Research On The Shock Assessment Of Large Shipborne Equipment And System And The Floating Shock Platform Experiment

Good shock resistance of shipborne equipment is very important to improve the survivability of warship.There is still a certain gap between China and Western naval powers in assessment specifications and facilities construction of large and medium-sized shipboard equipment.The United States has mature military standards such as MIL-S-901)modified and perfected in the equipment shock assessment specifications,and light,medium and large floating shock platforms used in conjunction with the standards are used as assessment tools for shipborne equipment.Comparatively,the reliability and operability of assessment specifications for large and medium-sized shipboard equipment in China are insufficient.In recent years,small,standard,medium and large floating shock platform have been gradually developed,but they are still in the preliminary stage of research and have many problems.Under this background,this paper carries out experimental research on dynamic characteristics of floating shock platform,reveals the mechanism of assessment equipment of floating shock platform,calibrates the capability of assessment equipment of floating shock platform,evaluates the validity of numerical calculation method of floating shock platform,and evaluates the impact resistance of shipboard equipment,providing reference for shock assessment of shipboard equipment in China.Based on the research background and practical engineering significance,this paper starts from the research on shock resistance of shipboard equipment,introduces the theory and test method of shock resistance of shipboard equipment,summarizes the research status of shock resistance of shipboard equipment at home and abroad,and summarizes the related research progress.The treatment methods of shock acceleration signal and pressure signal in test method are emphatically introduced,which lays a foundation for the following research work.Aiming at the assessment of shock resistance of a diesel generator set,the corresponding mechanical model is established based on the multi-rigid body dynamic discrete time transfer matrix method,the forms of transfer matrices of different components are derived,the input load form of the model is defined according to the requirements of impact assessment for shipboard equipment in the military standard,and the shock response under the condition of non-linear characteristics of vibration damper elements is studied.The shock assessment of large and medium-sized shipboard equipment is usually simplified as a rigid body model,but the pipeline system has obvious elastic characteristics.The transfer matrix of elastomer is given based on the discrete time transfer matrix method and the solution method of element transfer equation is obtained by referring to the precise integration method.Considering the space complexity of pipeline system,an automatic generation method of pipeline system overall transfer matrix based on topological structure is proposed.The offshore test on floating shock platform is carried out,and the basic conditions of the test,such as operating condition setting,ballast setting and arrangement of various measuring points are briefly introduced.Aiming at the problems existing in the acceleration measurement results,a signal processing method suitable for underwater explosion shock response acceleration is proposed,such as signal truncation,filtering,eliminating trend terms,rigid body motion correction,etc.The shock response spectrum analysis of the processed acceleration signal is carried out,and the shock resistance of the floating shock platform to the shipboard equipment is obtained.Considering the complexity of offshore test environment,the blasting source location technology based on shock wave zero-time method is optimized.In the field of ship shock resistance,the shock response spectrum of structure under explosive load is generally used to measure the shock strength.According to the characteristics of shock response spectrum in different frequency bands,it can be rounded into shock design spectrum,which can be used as the design standard of equipment against shock.However,there are a lot of approximate processes and uncertainties in the roundness of shock response spectrum,and the spectrum of the same plate frame differ greatly in different space locations.These phenomena reflect that there are a lot of non-linear characteristics in the shock response of structures under underwater explosion.In this paper,based on the surrogate data method and a series of methods for estimating characteristic quantities in nonlinear dynamics,the measured shock signals are analyzed nonlinearly,the characteristics of various alternative data generation methods are analyzed,and the estimation methods for some characteristic quantities are optimized.The non-linear characteristics of structure shock response signal under underwater explosion are studied.It is considered to be a more accurate and direct method to study the shock resistance of shipboard equipment by test method,but the numerical calculation method also plays an important role because it is difficult to carry out explosive shock test in real scale and scale model.The important problem of using numerical calculation method is how to evaluate the validity of its model.In this paper,the method of confirmation measurement is used to carry out quantitative analysis of numerical calculation results and test results,and qualitative analysis is carried out in the form of subject matter expert scores,and the mapping relationship between quantitative and qualitative analysis results is established by means of probabilistic neural network.The overall effectiveness evaluation results of the model are given.