高频响电液伺服加载系统安装机架的结构优化方法

Structural Optimization Scheme of Mounting Rack in High-frequency Electro-hydraulic Servo Loading System

在高频重载电液伺服加载系统中,其安装机架的变形和振动会限制系统的频宽,尤其当进行高频简谐加载时,产生的冲击载荷使机架发生谐振,加剧了机架的变形和振动,严重时甚至破坏系统的稳定性。以采用十字形横梁为机架的单摆负载电液伺服加载系统为例,利用Abaqus软件对机架结构进行了模态及谐响应分析,通过分析机架在油缸简谐激振力作用下的谐振特性,获得机架各部分结构振动的强弱分布及抗振薄弱区位置,由此提出了提高机架刚度的抗振加固方案,将原十字形横梁改为对角结构,在抗振薄弱区增加筋板,构建三角结构。优化后的方案使机架一阶固有频率从141 Hz提高到190Hz,满足了系统的频宽要求。

In the high-frequency and overloads electro-hydraulic servo loading system,the distortion and vibration of mounting rack would limit the bandwidth of system,especially in the situation of carrying out high-frequency harmonic loading,the resulted impulsive load would cause the resonance oscillation and aggravate the distortion and vibration of mounting rack,even destroy the system stability.By taking the pendulum load electro-hydraulic servo loading system which adopted a cross beam as mounting rack as example,the modal and harmonic response analysis towards the structure of mounting rack was carried out using Abaqus software.By analyzing resonance oscillation characteristics of mounting rack under the effect of oil cylinder's harmonic excitation force,obtained the strength distribution of the various parts of mounting rack and the weak position of vibration zones were obtained.So,when designing the mounting rack of this system,the most important are finding the strength distribution of the various parts of mounting rack,screening out the weak position of vibration zones and conducting structural optimization.Thus the shakeproof reinforcement scheme was proposed to improve the stiffness of mounting rack,the original cross beam was changed to diagonal structure,and added the rib in the weak vibration areas and built triangular structure.The optimized schemem has made the first order inherent frequency of mounting rack raisen from 141 Hz to 190 Hz,and satisfied the bandwidth requirements of the system.