| The refrigeration system provides basic guarantee for the normal work of personnel or material storage in the process of ship navigation,in which the refrigerant plays the key role in determining the system performance,in a complex impact environment,however,it is difficult to avoid the leakage of refrigerant.This will eventually affect the normal work of the ship and need immediate supplement.In this thesis,the dynamic design analysis method(i.e.,dynamic design analysis method: DDAM)and dynamic time domain simulation are used to study the R404 A refrigerant storage tank designed according to the pressure vessel standard,to investigate the maximum stress response and determine whether its strength meets the requirements.On the basis of the original design model parameters,the multi-objective genetic algorithm optimization is carried out to reduce the production cost and verify the reliability of the structure.Finally,make an EDS component analysis for the weak areas of the specified process simulation.The main research work of this thesis is as follows:(1)Based on the theoretical design of R404 A refrigerant storage tank,the natural pressurization of refrigerant in the storage tank due to heat absorption is calculated with the saturated homogeneous model under the given initial pressure.Through the analysis of natural pressurization in the tank with time,it provides a theoretical basis for the follow-up simulation.(2)The finite element analysis model of the tank is established according to the self-designed tank.After determining the element type and material properties of the finite element model,the boundary conditions are set.Through the establishment of high-quality mesh model,the reasonable numerical simulation method is determined according to the research object.On this basis,the mesh independence test is carried out to determine the reasonable number of meshes.(3)Based on the finite element analysis model of R404 A refrigerant storage tank,according to GJB 1060.1-91 The frequency domain analysis of the impact resistance performance of the refrigerant storage tank is carried out by using the dynamic analysis method in the thesis: on the premise that the comprehensive modal mass is greater than 80%of the total mass of the equipment,the main modes in all directions are extracted,and the impact input spectrum is generated according to the relevant specifications to load and calculate the impact response of the refrigerant storage tank.(4)According to the empirical formula in BV043 / 85,the shock load spectrum is transformed into the shock signal in the form of double triangular wave as the input environment: the transient dynamic analysis of the finite element model in a short time is carried out,and the nonlinear response process of the model is studied under the arbitrary changing load with time by taking the input data as the load of time function.(5)The multi-objective genetic algorithm(MOGA)is mainly used to reduce the production cost of R404 A refrigerant storage tank,that is,to reduce the amount of manufacturing materials as much as possible,and to ensure the impact resistance of the product during the structural optimization design,that is,to ensure that the maximum impact response stress of the product is maintained below a set value and will not rise again.(6)According to the specified welding process,on the premise that the welding process is controllable,TC4 parts with 0.8 mm thickness and TA1 titanium welding wire with 0.8mm diameter are welded,and the materials in the weld area are cut to make 5 mm thick × 5mm sample size.After that,the SU-8010 scanning electron microscope produced by Hitachi company in Japan was used for EDs spectrum analysis,and relevant suggestions were put forward according to the analysis and detection results,so as to enhance the impact strength of the weld. |
