共查询到20条相似文献,搜索用时 141 毫秒
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以中厚钢板为研究对象,采用数学公式推导和实验相结合的方法,在弯曲过程中分析应力和应变中性层内移的基础上,根据弯曲前后体积不变、内外边层应变绝对值的增量与它们到应力中性层的距离成正比这两个条件,推导板厚变化与相对弯曲半径的关系式.比较实验值与公式推导的板厚变化值,得出板厚变化值的经验修正系数,并通过Abaqus软件对选定材料的弯曲进行数值模拟,验证计算方法的正确性. 相似文献
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注塑制品往往具有复杂的几何形状,存在着壁厚的差异。三维流动模型比二维模型能更准确地模拟出熔体充模流动的情况。提出了一种基于全三维模型的注塑成形流动模拟的数学模型和数值实现方法,把速度和压力同次插值的方法成功地应用到三维注塑模拟的计算中,采用三维控制体积追踪塑料熔体的流动前沿,在温度场计算中,全面考虑了对流项在各个方向的影响,使模型的适用范围更广,结果更准确。在此基础上开发了相应的软件,可以计算熔体充模过程中的压力场、速度场和温度场等。实验验证和算例分析说明了三维流动模型的有效性。 相似文献
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建立了车用催化转化器蜂窝载体的流体动力学模型,采用CFD软件对催化转化器的流场进行了二维稳态流动数值模拟,分析和评价了催化转化器的设计性能和试验方法,为催化转化器的结构优化设计提供了依据。 相似文献
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基于多相流动的拉格朗日离散相模型,应用FLUENT软件对前混合磨料射流出口带圆柱段的圆锥收敛形喷嘴内部等温、不可压缩、稳态、液固湍流进行了数值模拟。连续相采用三维不可压缩稳态雷诺时均N-S方程,湍流模型采用标准的肛£模型,代数方程组采用分离解方法,通过SIMPLE算法求解压力速度耦合;离散相采用拉格朗日方法追踪颗粒运动轨迹;收敛残差为10^-4。给出了颗粒初始位置对颗粒的运动速度和运动轨迹的影响规律,数值模拟结果对前混合磨料射流喷嘴的优化设计和工程应用具有很好的指导意义和参考价值。 相似文献
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塑料注射成形过程仿真软件的开发和应用 总被引:6,自引:1,他引:5
智能型3维注射成形过程仿真系统HSCAE 3D解决了用3维实体/表面模型取代中性层模型的关键性技术难题,通过数值计算与人工智能技术的结合,使仿真软件由传统的被动式计算工具提升为主动式优化系统。实验和实践证明,HSCAE 3D为注塑制品与模具的虚拟制造奠定了坚实的理论和技术基础,构成了注塑制品成形质量全面控制的核心技术,已在模具行业中得到了很好的应用。 相似文献
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G. Thimm F. Jiang T.S. Beng G. Britton 《The International Journal of Advanced Manufacturing Technology》2002,20(6):429-438
A new generic graph representation scheme for process planning is presented. It has been specifically developed to facilitate
the planning and control of geometric dimensions and tolerances. Relationships between cut, location, and datum surfaces and
machining operations are represented by a graph consisting of connected boxes. A box is a multi-terminal node that corresponds
to a machine set-up. Machining operations are depicted as arrows inside the box. These connect input nodes, representing datum
and location surfaces, to output nodes, representing machined surfaces. External connectors join boxes together to form a
directed graph. The main purpose of these connectors is to indicate the surfaces (from prior set-ups) that are used as location
and datum surfaces for later set-ups. The representation covers cutting operations and non-cutting operations, such as surface
finishes and coatings. The paper concludes with an example that illustrates the application and power of the scheme. 相似文献
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Badreddine Ayadi Bernard Anselmetti Zoubeir Bouaziz Ali Zghal 《The International Journal of Advanced Manufacturing Technology》2008,39(3-4):279-290
This paper proposes a three-dimensional approach towards manufacturing tolerancing that uses a strategy to strictly consider the definition of a datum system imposed by ISO standards. This approach, called three-dimensional manufacturing tolerancing (TMT), is based on the small displacement torsor, which describes the possible deviations between machined surfaces and nominal surfaces of the part model. Every requirement of the definition drawing is treated separately with its own calculation model. The iterative ascending analysis allows one to establish the influence of the most recent phase and determine the influential parameters from previous phases. The nominal part model is defined on the datum systems of the requirement, and deviations are expressed with respect to both the machining process and the chosen machine adjustment method. The result takes the form of a formula that yields the variation in characteristics specified in the requirement based on quantifiable parameters identified on the machine. 相似文献
