共查询到20条相似文献,搜索用时 15 毫秒
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热镀锌机组沉没辊系在锌锅内工作状态下受力情况复杂,受外界影响较大。充分考虑热镀锌机组设备与其工艺特点,首先分析沉没辊系在工作状态下受力情况,分别建立矫正辊插入量与包角的关系式、基于辊面锌渣沉积厚度的辊面摩擦因数经验模型。随后采用条元离散法建立沉没辊系辊面接触压力、摩擦驱动力矩模型,基于简支梁模型确定沉没辊系轴端支撑力、轴端摩擦阻力矩模型。最后将沉没辊系受力模型应用于国内某热镀锌机组镀锌工艺段,以典型规格带钢确定沉没辊系受力影响因素,并依据机组实际工况及板形要求来确定生产工艺参数的5种不同水平,来分析其对辊系受力状态的影响规律,为沉没辊系工艺优化提供指导依据。结果表明,4种工艺参数对辊系接触压力及摩擦力矩影响都存在差异性,矫正辊插入量与辊面接触压力呈现非线性关系;带钢张力对各辊接触压力影响程度不同,其中沉没辊受到的影响最大,而其余两辊受到张力几乎不影响;辊面平均摩擦因数、带钢速度对辊的接触压力几乎不影响;辊系摩擦驱动力矩、轴端摩擦阻力矩随着矫正辊插入量及辊面平均摩擦因数增大都呈现出不同程度增大。带钢张力与沉没辊摩擦驱动力矩、轴端摩擦阻力矩呈线性变化关系,而带钢张力对其余两辊影响很小。带钢... 相似文献
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Roller pass is one of the key factors affecting the product quality in the retained mandrel rolling process. The metal flow condition of rolling deformation area was researched using the FEA (finite element analysis) software Marc. The influences of the pass bottom radius, the sidewall radius, the sidewall angle, the roller shoulder fillet radius, as well as the roller gap on the rolling process under the conditions of different friction were discussed. Based on these results, the changes of the workpiece exit width, the mandrel axial force, the rolling force, and the rolling torque associated with various parameters were determined, which would provide the basis for designing the pass and determining the rolling condition reasonably. 相似文献
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A finite element model of a microindentation is developed where the scanned surface topography data which represent the actual surface-roughness values are used in the construction of the finite element model of the workpiece. Indentation simulation with friction effect solely due to the surface deformation produces results which match the experimental ones in terms of residual indent size and pile-up heights. A roughness-dependent friction model is developed, which is comparable with the models proposed by Johnson (1985) and Alcála (2004). 相似文献
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《Baosteel Technical Research》2010,(Z1):64
Based on the ABAQUS explicit dynamic simulation platform,the finite element model of single stand mill with restrained mandrel was adopted to research the influence of mandrel - roller velocity ratio (MRVR),mandrel friction and tension between stands on rolling force.The analysis results show that when the MRVR is lower than 1,the rolling force increases obviously with the increase of MRVR and reaches the peak value when the MRVR is about 1.The rolling force increase induced by the MRVR increase is the main reason of the formation of the bulge defect on the tube head and tail at the entering and exiting stage during tube continuous rolling process by full floating mandrel mill,which can be intensified by the increase of mandrel friction coefficient.The rolling force decreases with the increase of tension.As the tension is larger, the rolling force decrease amplitude is larger.The influence of backward tension on rolling force is greater than that of forward tension distinctly.Tension control can be used to decrease the rolling force increase induced by the MRVR increase,which is imposing tension at the same time when the MRVR increases,in order to improve even eliminate the bulge defect,and enhance the tube dimension precision. 相似文献
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The transient finite element technique is applied,and a transient heat conduction model of wet brake friction disk is established.For obtaining the accurate heat-flow density mathematic model and avoiding possibly instable thermoelastic stress produced by the non-uniform contact pressure of friction pair,a test method is applied to collect accurate contact pressure between the dual sheet steel and friction disk in the combining process.And then the heat-flow density and transient thermo-mechanical coupling simulation are analyzed.At the same time all possible boundary conditions are considered,such as the heat generation,heat conduction problem,relation between friction and contact,variation in load and heat change problem etc.The simulation results show that the mechanical model of thermo-mechanical coupling can express well the dynamic characteristics of friction disk,and gives perfect reference for more study on thermoelastic distortion of brake friction pairs. 相似文献
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板成形中摩擦因数测定方法 总被引:3,自引:0,他引:3
采用新型摩擦因数测定装置进行了摩擦因数测定的实验研究,为进一步开展摩擦因数测定及摩擦边界的研究打下了基础,为有限元模拟的真实性提供了参考依据。 相似文献
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The finite element method (FEM) and neural network were applied for predicting the bead shape in laser spot welding of type
304 thin stainless steel sheets. The parameters of pulsed Nd:YAG laser spot welding such as pulse energy, pulse duration,
