文档介绍：I 华中科技大学硕士学位论文摘要我国造桥机工艺开发起步较晚,还没有统一的规范和技术标准可遵循。造桥机的工作环境通常比较恶劣,经常受到各种冲击载荷作用,其整体抗冲击性能日益得到工程界的关注。起重天车在导梁上停车、启动和起吊重物等工况是造桥机受到的几种主要冲击载荷,因此,有必要研究在导梁上行走的起重天车以不同速度刹车, 以及以不同速度起吊重物时,导梁由于受到起重天车冲击而产生的动态响应,以便为架桥机的抗冲击性能设计以及安全操作提供理论和技术支撑。本文运用三维动态显式有限元分析软件 LS-DYNA , 对某实际造桥机和天车动力耦合系统进行了三维有限元建模、计算和分析。在建模的过程中,为了能够模拟起重天车车轮与导轨之间的相互摩擦及起重天车在导梁上的行走,将导轨用三维实体建模,并将导轨与小车车轮之间按面- 面接触处理。在计算过程中,重点研究了天车急停减速度、天车起吊重物加速度等冲击载荷对架桥机和天车耦合系统的动力影响。动力计算表明: ( 1)天车急停减速度对造桥机内的动应力大小及其分布有重要影响。天车在导梁上以 3 m/s 的正常速度行驶中突然急停时,如果急停减速度大于 15 m/s 2 , 导梁上的最大应力会超出材料的许用应力值; 在导梁与主梁焊接处,应力最大值出现在导梁弦杆的内侧。( 2)天车起吊重物加速度对造桥机内的变形大小及其分布有重要影响。当天车分别在 s 内与 s 内将重物起吊起来时,前者使得导梁上的产生最大变形量比后者多了 % ,达到了 mm ;最大动应力均低于 210 MPa , 在安全范围内。关键词: 造桥机; LS-DYNA; 导梁; 起重天车; 冲击 II 华中科技大学硕士学位论文 Abstract Because the lag of the technical developm ent for MSS in our country,there are no uniform criterion and technic standard to follow. The MSS usually works in a poor environment and is always subjected to various impact load, so its capability of counter-impact is getting more and more a ttention by the engineering sector. There are some main impact load to MSS when the crab crane brakes, starts, or lifts models on the nose girder. It is necessary to carry on an i nvestigation in the dynamic response of the nose girder when the crab crane brakes or lifts mode ls in different velocity, so as to supply the theoretical and technical support for the count er-impact design and safe operation of MSS. This dissertation bases on 3D dynamic e xplicit CAE code LS-DYNA. The dynamic coupling psed of the crab crane a nd nose girder is three-dimensional modelled, computed and analysed. In order to simulate the mutual friction between wheels and rail and make the crab crane moves on the MSS, the rail is three-dimensional modelled with entity and the mutual friction is dealt with surface to surface contact. The dynamic coupling system’s dynamic response which is caused by the acceleration of braking and rising has been focuse