Simplified Analysis Method On Elastic-plastic Dynamic Responses Of Hull Local Panels

Navy is the very important force to protect marine energy and defend the sovereignty.With the development of science and technology,the size of the warship is becoming bigger and bigger,and the interior structure is more and more complex.For this kind of complex structure,there will be very difficult to calculate its dynamic response.So how to calculate the dynamic response quickly is a very important question.When using the cabin to simulate the whole vessel's dynamic response,both the experiment and the finite element analysis used the clamped support or free boundary.But the study of cabin boundary is not many,so in this paper,regard the cabin to simulate the whole vessel's grillage plastic dynamic response in the non-contact underwater explosion as the engineering background,come up with cabin-beam mixed finite element method by the principle of equivalent inertia theory;and put forward on boundary concentrated mass stiffness by using the static condensation method;in the end,a method of solving grillage plastic dynamic responses using substructure method is applied,which can save time and improve the calculation speed,the main work is as follow:First of all,using the plane section assumption and the principle of equivalent inertia theory,the minor research cabin will be turned to one-dimensional hull girder,than coupling with the target three-dimensional finite element cabin element,the cabin-beam mixed finite element model has been created,using this model to solve relative plastic strain and plastic displacement,and compare the result with the model of vessel's result;The static condensation method realize that when using the freedom condensation method,the subordinate degree of freedom could be regard as the form of quality matrix and stiffness matrix coupling with the main degree of freedom.Based on the above theory,put the minor cabin into the concentrated mass and concentrated stiffness on the target cabin.And this model to solve relative plastic strain and plastic displacement,and compare the result with the model of vessel's result;The calculation model for vessel is divided into three substructures,based on fixed interface modal synthesis method,using the mode truncation criteria can cut on both sides of the substructure of freedom;and using the TL method as calculation tool.Established the double-bottom model and through the finite element calculation to prove the above theory's effectiveness.Finally,a theoretical analysis model has been created by the Virtual Constraint Boundary Modal Method.And the effective mass of the virtual constraint interface modal to polycondensation the internal degrees of the connections of the side of target cabin.Establish local vessel structural dynamics equation,the solution of the dynamic response of vessel grillage will be compared with finite element method,to prove its effectiveness.