影响金刚石圆锯片切割因素的探讨

金刚石圆锯片割石材实际是刀头对石材磨削和破损的过程，而圆锯片基体是承受力的支体。锯片的切削量、转速、走刀速度和切深有机互相配合是我们正确选择切割工艺的目的。因此，对它们在切割过程中的关系有深刻理解是必要的。     

浅述金刚石圆锯片基体张力处理技术

1引言 金刚石锯片被广泛应用于石材开采切板、建材切割、工程施工等领域,在使用过程中,基体处于高速旋转的工作状态,受离心力、切削力、热应力等多种载荷作用,局部会形成不同的应力区,从而可能会导致轴向变形,或者切割时会发生锯片抖动或跳动的现象.这种不稳定现象会导致切割对象切面不齐整、切缝超宽,造成材料浪费或者报废,同时也会影...     

抗裂圆环的干缩应力分析 Ⅰ.均匀干燥时的理论分析

利用弹性力学方法分析了抗裂圆环在水泥基材料发生均匀干缩变形时的径向位移分布、径向应变分布、环向应变分布、径向应力分布和环向应力分布。给出了这些分布的数学表达式,并对这些表达式进行了分析。研究结果表明,在均匀干燥过程中,水泥基材料圆环径向受压,环向受拉,最大环向拉应力在圆环的内侧。环向应变是多种应变的叠加,而不仅是环向拉应力作用的结果。     

“三明治”复合金刚石圆锯片基体点焊变形的原因及控制措施

正目前,国内外"三明治"金刚石圆锯片基体层与层之间的连接普遍采用点焊的方式进行连接,根据不同厚度、不同大小规格,采用不同的点焊参数,不同的焊点距离进行点焊,起到把两层钢板和一层铜皮介质连在一起的作用。在点焊过程中往往由于急剧的非平衡加热及冷却,锯片将不可避免地产生点焊残余变形。点焊残余变形是影响"三明治"金刚石圆锯片基体内在质量的关键因素,直接影响锯片基体的张力、     

如何使用金刚石薄型圆锯片

几年来,通过黑旋风对薄型锯片基体的技术创新和昆玉石材锯片有限公司对薄型圆锯片刀头的研究,使石材加工工艺水平和板材质量均有较大的提高。本公司在金刚石薄型圆锯片的使用过程中,认为金刚石薄型圆锯片在圆盘锯的石材生产中起到了很大的作用,既节约了成本,又提高工作效率。现就如何使用     

金刚石锯片齿部裂纹机理分析及防范措施

<正>前言从金刚石锯片本身的结构及工作状况可知，金刚石圆锯片的齿距一般是周向等间距分布的，在特定的切深下，必然导致同时工作齿数周期性的变化，锯片的应力也相应变化；而能量消耗的变化也导致热应力的变化，使其整体受力明显具有动力学特征。此外，对每个锯齿而言，刀齿与工件材料的接触是分离→逐渐接触→切削→逐渐分离→分离的过程，使锯片局部受力又具有周期特征。因此，     

解决石板材弯曲问题的方法

正为了解决石板材弯曲问题,首先来分析锯片方面的因素:圆盘锯石机用加圆锯片是由基体和金刚石刀头焊接而成的,锯片的质量高低取决于基体的质量,刀头的质量以及基体和刀头的焊接质量。(1)锯片基体:一般情况下,新的锡片基体在基体制造厂出厂前都进行张力值的控制和平面度和端面跳动量的控制。但是有的基体在石材厂     

抗裂圆环的干缩应力分析Ⅳ.不均匀干燥时干缩应力的理论分析

用弹性力学方法分析了抗裂圆环在水泥基材料发生不均匀干缩变形时的径向位移分布、径向应变分布、环向应变分布、径向应力分布和环向应力分布。给出了这些分布的数学表达式,并对这些表达式进行了分析。研究结果表明,在不均匀干燥过程中,水泥基材料圆环径向受压、环向受拉、最大环向拉应力在圆环的外侧。     

浅谈金刚石圆锯片焊接强度的检测

本文论述了用扭力扳手检测金刚石圆锯片焊接强度的原理,分析了金刚石圆锯片掉齿的原因,浅析了其它几种不同应力计算公式在推导原理上存在的缺陷。用本文推荐的应力计算公式得出的参考扭矩去检测锯齿的焊接强度,在很大程度上可解锯片掉齿问题,为金刚石圆锯片的使用提供了安全保障,也保证了金刚石圆锯片的锯切性能。     

基于有限元理论分析掏孔对金刚石圆锯片刚度的影响

正金刚石圆锯片具有优越的切割性能,兼有使用方便、加工效率高等优点,被广泛应用于石材加工、建筑施工等国民经济领域,并且随着金刚石圆锯片制作技术的不断进步及成本持续降低,它的应用领域还在扩大,需求量在继续增加。同时,人们对金刚石圆锯片的结构和锯切性能,对环保以及降低总体成本等因素的要求越来越高,使人们越来越重视通过合理设计金刚石锯片基体结构来降低加工成本、提高生产效率、减小振动、降低噪音污染。     

金刚石圆锯片切割石材及有限元分析

通过XK5032C型数控铣床进行切削花岗石试验研究,主要考察了加工参数对圆锯片切削力的影响,确定了金刚石圆锯片切削花岗石时加工参数对切削力的影响规律。切削力的大小随着切削深度和进给速度的增加而增大,而随着主轴转速的增大而减小。通过ANSYS软件进行了有限元分析,研究在不同的加工参数下,金刚石圆锯片实际受力情况,分析其中的变化规律。     

