汽车起重机伸缩臂滑块对局部应力的影响分析

Analysis of the influence of the sliding block of telescopic boo m in truck crane on local stress

伸缩臂是汽车起重机的重要部件,可通过变幅、伸缩和回转运动实现搬运货物的功能,故其结构决定起重机的起重性能。各节伸缩臂间传递载荷主要通过臂节和滑块的接触作用,伸缩臂与滑块接触区域的受力情况复杂,且接触区域的应力会显著高于其他部位,故该区域对臂架整体的承载能力有较大的影响。文中研究了有限元接触理论,借助有限元软件Ansys建立臂节与滑块有限元模型,以面面接触的方式模拟臂节与滑块的接触关系,并选择多个典型工况对伸缩臂进行分析,研究伸缩臂滑块参数对接触区域的应力影响。通过数值算例分析,当滑块长度在100~280 mm内增加时,伸缩臂应力、滑块应力、接触应力逐渐减小;当滑块长度再增加,对伸缩臂应力和接触应力影响很小,而滑块应力出现了小幅度增大。在对弹性模量局部应力的影响分析中,随着滑块弹性模量的增大,伸缩臂的局部应力也逐渐增大。

Telescopic boom is an important part of truck crane,which can transport goods by luffing,telescoping and slewing,so its structure determines the lifting performance of the crane.The load is mainly transmitted between the telescopic arms of each joint through the contact between the arm joint and the slider.The stress in the contact area between the telescopic arm and the slider is complex,and the stress in the contact area is significantly higher than that in other parts,so this area has a great influence on the overall bearing capacity of the boom.In this paper,the finite element contact theory is studied,and the finite element model of the arm joint and the slider is established by the finite element software Ansys.The contact between the arm joint and the slider is simulated by surface-to-surface contact,and the telescopic arm is analyzed under several typical working conditions to study the influence of slider parameters of the telescopic arm on the stress in the contact area.And numerical calculation and analysis show that when the length of the slider increases within 100-280 mm,the stress of the telescopic arm,the slider stress and the contact stress gradually decrease.Then,with the increase of slider length,the influence on the stress of telescopic arm and contact stress is small,while the slider stress increases slightly.Analysis of the influence of local stress of elastic modulus shows that the local stress of telescopic arm will increase with the increase of elastic modulus of slider.