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管件电磁成形数值模拟方法及缩径变形分析 总被引:6,自引:1,他引:5
随着电磁成形工艺应用的发展,需要强有力的数值模拟方法来预测成形过程,并用来指导成形系统设计.归纳了现有的电磁成形模拟方法及各自的特点,讨论了模拟中存在的问题和面临的挑战.应用FEM软件ANSYS对铝合金管件电磁缩径成形进行了数值模拟,研究了管件均匀缩径变形规律.变形管坯轮廓验证了电磁缩径成形的模拟结果. 相似文献
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管材内高压成形多步法数值模拟 总被引:1,自引:0,他引:1
利用动态显式有限元程序LS-DYNA,采用多步法和单步法两种方式,以某型号副车架为例,对曲线空心构件的内高压成形过程进行了数值模拟研究,给出了两种方式下副车架内高压成形后的壁厚分布.在模拟的基础上进行弯曲、预成形和内高压成形试验,获得了副车架内高压成形件,给出了典型截面的壁厚分布,并与两种模拟结果进行了比较.结果表明,采用多步法数值模拟技术模拟曲线空心构件的内高压成形过程,考虑了弯曲和预成形对后续的内高压成形过程的影响,模拟结果与试验结果基本吻合,能够更加准确地反映曲线空心构件的内高压成形过程. 相似文献
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目的解决锥盒形件传统拉深成形十分困难,废品率高,成形质量差的问题。方法介绍了充液成形工艺的2种方式,即主动式充液成形和被动式充液成形,并利用有限元软件Dynaform对各充液成形方案进行了数值模拟。结果通过模拟分析,明确了2种充液成形方式的优缺点,提出了被动式-主动式充液成形方案,并进行了数值模拟验证;合理的预成形凸模圆角大小是A侧长边底部圆角R=40 mm,B侧长边底部圆角R=30 mm,其他底部圆角R=15 mm。结论充液成形技术与传统拉深相比,具有一定的优势;被动式-主动式充液成形方案数值模拟结果良好;预成形形状对终成形有很大的影响,改变预成形凸模圆角可控制各侧补料量。 相似文献
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板料渐进成形数值模拟与实验研究 总被引:1,自引:0,他引:1
为提高渐进成形的成形效率和成形质量,了解板料渐进成形的变形规律及工艺参数对成形的影响,采用有限元方法对板料渐进成形过程进行了数值模拟研究,分析了斜壁盒形件渐进成形过程应力分布和厚度变化趋势,通过对不同进给量和不同成形路径进行数值模拟,分析了工艺参数对成形的影响.结果表明,斜壁盒形件最大应力和最大厚度减薄发生在底面拐角处;成形过程中工具头运动轨迹应尽量采用走螺旋线的方式,可以提高成形件的成形能力和成形质量.渐进成形实验表明,数值模拟结果与实验结果基本吻合. 相似文献
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微成形技术具备高生产效率、高材料利用率和优异的成形质量,是一种极具发展前景的高精度加工技术。数值模拟技术作为一种先进的研究手段,可以在塑性加工中对材料的变形和工艺可行性等进行评估和预测,达到节约生产成本、缩短研发周期的作用。主要综述了数值模拟技术在微成形研究中的典型应用。介绍了数值模拟技术在研究材料性质和材料变形方面的应用,包括利用Voronoi方法和晶体塑性方法建立金属多晶体模型,研究了微成形过程中材料的变形机制和尺寸效应,建立了材料摩擦函数、构建了零件粗糙表面,研究了微成形过程中的摩擦行为;将晶粒大小、晶体取向与板料模型相关联,研究了微成形过程中薄板的回弹行为和成形极限。除此之外,也介绍了近年来微成形领域的许多新成形技术,如激光辅助微成形、水射流增量微成形、超声辅助微成形,以及数值模拟方法在这些新微成形技术方面的应用。最后,总结了数值模拟技术在微成形研究中所起的作用,并展望了该领域的未来发展趋势。 相似文献
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目的预测高强度钢板的冲压成形性。方法对使用高强度材料的左前地板2号横梁进行了数字仿真模拟,设计了一种提高板料抗破裂性能的带氮气弹簧的预成形模具。先根据仿真结果,在采用调整工艺参数的常规手段未果的情况下,分析了破裂原因,再根据成形模拟软件的使用要求,对氮气弹簧的技术特性进行了处理,保证能代入成形软件。结果再次成形模拟证明,采用氮气弹簧的预成形模具,能改善模具受力状态,使成形件不致破裂。结论预成形模具结构有助于改善特定形状冲压件的成形性。 相似文献
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AbstractObjectives were to study mechanical properties of various solid forms of paracetamol and relate to their crystal structures. Paracetamol form I (PRA), its cocrystals with oxalic acid (PRA-OXA) and 4,4-bipyridine (PRA-BPY) and hydrochloride salt (PRA-HCL) were selected. Cocrystals and salt were scaled-up using rational crystallization methods. The resulting materials were subjected to different solid-state characterizations. The powders were sieved and 90–360?µm sieve fraction was considered. These powders were examined by scanning electron microscopy (SEM) and densities were determined. Tablets were made at applied pressures of 35–180?MPa under controlled conditions and the tablet height, diameter and hardness were measured. Tensile strength and porosity of the tablets were estimated using well known models. Crystal structures of these systems were visualized and slip planes were identified. Cocrystal and salt of PRA were physically pure. Sieved powders had comparable morphologies and particle size. The apparent and theoretical densities of powders were similar, but no clear trends were observed. The tensile strengths of these compacts were increased with increasing pressure whereas tabletability decreased in the order oxalic acid?>?PRA-HCL?≈?PRA-OXA?>?BPY?>?PRA-BPY. Tablet tensile strength decreases exponentially with increasing porosity with the exception of PRY-BPY and BPY. Slip plane prediction based on attachment energies may not be independently considered. However, it was possible to explain the improved mechanical properties of powders based on the crystal structure. Cocrystallization and salt formation have introduced structural features that are responsible for improved tableting properties of PRA. 相似文献
