Development For Parametric Finite Element Model And Structual Analysis Of Upper Structure Of LT53 Fire Truck

The ladder fire truck is a lifting type fire truck which equipped with telescopic ladder frames,turntables,brackets,luffing cylinders,working platforms,and safety devices on the basis of the automobile chassis.The Ladder Fire Truck Ladder System consists of a multi-section telescoping U-type truss-type ladder frame.The ladder frame structure is welded from thin-walled steels of different wall thickness and has a very complex structure.It is difficult to obtain accurate stress analysis results using traditional theoretical model.Therefore,the finite element method was used in this paper to simulate the upper structure of the ladder fire truck.This article takes upper structure of the LT53 fire truck as the research object,The parametric finite element model of the turntable,brackets,ladders,luffing cylinders and working platforms was established using the internal APDL language of commercial ANSYS software.The static analysis for upper structure of LT53 fire truck was carried out under typical working conditions.The analytical model of the ladder is deduced to obtain the theoretical solution of the tension of the ladder telescopic rope,the force of each hinge point,and the thrust of the hydraulic cylinder,contrasted it with the result of finite element analysis,and the correctness of the developing parametric finite element model is verified.Stress test experiments are performed under the typical working conditions of the ladder fire truck,and the test results are in good agreement with the finite element prediction results,which further validates the correctness of the developed finite element model.Applicated the developed finite element model to analyze the upper structure under all condition.Stress analysis results show that the fire truck structure meets strength design requirements.Displacement analysis results show that the structure meets the stiffness design requirements.The first six order natural frequency and modal vibration mode are obtained by vibration modal analysis.Based on Visual Basic,the parametric finite element analysis auxiliary software for fire trucks was developed.The software includes parametric modeling,static structural analysis,modal analysis,multi-state batch processing and automatic results report generation,Provides a calculation and analysis tool for the rational design of a series of fire trucks.