sheet metal thickness, and gap between sheets were varied for various experiments and numerical simulations. The penetration
depth and nugget size of spot welds measured for specimens without gap were compared with the calculated results to verify
the proposed finite element model. Sheet metal thickness, gap size, and bead shape of the workpiece without gap were selected
as the input variables for the back-propagation learning algorithm of the neural network, while the bead shape of the workpiece
with and without gap was considered as its output variable. Various combinations of stainless steel sheet metal thickness
were considered to calculate the laser-spot-weld bead shape of the workpiece without gap, which was then used as the input
variable of neural network to predict the bead shape for various gap sizes. This combined model of finite element analysis
and neural network could be effectively applied for the prediction of bead shapes of laser spot welds, because the numerical
analysis of laser spot welding for the workpiece with gap between two sheets is highly limited. 相似文献
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造成带钢头部翘曲的主要因素包括:板坯上下表面温度差、上下轧辊摩擦系数不等、上下轧辊辊速不等、上下辊辊径不同等。采用Marc有限元软件热力耦合分析法分析了各个影响因素对热轧带钢头部翘曲的影响规律,结果表明,翘曲量随上下表面温度差、摩擦系数比、辊速比及辊径比的增大而增大,但增大趋势各有不同。同时,提出了优化轧制规程、改善加热条件、采用适当的配辊方案、合理选择速度参数等解决带钢翘曲的措施。 相似文献
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《钛工业进展》2019,36(6):1-6
钛火是现代航空发动机的典型灾难性事故,压气机转子与静子的异常摩擦是其主要热源。采用动网格方法结合等效模型建立转子与静子试件的三维热-力-磨损耦合有限元模型,对不同摩擦接触压力和环境温度等条件下550℃阻燃钛合金TF550摩擦着火过程的温度场进行数值建模与仿真分析。结果表明,在室温、200 N摩擦接触压力条件下,TF550钛合金静子试件在7.2 s达到着火温度,此时转子试件温度仍维持在1 000 K,比静子试件低约900 K;当摩擦接触压力从200 N增大至400 N时,摩擦着火延迟时间为3.3 s;当摩擦接触压力提升至700 N时,着火延迟时间缩短至2 s以内;在823 K的环境温度下,静子试件的摩擦着火延迟时间为5 s,比室温下的摩擦着火延迟时间缩短了2.2 s;相对于环境温度的影响,摩擦接触压力对TF550钛合金摩擦着火升温速率的影响更大。 相似文献
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Xiao Yang LeMeng Zhang Heli Liu Denis J. Politis Mohammad M. Gharbi Huifeng Shi LiLiang Wang 《国际钢铁研究》2023,94(4):2200306
In hot metal forming processes, the temperature of the forming tool progressively increases under serial production conditions. Water-based two-phase lubricants may be applied to cool the forming tool and moderate temperature, in which the liquid agent would evaporate or decompose rapidly with dry matter deposited on the tooling surface during the dwelling time before the forming process commences. Herein, an interactive friction model for a two-phase lubricant is developed to predict the transient lubricant behaviors, i.e., predicting the effects of tool temperature and dwelling time on the friction coefficient evolution and lubricant breakdown. Friction tests between a warm pin and hot aluminum workpiece are conducted using the advanced friction testing system, TriboMate, to validate the modeling results. 相似文献
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为解决热轧厚壁无缝钢管横向壁厚分布不均的问题,建立三维热力耦合有限元模型,对张力减径轧制过程进行了动态模拟,并结合工业试验验证仿真模型.根据仿真结果分析了轧制过程中温度、应变和摩擦力的分布,研究了单道次轧制时金属的径向和周向流动规律,并结合整个轧制过程对金属的横向流动及壁厚不均的形成过程进行了分析,研究了轧制过程中温度对金属流动行为的影响,从而总结出横向壁厚分布不均的原因.结果表明:(1)在经过单道次轧制时,金属的周向流动为从孔型顶部流向辊缝,对应孔型角±30°位置处金属的周向流动最活跃,靠近孔型顶部和辊缝位置的金属周向流动性较差.但从整个轧制过程来看,金属总的周向流动为从孔型顶部和辊缝向孔型角±30°位置处流动,从而导致孔型角±30°位置处的壁厚比孔型顶部和辊缝位置要厚.(2)温度分布对金属横向流动有重大影响.由于塑性功换热的原因,孔型角±30°位置处金属的温度比辊缝和孔型顶部处高,此处金属较软,阻力较小,孔型顶部和辊缝处金属向此处的流动性增强,导致钢管截面呈内边方形. 相似文献
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采用常规矫直辊系矫直楔形板严重降低了楔形板矫直范围和效率,为了提高楔形板矫直厚度范围和矫直质量,提出了一种基于配合辊系(大直径矫直辊系和小直径矫直辊系)的楔形板矫直方法。首先研究了配合辊系矫直机辊径、辊距与楔形板矫直效果的关系,设计了楔形板矫直机配合辊系,给出了矫直工艺方案;然后给出了配合辊系矫直楔形板的分区原则,基于有限元法建立了基于配合辊系的楔形板矫直过程有限元模型,仿真结果与实测结果一致,验证了有限元模型的正确性;最后对基于配合辊系的楔形板矫直过程进行仿真,计算了常规辊系和配合辊系下楔形板矫直力及残余应力,分析了不同板厚分区对楔形板矫直效果的影响,结果表明,配合辊系设计方案适合楔形板矫直过程且矫直效果较好。 相似文献
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Experiments and finite element simulations were performed in order to study how the bite ratio influences the closing of inner flaws such as voids and pipes in the open die forging process. Square rolled blooms of carbon steel with a transversal hole in the centre were forged with a constant height reduction but with different bites in order to study the closing of voids during the process. Corresponding finite element simulations were performed in full 3D with full thermo‐mechanical coupling. Also the influence of the friction and of the temperature gradient in the workpiece were studied. The elimination of an artificial defect by forging was successfully simulated by the finite element method. It is established that the closure of voids is highly dependent on the bite ratio. The closure of voids under the edge of the tool is however not improved by a higher bite ratio. There is a slight tendency that the situation under the tool edge is worse when the bite ratio is increased. 相似文献