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对圆柱形金属橡胶结构做静态实验,运用最小二乘法对实验数据进行拟合,得到金属橡胶材料本构方程的各系数,将由实验得到的各系数代入本构方程式中,从而得到理论拟合迟滞回线,将理论拟合迟滞回线与试验迟滞数据进行对比,发现理论拟合迟滞回线与试验迟滞数据吻合较好,同时运用ANSYS有限元软件对金属橡胶结构进行有限元建模、定义边界条件及施加载荷,最后进行应力应变分析,得到应力应变分布图,发现分析结果与实验结果吻合。 相似文献
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Bogumi? Wronka 《International Journal of Impact Engineering》2011,38(5):309-313
The basic defects occuring in explosive clad plates were properly systemized and the reasons of their formation were explained. Cases of cracks and delaminations in explosive clad plates were examined in this work. Various values of tensile stresses coming from loading and unloading waves were analysed, as they were the main reason of defects. The defects were connected with properties of welded materials in the joint area and beyond it. Some practical aspects of this process were shown as well. 相似文献
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应用在食品行业中的冷封胶薄膜 总被引:6,自引:1,他引:5
概述了冷封胶薄膜的结构种类、制备工艺以及优点,接着陈述了冷封薄膜在软包装中的应用以及局限性,指出了实际生产中遇到的问题并对问题进行分析,提出改进方法.最后探讨了冷封薄膜未来的发展方向. 相似文献
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Single crystals of calcium iodate and barium iodate were grown by simple gel technique by single diffusion method. The optimum
conditions were established by varying various parameters such as pH of gel solution, gel concentration, gel setting time,
concentration of the reactants etc. Crystals having different morphologies and habits were obtained. Prismatic, dendritic
crystals of barium iodate and prismatic, needle shaped, hopper crystals of calcium iodate were obtained. Some of them were
transparent, some transluscent, and few others were opaque. Both the crystals were studied using XRD, FT-IR, and thermal analysis.
The crystals were doped by iron impurity. The effect of doping was studied using IR spectroscopy and thermal analysis. 相似文献
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在制取力学性能试样的机械加工中常发现试样有不同程度的弯曲与扭转变形,严重影响试样加工精度和力学性能测试的准确性。对宽带试样变形的产生原因及其对试样机械加工质量的影响进行了分析,并提出了相应措施,取得了较好的效果,保证了加工质量,提高了加工速度。 相似文献
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Mixed crystals of calcium-cadmium iodate were grown by a simple gel technique using diffusion method. The optimum conditions
were established by varying various parameters such as pH of gel solution, gel concentration, gel setting time, concentration
of reactants etc. Crystals having different morphologies and habits were obtained. Prismatic, dendritic crystals of calcium-cadmium
iodate and prismatic needle shaped, hopper crystals of mixed iodate were obtained. Some of them were transparent, some transluscent
and a few others were opaque. The crystals were characterized using FT-IR, EDAX, XRD, TGA and DTA. 相似文献
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阐述和分析了CTP技术的发展情况及特点;探讨了目前CTP发展中存在的认识不高、缺乏政策导向、设备版材配套研发不够、机制问题引起的市场恶性竞争问题突出和数字化环境建设及技术人才培养不够4个方面问题,并提出了发展对策;指出并分析了CTP技术4个主要发展动向:紫激光、热敏CTP发展迅速;外鼓式制版机成为主流;光敏型CTP版材紫激光光聚合版将成为主流;热敏型CTP版材免处理版方兴未艾. 相似文献