秸秆捆扎绳环结扣稳定性的力学条件

Mechanical Conditions of the Stability of the Knot on Ropes for Straw Bundled

为了提高秸秆压捆过程中捆扎绳结扣的稳定性,减轻结扣对绳环抗张强度的削弱,提高打捆绳利用效率,通过分析成结及预紧过程中打捆绳结扣处的受力、变形及断裂状态,研究了不同α结稳定所需的力学条件;考察了α结稳定前提下的绳环断裂规律,预估了3种常用打捆绳采用不同结扣环接时可用的极限抗张强度。在进行相关力学试验后发现:绳环的强度薄弱处均出现在结扣处,抗张强度仅为打捆绳极限强度的40%～60%;α活结较α死结成结所需预紧力均有明显下降,采用α活结环接绳环时抗张强度提高10%。在此基础上,提出了3条捆扎绳适宜的结扣形式、预紧条件以及打捆绳应有的结构和力学特性的建议。

In order to improve the stability of knot on ropes for bundling in the process of compressing Straw,reduce the effect that knot weaken tensile strength,and improve the efficiency of using ropes.By means of analyzing force,transfiguration and the phenomena of rupture of knot on ropes for bundling in the process of knot-form and pre-tightening,this paper investigates the mechanical conditions that different αknot need to be stable,studies the breaking pattern of knot on ropes on the basis of stabilization of α knot,and predicts tensile strength of 3 different usual ropes for bundling in different knot manner.Based on some mechanics relevant experiments,it is discovered that the weak point of rope present to the knot.The tensile strength accounts for only 40% to 60% of the high-point strength,αslipknot need much less pretightening force than α knot.Using α slipknot can raise tensile strength at about 10%.On such basis,suggestions about feasible manners of knot of 3 different ropes,the condition of pre-tightening,due structure and Mechanical properties of ropes are provided.