变截面组合桁架臂非线性稳定性理论分析与动态仿真研究

发布时间：2018-05-02 05:38

本文选题：组合桁架臂 + 非线性　；参考：《太原科技大学》2017年硕士论文

【摘要】：港口、海工装备、第三代核电等领域模块化与大型化吊装作业的需求,促使起重机起重量趋向重载化、自重趋向轻量化、空间趋向大型化、操作趋向智能化、作业趋向复杂化、结构趋向柔性化,而精益的生产离不开高品质、高效率、高安全性能的搬运系统,优质高强钢的应用使起重机臂架结构轻质化却导致结构柔度增大,重载作用下结构几何变形具有较强的非线性性,若仍采用基于小位移假定的线弹性理论对大长细比桁架臂结构进行线性分析,将偏离结构实际受力状态,得出偏于安全或不正确的结果,切乎实际的设计理论有助于维持结构强度与稳定性之间的平衡;其次,重载起升过程中,极限大角度工况下倘若有效载荷意外丧失,因臂架弹性、重物重力、钢丝绳张力所蕴藏势能瞬间释放之故,对结构产生剧烈冲击与振动,为臂架防后倾装置以及系统安全性带来新挑战,再者,如何准确模拟反向冲击载荷,对结构所处真实环境,避免夸大或缩小结构动力响应,具有现实意义。本文选取某型起重机大长细比组合桁架臂为研究对象,基于不同方法理论设计校核臂架结构强度、刚度及稳定性(整体稳定性、局部稳定性),重点落脚于稳定性的非线性求解,通过引入广义裕度概念,评价不同方法理论体系优劣,遴选出最佳设计方法,借助ANSYS对其验证,并对仿真要点详细论述;以多柔体动力学为理论指导基础,以虚拟样机技术为解题手段,联立ANSYS与ADAMS建造臂架刚柔耦合模型,对有效载荷意外丧失工况进行理论建模和数值仿真,探讨弹性臂架在瞬态冲击激励下的振动响应,动态分析防后倾装置受力特征,此外,遵循单一控制变量原则,深入挖掘不同设计因子(有效载荷意外丧失时间、滑轮组倍率、起升加速时间)对臂架动态特性影响规律,为臂架的设计改进以及防后倾装置的选型、合理布置提供重要的理论参考依据。
[Abstract]:The demand for modularization and large-scale hoisting operations in the fields of port, marine engineering equipment, third generation nuclear power, etc., has prompted crane lifting weight to become heavy, self-weight to be lighter, space to be large, operation to be intelligent, and operation to be more complicated. The structure tends to be flexible, but lean production can not do without high quality, high efficiency, high safety performance of the handling system. The application of high quality and high strength steel makes the crane jib structure lightweight, but leads to the increase of structural flexibility. The geometric deformation of the structure under heavy load has strong nonlinearity. If the linear elastic theory based on the assumption of small displacement is still used for linear analysis of the truss arm structure with large slenderness ratio, it will deviate from the actual stress state of the structure. The result is that the actual design theory is helpful to maintain the balance between the strength and stability of the structure. Secondly, in the course of heavy load hoisting, if the payload is lost unexpectedly under the condition of extreme large angle, Because of the sudden release of the potential energy contained in the elasticity of the boom, the gravity of the heavy object and the tension of the wire rope, it has produced violent impact and vibration on the structure, which brings new challenges to the anti-tilt device of the boom and the safety of the system. How to simulate the reverse impact load accurately is of practical significance to the real environment of the structure and to avoid exaggerating or reducing the dynamic response of the structure. In this paper, a large aspect ratio composite truss arm of a certain crane is chosen as the research object. Based on different methods, the strength, stiffness and stability of the jib structure are designed and checked (global stability, local stability and nonlinear solution of stability). By introducing the concept of generalized margin, this paper evaluates the advantages and disadvantages of different methods, selects the best design method, verifies it by means of ANSYS, and discusses the main points of simulation in detail. The rigid-flexible coupling model of boom is constructed by using virtual prototyping technology and ANSYS and ADAMS, and the theoretical model and numerical simulation of the accidental loss of payload are carried out, and the vibration response of elastic boom under transient shock excitation is discussed. In addition, according to the principle of single control variable, the influence of different design factors (the time of accidental loss of payload, the ratio of pulley group, the time of hoisting acceleration) to the dynamic characteristics of boom is analyzed dynamically. It provides an important theoretical reference for the design and improvement of the boom, the selection of the anti-tilting device and the reasonable arrangement.
【学位授予单位】：太原科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH21

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