energy absorbing materials with sinusoidal periodic microstructures under impact loads are studied.The energy absorbing material model with sinusoidal periodic microstructures is established.The influence of viscoelastic instantaneous shear modulus and viscoelastic decay constants on the dynamic responses of the structures under impact loading is clarified.The results show that when the instantaneous shear modulus of viscoelastic materials is relatively small,the structure will have great acceleration response and deformation,and is not sensitive to the viscoelastic decay constant;otherwise,when the instantaneous shear modulus is large,the deformation is relatively small,and the acceleration response will not be amplified and is sensitive to the viscoelastic decay constant.Therefore,for a sinusoidal period viscoelastic/elastic energy absorbing material,a viscoelastic material with large instantaneous shear modulus and fast viscoelasticity attenuation should be selected to obtain better anti-vibration and buffering effect.