| A large number of earthquake damage surveys of buildings indicate that collisions are one of the important reasons for the collapse and damage of civil engineering structures.The same is true for spillway gate structures in water conservancy projects.In order to provide sufficient bearing capacity,some spillway structures will be equipped with a double-column machine.The special structural properties of the double-column machine bridge structure provide favorable conditions for collisions between structures.When subjected to strong earthquakes,collisions between adjacent machine bridge structures are extremely easy to cause the collapse and destruction of the structure.Therefore,analyzing the collision mechanism of machine bridges under earthquake action and exploring active and effective optimization methods have important practical significance for the seismic design of machine bridges.This subject uses ANSYS/LS-DYNA to numerically simulate the structure of the double-column spillway machine bridge to study the basic dynamic characteristics of this structure and the mechanism of collision damage under the action of an earthquake.At the same time,an optimization measure that can reduce the collision response is proposed and its optimization effect is verified.The main research contents of this topic are as follows:1.This topic introduces common collision analysis methods,and studies the analysis modes and scope of application of the contact element method and the coefficient of restitution method,which are widely used in structural collision research,and briefly introduces the explicit finite element software ANSYS/ LS-DYNA.2.Based on ANSYS/LS-DYNA software,the basic dynamic performance of the machine bridge structure and the collision response law under earthquake action are obtained through dynamic time history analysis and collision characteristic analysis.The research results show that the collision effect can change the motion period and frequency of adjacent structures.Under certain conditions,it can make the structure produce relatively large relative displacement.At the same time,the collision effect makes the structure acceleration appear pulse phenomenon.The node acceleration peak at the collision contact position is 15 times the acceleration peak value without considering the collision effect.This shows that the collision effect can have an extremely serious impact on the safety and stability of the structure.It can even affect the normal use of the structure under special conditions.3.Fill the expansion joints of the frame bridge with damping and energy-consuming materials to optimize the machine bridge structure and perform seismic collision response analysis again,and then compare the response results with the response results without measures to verify the optimization of the method effect.The research results show that the anti-collision measure does not completely prevent the collision phenomenon of the machine bridge structure,but it has a significant inhibitory effect on the displacement response,velocity response,acceleration response,and stress response of the structure.This measure makes the structure’s displacement response,velocity response,acceleration response,and stress response within the safety range specified by the code. |
