薄壁件铣削动态响应与振动抑制研究

发布时间：2018-03-29 04:33

本文选题：薄壁件　切入点：移动载荷　出处：《山东大学》2017年硕士论文

【摘要】：随着现代工业的发展,薄壁零件在航空航天、汽车、能源等众多领域应用日益广泛,薄壁件加工质量和加工效率的要求也越来越高。由于薄壁零件刚度较低,在加工过程中会出现强烈的强迫振动甚至颤振。这将严重影响工件表面加工质量,并限制材料移除效率。本文围绕薄壁零件铣削动力学模型,借助理论分析和实验研究等手段,识别其瞬时动态特性,预测薄壁零件在铣削力作用下的强迫振动、铣削稳定性,并提出抑制加工振动的方法。首先,提出一种薄板受移动载荷作用时振动响应的预测方法。该方法基于利兹法和拉格朗日方程建立薄板在移动载荷作用下的动力学模型,采用Courant罚参数法处理实际工件所具有的复杂边界条件,利用微分求积法求解系统运动方程。其次,研究薄壁件铣削强迫振动响应。将刀具沿切削路径移动引起的铣削力作为移动载荷,将移除材料对系统响应的影响通过负动能和负应变能表示,研究考虑材料移除效应影响的变厚度薄壁零件在铣削力作用下的强迫响应。然后,提出时空离散稳定性预测方法预测薄壁件铣削位置依赖的切削稳定性。基于连续体动力学理论,研究薄壁件铣削系统位置依赖的动态特性,提出薄壁件铣削位置依赖的时空离散稳定性预测方法。为了获得系统能量方程并进一步推导系统频响函数,采用结构阻尼代替阻尼比用于分析阻尼对系统动态特性的影响;在获得系统频响函数基础上,研究边界条件、模态振型、刀具位置对系统模态参数和稳定性的影响。此外,研究多模态对薄壁件动态特性的影响,针对各阶模态参数之间的关系,提出多模态铣削稳定性预测方法。最后,提出基于约束阻尼结构的薄壁件铣削振动抑制方法。为了抑制加工过程中弱刚度部件的振动,将约束阻尼结构用于大悬伸比镗刀和薄壁零件,建立约束阻尼镗刀和约束阻尼薄壁件动力学模型,通过实验验证理论模型的正确性和约束阻尼结构的阻尼性能。此外,研究约束阻尼结构尺寸参数对阻尼性能的影响。
[Abstract]:With the development of modern industry, thin-walled parts are widely used in many fields, such as aerospace, automobile, energy and so on. There will be strong forced vibration or even chatter in the process of machining, which will seriously affect the quality of workpiece surface processing and limit the efficiency of material removal. This paper focuses on the milling dynamics model of thin-walled parts by means of theoretical analysis and experimental research. Identify its instantaneous dynamic characteristics, predict the forced vibration of thin-walled parts under milling force, milling stability, and put forward a method to suppress machining vibration. A method for predicting the vibration response of thin plates subjected to moving loads is proposed. The dynamic model of thin plates under moving loads is established based on the Leeds method and Lagrange equation. The Courant penalty parameter method is used to deal with the complex boundary conditions of the actual workpiece, and the differential quadrature method is used to solve the equations of motion of the system. The forced vibration response of thin-walled milling is studied. The milling force caused by the tool moving along the cutting path is taken as the moving load, and the influence of the removed material on the system response is expressed by negative kinetic energy and negative strain energy. The forced response of thin-walled parts with variable thickness under milling force considering the effect of material removal is studied. A spatio-temporal discrete stability prediction method is proposed to predict the position dependent cutting stability of thin-walled milling. Based on continuum dynamics theory, the dynamic characteristics of position dependence of thin-walled milling system are studied. In order to obtain the energy equation of the system and to deduce the frequency response function of the system, the influence of damping on the dynamic characteristics of the system is analyzed by using the damping ratio instead of the damping ratio. On the basis of obtaining the frequency response function of the system, the effects of boundary conditions, modal modes and tool positions on the modal parameters and stability of the system are studied. In addition, the effects of multi-mode on the dynamic characteristics of thin-walled parts are studied. According to the relationship between various modal parameters, a multi-mode milling stability prediction method is proposed. Finally, a vibration suppression method for thin-walled parts based on constrained damping structure is proposed. The constrained damping structure is applied to the large suspension ratio boring tool and thin-walled parts, and the dynamic model of constrained damping boring tool and constrained damping thin-walled part is established. The correctness of the theoretical model and the damping performance of constrained damping structure are verified by experiments. The effect of size parameters of constrained damping structure on damping performance is studied.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG54

【相似文献】