销齿副销齿和轮齿弯曲应力有限元分析

对于常用齿轮轮齿弯曲应力的有限元分析已多有研究,但对于应用日渐广泛的销齿传动的销轮销齿和齿轮轮齿弯曲应力有限元分析迄今尚未见报导。本文将Pro/E和ANSYS相结合,对销齿副销齿和轮齿弯曲应力进行了有限元分析,得出了弯曲应力等值分布图,为销齿传动的精确设计及弯曲应力的深入研究提供了有益的分析数据。     

电解锰渣制备微晶玻璃正交实验研究

将煅烧后的电解锰渣作为单一的实验原料,采用烧结法,制备微晶玻璃,通过正交实验对锰渣微晶玻璃的热处理方案及性能进行探讨。实验通过DSC、XRD、SEM等方法对样品的性能进行表征,并测试了样品的体积密度、抗弯强度等性能。结果显示:不同的热处理条件下的锰渣微晶玻璃的主晶相均为透辉石(含铁),次晶相为普通辉石相。在800℃/0.5 h+980℃/1 h的热处理条件下得到的锰渣微晶玻璃的综合性能最优,其抗弯强度为106.82 MPa;体积密度为2.68 g/cm^3;维氏硬度为4.43 GPa;耐酸度为0.71%;耐碱度为0.07%。此外,锰渣微晶玻璃用作建筑材料,有非常大的应用潜力。     

Investigating the effect of SPRM on mechanical strength and thermal conductivity of highly porous alumina ceramics

For recycling waste refractory materials in metallurgical industry, porous alumina ceramics were prepared via pore forming agent method from α-Al₂O₃ powder and slide plate renewable material. Effects of slide plate renewable material (SPRM) on densification, mechanical strength, thermal conductivity, phase composition and microstructure of the porous alumina ceramics were investigated. The results showed that SPRM effectively affected physical and thermal properties of the porous ceramics. With the increase of SPRM, apparent porosity of the ceramic materials firstly increased and then decreased, which brought an opposite change for the bulk density and thermal conductivity values, whereas the bending strength didn’t decrease obviously. The optimum sample A2 with 50 wt% SPRM introducing sintered at 1500 °C obtained the best properties. The water absorption, apparent porosity, bulk density, bending strength and thermal conductivity of the sample were 31.7%, 62.8%, 1.71 g/cm³, 47.1 ± 3.7 MPa and 1.73 W/m K, respectively. XRD analysis indicated that a small quantity of silicon carbide and graphite in SPRM have been oxidized to SiO₂ during the firing process, resulting in rising the porous microstructures. SEM micrographs illustrated that rod-like mullite grains combined with plate-like corundum grains to endow the samples with high bending strength. This study was intended to confirm the preparation of porous alumina ceramics with high porosity, good mechanical properties and low thermal conductivity by using SPRM as pore forming additive.     

壁厚补偿原理在R/D<2弯管制作工艺中的应用

介绍了壁厚补偿原理在R/D值较小情况下弯管制作中的应用。该方法克服了常规工艺在此情况下容易出现的问题 ,使弯管加工的各项指标均优于国家标准     

多晶氧化铝纤维对莫来石—氧化锆陶瓷材料的增强研究

以电熔莫来石、半稳定氧化锆和α-氧化铝微粉为主要原料,制备莫来石—氧化锆陶瓷材料。在材料中分别外加了（V%）0、5%、10%、15%和20%的多晶氧化铝纤维,并将试样在1500℃保温3h烧成,制备出氧化铝纤维增韧的莫来石—氧化锆复相陶瓷。研究了氧化铝纤维对试样的加热线收缩率、常温耐压强度、常温抗折强度和热震稳定性的影响。结果表明：加入适量的多晶氧化铝纤维能够显著降低莫来石—氧化锆复相陶瓷的加热线收缩率,大幅度提高其常温抗折强度和热震稳定性,而常温耐压强度只有轻微下降。     

椭圆空心截面梁侧向失稳分析

分析椭圆空心截面(EHS)构件弯曲时的侧向稳定性。对8根截面(高厚比为2)的无侧限EHS梁进行三点弯曲试验,并记录试件的试验设备、材料性质、截面几何形状、残余应力以及荷载、变形响应。使用数值模拟方法对试验数据进行补充,并依据试验结果验证其正确性。数值分析用于评估截面高厚比和构件长细比对侧向稳定性的影响。基于结构特性相关数据建立椭圆空心截面梁的侧向扭转屈曲曲线。提出限制长度以下时,侧向扭转屈曲(LTB)可不考虑。     

Computer aided engineering of the sheet bending process

The effects of the punch nose radius and sheet thickness on the elastic springback and residual stresses in the 90° V-punch and U-die bending process of AA 5083 aluminium alloy have been extensively studied by numerical simulations based on the finite element method. The results show that, irrespective of the sheet thickness and punch stroke, the springback ratio is not affected by the punch nose radius. Such results are in excellent agreement with the experimental ones obtained in similar conditions. As far as punch nose radius effects on the residual stresses are considered, significant differences were observed between residual stresses predicted with different nose radii. In particular, the shifting of the neutral layer and increase in the magnitude of the residual stresses predicted by the FEM code were found with decreasing punch nose radius.     

薄壁大直径不锈钢管的弯曲成形研究

本文主要针对薄壁大直径不锈钢管在数控弯管机成形过程中发生的多种失稳起皱、断裂等问题进行剖析,并针对各种复杂情况设计不同材料的模具,制作出适合大批量生产的工装模具。     

油孔夹环成形工艺分析及模具设计

主要介绍了油孔夹环弯曲模设计.利用仿真软件进行模拟工艺分析基础上,确定模具设计方案.采用凸模和夹块共同弯曲成形,设计弯曲模具,并解决弯曲过程中出现的问题.详细介绍了模具工作零件的设计、定位零件的设计、卸料装置的设计和模架选择等.所设计模具高效、可靠,为同类产品设计提供借鉴.     

AZ31镁合金薄板经不同累积应变的连续弯曲变形后的显微组织与成形性能

对AZ31镁合金板材进行不同累积应变的连续弯曲变形及退火处理,随后对显微组织与力学性能的变化进行了研究。结果表明:经不同累积应变的连续弯曲变形后,镁合金板材的显微组织中没有发现孪晶,退火后,板材表层的晶粒异常长大,粗晶层的厚度随着累积应变的增加而增加,并且镁合金板材的织构朝RD方向偏转,偏转角度随累积应变的增加而增大;与原始板材相比,连续弯曲变形及退火处理使镁合金板材呈现出较好的室温成形性能(杯突值由2.3 mm提高到4.9 mm,提高了~113%),这主要归因于基面织构的改善使镁合金板材的r值减小与n值增大。