Research On Crashworthiness Of Unmanned Boat Made From Composite

With the rapid development of modern science and technology,marine intelligent transportation has become an important part of the science and technology strategies of countries around the world.As an important part of future intelligent marine transportation,composite unmanned boats are widely used to perform various military or non-war military tasks such as counter-terrorism,peacekeeping,environmental monitoring,scientific research and exploration,and search and rescue security.The probability of collision during the mission is very high,and because the composite unmanned boat is small and the overall structural stiffness is weak,the consequences are very serious once a collision event occurs.The problem of ship collision is a complex and comprehensive subject that involves multiple aspects and disciplines.In recent years,domestic and foreign countries have paid more and more attention to the problem of collision resistance of ships,and a lot of research has been done on it,but most of them are aimed at steel ships,and less research has been done on composite ships.Therefore,the research on the crashworthiness of composite unmanned boats is of great significance.This article first briefly reviews and summarizes the current status of domestic and foreign research on ship collisions and composites for ships;systematically illustrates the nonlinear finite element theory and key technologies involved in numerical simulation of ship collisions;The macro mechanics of the laminate theory is briefly explained.Based on this,the composite materials studied this time include tensile tests,compression tests,and in-plane shear tests.The basic mechanical properties of the composite materials are obtained.Provided data support for the follow-up research;taking a composite unmanned boat as the research object,combined with the transient nonlinear finite element software MSC.Dytran,impacting the impact boat laterally at different impact speeds on the composite unmanned boat and the steel unmanned boat The simulation of the dynamic process of a manned boat is carried out,with a focus on the comparative study of the collision damage forms and damage characteristics of the composite unmanned boat and the steel unmanned boat hull structure.The composite material was affected by the crashworthiness of the crashed unmanned boat,and a compound with better crashworthiness was obtained.Composite material was hit by unmanned boat pavement scheme.The effects of different side schemes on the crashworthiness of the composite material being hit by a ship are studied,and a composite side structure structure with better crashworthiness is obtained,which provides a reference for subsequent research.The main research work of this paper is as follows:(1)Research on collision nonlinear finite element theory and key technologies.The nonlinear finite element theory and key technologies involved in the numerical simulation of ship collision are systematically explained.The three simulation calculation methods for ship collision and their applicable occasions are briefly introduced;The explicit finite element solution method and the nonlinear finite element control equation are briefly described.The explicit integration time step control method is introduced,and the The constitutive model and failure criterion of materials in the collision response process briefly explain the contact algorithm and friction problems during the collision process;(2)Experimental research on the basic theory and mechanical properties of composite materials.Macro-mechanical studies of composite materials including single-layer plate strength theory and classical laminate theory are carried out on composite materials;The mechanical properties of the composite materials in this study,including tensile tests,compression tests,and in-plane shear tests,were obtained.The mechanical properties of the composite materials required for the study were obtained,which provided data support for subsequent research;(3)Based on the research of ship collision and related theory of composite materials,a composite material unmanned boat is taken as the research object,combined with the transient nonlinear finite element software MSC.Dytran,the composite boat is impacted sideways at different impact speeds on the impact boat And the numerical simulation of the dynamic process of the steel unmanned boat,focusing on the comparative study of the collision damage form and damage characteristics of the composite material hit the unmanned boat and the steel unmanned boat hull structure,and obtained the composite under different impact speed The dynamic response characteristics of the material crashed unmanned boat and the steel crashed unmanned boat;(4)The effects of different composite layup schemes on the crashworthiness of composite unmanned boats are compared and studied.Through a comparative study of the motion characteristics,acceleration,collision force and energy absorption of the main structure of the composite unmanned boat under different composite material layup schemes,a composite material layup scheme with better crashworthiness performance was obtained;The influence of different side structure schemes on the crashworthiness of composite unmanned craft.Through a comparative study of the motion characteristics of the composite unmanned boat,the stress distribution characteristics of the collision area,the acceleration,the collision force,and the energy absorption under different sideboard schemes,a composite sideboard with better collision resistance was obtained structure type.