φ1600mm金刚石圆锯片的有限元分析

本文采用有限单元法对金刚石锯片应力及振动进行了系统的分析,并找出其一般规律。     

锯切花岗岩用金刚石有序排列锯片的研制

本文叙述了金刚石均匀分布／有序排列的优越性,引用信息产业集成电路的先进制造技术与工艺研制成锯切花岗岩用金刚石有序排列锯片。对比实验表明,在相同胎体配方与工艺条件下,有序排列锯片的锯切效率比常规锯片提高20％-30％,锯切速度高达7m／min以上。在我国金刚石工具行业中采用与推广金刚石有序排列锯片将具有重大意义。     

Investigation on swelling-shrinkage behavior of unsaturated compacted GMZ bentonite on wetting-drying cycles

It is generally recognized that swelling/shrinkage deformation and accumulative deformation of compacted expansive soil on wetting-drying cycles are strongly influenced by the specimen’s dry density and the net stress applied. However, investigations on the coupling effects of dry density and vertical net stress on the swelling/shrinkage deformation and accumulative deformation are limited. Cyclical wetting-drying tests were conducted on unsaturated compacted GMZ bentonite specimens with three dry densities under five vertical net stresses. The influence of vertical stress on accumulative deformation was analyzed. Then, the critical vertical stress was proposed for specimens with different dry densities. The effect of dry density on accumulative deformation was studied and the critical dry density was determined for different vertical stresses. Based on these, the concept of critical swelling-shrinkage line is proposed in the e-p space. According to the relationship between the initial state of specimen and the critical swelling-shrinkage line, a state parameter is proposed for determination of the accumulative strain on wetting-drying cycles.

     

Experimental study of the natural frequencies of rotating thin-walled composite blades

The paper presents an experimental method for detecting the natural frequencies of helicopter-like thin-walled rotating composite blades, and a study of their dependency in the lamination angles and in the rotor angular velocity. The tests were carried out in a vacuum chamber which allowed the isolation of the structural dynamic effects. Both symmetric and antisymmetric box-beam specimens were tested. The blades were excited by an impulse force during rotation and the time history of the resulting strain distributions were recorded. Natural frequencies have been obtained by numerical analysis of the time response. The results demonstrate high repeatability and clear trends of the natural frequencies variation as a function of the blade lamination modes and their angular velocity.     

盾构机切刀切土过程的有限元模拟分析

采用有限元方法数值模拟了盾构机刀盘切刀的切土过程。采用Drucker-Prager本构模型表征土体的非线性变形特性。讨论了如何将土体直剪实验得到的抗剪指标参数转换为ABAQUS软件的3个塑性指标的方法。有限元分析结果仿真再现了在刀盘切刀作用下的土体破碎过程。在开始时刻,在切刀与土体的接触面产生较大的应力。随着切刀的继续向前推进,最大等效应力位置已经转移到切刀前方大约45°方向。研究结果表明,在切刀启动阶段,切刀切土阻力近似为平稳阶段的4倍。本研究可以为刀盘切刀的优化布置和盾构机掘进参数的合理设定提供借鉴和参考。     

Impact analysis of compressor rotor blades of an aircraft engine

Frequent failures due to foreign particle impacts are observed in compressor blades of the interceptor fighter MIG-23 aircraft engines in the Ethiopian air force, supplied by the Dejen Aviation Industry. In this paper, we made an attempt to identify the causes of failure and hence recommend the suitable materials to withstand the foreign particle impacts. Modal and stress analysis of one of the recently failed MIG-23 gas turbine compressor blades made up of the following Aluminum based alloys: 6061-T6, 7075-T6, and 2024-T4, has been performed, apart from the impact analysis of the rotor blades hit by a granite stone. The numerical results are correlated to the practical observations. Based on the modal, stress and impact analysis and the material properties of the three considered alloys, alloy 7075-T6 has been recommended as the blade material.     

银川火车站跨线钢结构天桥温度效应分析

均匀的温度场变化会对超静定结构产生不利影响,被约束结构在温度作用下会发生变形并产生内力。本文研究银川火车站跨线钢结构天桥网架在外界温度应力场作用下产生的内力和变形对网架的影响,利用Midas Civil有限元软件对该网架进行静力和温度应力计算,通过结果分析,总结温度应力场对网架结构的影响。     

Coupled CFD–FE analysis for the exhaust manifold to reduce stress of a direct injection-diesel engine

The present work deals with the investigation of the exhaust manifold of a four-cylinder diesel engine. Geometry creation and finite element method of the exhaust manifold was done using Computer Aided Design and CAE software. To simulate the thermal boundary coefficients of the exhaust manifold wall under steady-state loading conditions, the internal flow field structure was obtained using Computational Fluid Dynamics (CFD) software. The thermal boundary conditions were mapped to structural element surfaces of the exhaust manifold based on commercial finite element code ABAQUS. Thermal analysis was conducted to find out the high thermal stress areas. Design modifications were done on the high stress area and the process was repeated and stresses were reduced to meet the target. Numerical results and contour plots were reported on. The analysis of such a system is critical due to the complexity of meeting the structural and flow requirements. The use of coupled CFD and FEA simulation gives a better prediction of thermal stresses and flow behaviour in the exhaust manifold. The simulation captures the stress pattern and stress concentration at the failure location. The modification has reduced the stress level by 13% and eliminated the stress concentration.     

桅杆结构的非线性分析

本文叙述了按空间受力状态,采用矩阵位移法对桅杆结构进行精确的非线性分析问题。文中给出的计算公式可适用于一般情况下平地与山地桅杆的静力、温度应力、支座沉降、自振特性和抗地震计算。本文的结构分析考虑了桅杆杆身的轴向变形,纠正了计算桅杆温度应力所沿用的不确切的分析方法。文中的理论分析得到了模型试验的验证。首都323米大气污染监测塔的结构计算,采用了本文的计算方法及其计算机通用程序。