| Polymethylmethacrylate(PMMA),also known as plexiglass or acrylic glass,is a commonly used polymer due to its outstanding properties such as strength,optical performance,transparency,hardness,and weather resistance.It finds broad applications in various fields,including construction,automobile,aerospace,electronics,medical,marine,and everyday life.With the development of deep-sea exploration and scientific investigation,transparent structures like PMMA are increasingly used in deep-sea equipment such as multifunctional submersibles and launch vehicles.Consequently,the deep-sea application of PMMA structures has encountered new challenges and demands.These structures must not only meet the static strength safety requirements posed by deep-sea hydrostatic pressure but also withstand dynamic structural safety problems caused by collisions and impacts in the deep-sea environment.Therefore,it is of great scientific and engineering significance to study the impact performance of deep-sea PMMA structures in the current era of deep-sea development.This paper utilized the Johnson-Cook constitutive and damage failure model and numerical simulation technology to investigate the mechanical behavior of PMMA material structures under the impact of steel projectile penetration and other impacts in various environments.The study covered the following aspects:1、The J-C constitutive and damage failure model was employed to investigate the mechanical properties of PMMA materials.The parameters of the J-C model were determined by fitting the test data of PMMA materials with the least square method.The study elucidated the influence of temperature,stress triaxiality,and strain rate on the mechanical properties of PMMA,and the accuracy of the model was verified by comparing the results with test data;2 、 This paper developed a finite element model and a parametric numerical impact simulation analysis system for steel projectile penetrating PMMA plate using PMMA material test data and J-C constitutive and damage failure models.The study investigated the change in steel bullet velocity after impact by varying the velocity of steel bullet and PMMA plate with different thickness and size.The numerical simulation results were in good agreement with the experimental test results,validating the reasonableness of the calculation model and method presented in this paper;3、Using the impact model of PMMA material structure proposed in this paper,a parametric study was conducted to analyze the mechanical properties of PMMA structure impact.The study examined the impact of plate thickness and incident velocity of steel projectile on size and velocity.The calculated results indicated that the residual velocity of the projectile decreased as the PMMA target plate became thicker,and that the residual velocity was roughly proportional to the thickness of the target plate;4、This study uses a simplified finite element calculation model to analyze the impact of deep sea PMMA structures.The model is based on the local structure of the glass spherical shell,which is simplified to a flat plate.The load of the calculated model plate structure is determined according to the stress of the spherical shell structure under deep sea pressure.The impact performance and strength analysis of PMMA structures under different deep-sea pressures are calculated using a numerical simulation method.The findings indicate that the deeper the depth,the higher the residual velocity of the projectile,which suggests that the impact resistance of PMMA material is weakened due to deep-sea pressure.To sum up,this paper has carried out a preliminary numerical simulation study on the impact performance of the PMMA structure of the deep-sea equipment and the deep-sea pressure environment,providing some references for the further research of the PMMA deep-sea application and structure. |
