牧草压缩过程应力松弛试验研究及压缩活塞的力学分析

应力松弛是牧草压缩过程中显著的流变学特性。研究压缩室不同截面下的应力松弛特性,可为牧草压捆机的压缩频率的确定提供理论依据。为此,以高密度压捆机为试验装置,以羊草为试验材料,分别以360mm×4 4 0 mm、3 6 0 mm×4 5 0 mm、3 6 0 mm×4 6 0 mm这3种压缩室截面进行试验,获得了压缩室不同截面下应力松弛特性。试验表明:在不同截面下开始应力松弛的前3s应力松弛明显,在3s之后应力随时间的推移而松弛放慢,超过10s应力松弛速率趋于水平,从尽可能使草片有较充分应力松弛和保证较高的生产率的综合角度出发,在实际牧草压缩生产中将压缩频率选在3~10s之间较合理。在试验的基础上,对压捆机压缩活塞进行力学分析,寻找出了压缩活塞工作过程中最容易变形的部位,为压捆机压缩活塞的设计及结构强度校核等提供了依据。

Experimental Study on Stress Relaxation of Forage in Compression Process and Mechanics Research of Compression Piston

In order to study pasture stress relaxation characteristics at different compression section, the paper studies the stress relaxation test high density baler machine leymus chinensis at different compression sectional utilization. Select 360mm×440mm,360mm×450mm,360mm×460mm three compression section leymus chinensis were fed an amount of stress relaxation tests 3kg, access to the stress relaxation characteristic curve under different sections through the test, the baler compression frequency compression chamber length parameter determination to provide a theoretical basis. Tests showed: stress relaxation before 3 seconds starting at different sections of the obvious stress relaxation after 3 seconds stress relaxation over time and slow down, more than 10 seconds stress relaxation rate tends to level, from as much as possible a more grass sheet fully integrated stress relaxation and ensure higher productivity angle of view , in the actual production of forage compression will compress selected frequency between 3 ~10 seconds is more reasonable. On this basis, using for mechanics analysis for compression piston of baler. Find out the most easily deformed parts in the work-ing process of the compression piston. The conclusions for compression piston structure design and structure strength pro-vide the basis for calibration.