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A. Desrochers A. Clément 《The International Journal of Advanced Manufacturing Technology》1994,9(6):352-361
A model called TTRS for technologically and topologically related surfaces, has been developed and its application to dimensioning and tolerancing is presented here. According to this model, any part can be represented as a succession of binary surfaces associations forming a tree. Additionally, each surfaces association, termed as a TTRS object, is represented by a set of minimum geometric datum elements (MGDE). Once established, each TTRS can be given appropriate geometric dimensioning and tolerancing (GD & T) symbols through a general procedure making use of GD & T tables and combination rules. Application examples are also presented. 相似文献
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W. Bouzid Sai W. Dhifalli A. Zghal 《The International Journal of Advanced Manufacturing Technology》2006,31(1-2):71-77
To obtain imposed dimensional and geometrical specifications for any mechanical piece, production tolerances must be calculated. So a simulation of workpiece behavior when it is machined, has permitted calculations of deviations on machined surfaces.The method of deviation calculation is based on a comparison between imposed functional tolerance and the tolerance calculated in relation to deviations on two machined surfaces or between a machined surface and the operational datum.The one direction modelling of deviations inquires practical inputs such as the planning process, the operational datum, the deviations on rough surfaces, and deviations on surface datum for any stage of machining. The developed method allows determining the deviations on machined surfaces. Then, tolerances on production dimensions were calculated in three directions. These results have permitted to define average production dimensions, which may be used for NC machine programming and to prepare an optimal rough piece configuration.The developed method has been applied for the machining of a fixing screw. 相似文献
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薄壁钢结构碰撞性能仿真中材料模型研究 总被引:6,自引:0,他引:6
讨论了动态弹塑性理论中的应变率相关材料本构关系及其在数值计算中的简化模型,研究了计入应变率、不计入应变率的双线性弹塑性材料摸型和3参数Barlat材料模型在闭口帽型薄壁梁在轴向碰撞载荷下的屈曲模态中对数值计算结果的影响,并和实验数据进行了比较,结果显示在碰撞研究中应变率对结构碰撞特性有着重要的影响。仿真结果表明应变率是薄壁钢材料构件静动态实验结果差异的主要因素,并由此给出了应变率影响的敏感性系数。研究结果为利用有限元方法进行碰撞结构设计提供了依据。 相似文献
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As a typical engineering application of basic principle of Bertrand conjugate surfaces, the general principle of normal circular-arc gear transmission, including paralleled-axis, intersected-axis and crossed-axis, is systematically studied. The research method, from datum surface to the directrix, is presented. The types of datum surfaces and the directrixes of all kinds of transmissions and the method to generate tooth flank of normal circular-arc gear are developed, and the investigation on the noninterference condition is performed by the curvature axis. Three typical normal circular-arc gear transmissions as loxodromic-type, geodesic-type and hyperboloidal-type under the condition of intersected-axis and crossed-axis are proposed. 相似文献
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针对电解加工产生的气泡影响加工精度的问题,引入Euler Euler双流体模型对电解加工中气液两相流场进行描述,并耦合电场和温度场相关模型,分析了工具阴极、工件阳极表面气泡率、温度、电导率和电流密度的分布规律;通过调整加工电压、入口压力和出口压力,对工件阳极表面气泡率和电流密度分布进行仿真优化。仿真结果表明:在流速相同的条件下,减小加工电压、增加出口压力能够改善电导率分布,使阳极表面电流密度分布更加均匀。实验结果表明:仿真得到的阳极表面电流密度分布与工件轮廓高度误差分布吻合;采用优化后参数加工出的工件轮廓精度得到提高。 相似文献