DX12000×1000大面铣床设计构想

从经济性、实用性以及加工质量方面对铸铝母线的大面积铣削进行了简要分析 ,设计确定了 DX1 2 0 0 0× 1 0 0 0大面铣床的结构以及技术参数 ,并对其使用效果进行了简介     

AutoCAD中函数曲线命令的编辑与使用

介绍了运用AutoLISP语言 ,采用对话框编程技术调用AutoCAD命令编辑程序 ,并与CAXA电子图板 2 0 0 0做了比较     

关于0-1背包问题的研究

阐述了0-1背包问题的概念,对主要的近似算法及精确算法进行了说明,并比较了它们各自的优点和缺点,在此基础上提出了未来0-1背包算法的发展方向和趋势,并指出用粗糙集理论来解决0-1背包问题的可能性。     

深化企业改革整顿优化行业经济结构加快广西机械工业改革与发展的步伐——在广西机械工业工作会议上的讲话

报告总结了 1 999年广西机械工业取得的成绩和存在的差距 ,分析了 2 0 0 0年广西机械工业面临的形势 ,提出了指导思想和预期目标并部署了主要工作任务。     

KNOF-400成捆器工作原理及改进

该文对KNOF 4 0 0成捆器工作原理进行了介绍 ,并根据实际工作情况对系统进行了改进     

S—N曲线转折点循环数N_0的探讨

转折点循环数N0 是变幅载荷疲劳强度评价的一个至关重要的参数。文中首先对国产机械材料的材料S—N曲线的转折点循环数N0 进行了试验研究 ,分别得出几类钢的N0 中值寿命 ,并将它们作为该类钢的N0 推荐值。然后 ,对不同锐度缺口试样S—N曲线的N0 值与光滑试样S—N曲线的N0 值间的关系进行了研究。结果表明 ,缺口试样S—N曲线的N0 值大体上不随缺口试样的缺口锐度改变 ,且与光滑试样S—N曲线的N0 值相差不大。并由此推论出 ,可以用材料S—N曲线的N0 值和N0 推荐值作为零件S—N曲线的N0 值和N0 推荐值     

基于AutoCAD的成形车刀截形作图设计方法

提出利用AutoCAD 2 0 0 0对成形车刀截形进行作图设计 ,讨论了棱体和圆体成形车刀截形的作图设计原理和方法 ,并举例说明了棱体成形车刀工作图的设计步骤     

刀具图形管理系统的可视化

为了实现图形数字化 ,进而实现图形资源共享 ,本文在Windows2 0 0 0环境下 ,以Solidworks2 0 0 0为图形平台 ,用Vi sualBasic6 .0和Access2 0 0 0为数据库开发工具 ,开发了刀具参数化图形管理系统 ;并在所编刀具可视化图形管理系统的基础上 ,建立了动态的可视化刀具图形管理系统。该系统除了实现各刀具图形及参数的可视化外 ,还可以通过采用对话框形式根据实际情况实现系统的数据库查询和更新的可视化。     

提高孔位置精度的途径

孔的位置精度一般只能较稳定地保证在± 0 0 5～± 0 10 9mm。当位置的精度要求达到± 0 0 2 5～± 0 0 3mm时 ,需进一步采取措施来保证。本文就如何提高孔加工中位置精度这一问题 ,作了初步探讨 ,并结合实例 ,介绍了夹具设计的经验。     

AutoCAD二次开发参数的处理方法

介绍了在机械设计中 ,利用AutoCAD进行二次开发时常见的参数处理方法 ,给出了参数与系统的对象关系图 ,并详细介绍了利用AutoCAD 2 0 0 0的VBA进行二次开发时数表和线图的一种有效处理方法。     

噪声环境下圆度误差分离的统一方法

提出了一种噪声环境下圆度误差分离的统一方法。这种方法利用频域测量矩阵直接给出了圆度形状误差和回转误差的最小二乘解或最小均方误差解。频域测量矩阵的范数反映了噪声对误差分离结果的影响程度。介绍了圆度误差分离中的频域最小范数混合解，这种混合解比最小二乘解和最小均方误差解具有更好的噪声抑制效果。     

Combined analytical and numerical solution for an elastically supported Timoshenko beam to a moving load

A combined analytical and numerical method is presented to get a response for an elastically supported Timoshenko beam to a moving load. The analytical steady-state solution as a particular solution is established and summed with the numerically calculated homogeneous solution. A steady-state solution is sought analytically through the direct application of the Fourier transform to the moving step load. It is shown to be a compact formula composed of exponential and sinusoidal functions depending on the load velocity. The homogeneous solution is established numerically to cancel out the discontinuities and the inconsistent boundary and initial conditions of the steady-state solution. The discontinuities produced by the steady-state solution are removed using the physical characteristics related to the bar wave. Some response curves are shown to compare the beam motions at different load velocities.     

Solving reverse logistics vehicle routing problems with time windows

A vehicle routing problem with simultaneous pick-up and delivery in closed-loop logistics network optimization is studied in this paper. Since, in practice, material pick-up and delivery are only allowed to take place on certain time periods, we consider the reverse logistics vehicle routing problem with time windows. A mixed integer programming model is proposed to formulate the considered problem. A heuristic solution approach for solving the model is developed due to the NP-hard nature of solving the model. The heuristic solution is then used as an initial solution of a simulated annealing procedure for improved solutions. The proposed heuristic method and the simulated annealing procedure yield very promising solutions in much less computational time when compared with optimal solutions generated by exact solution procedures. Numerical examples are presented to illustrate the developed model and solution methods.     

Evaluation method for spatial straightness errors based on minimum zone condition

A nonlinear mathematical model for spatial straightness error evaluation based on the minimum zone condition is established in this paper. According to the error analysis, it is proved that the mathematical model for spatial straightness error evaluation cannot be linearized. A criterion for verification of the existence and uniqueness of the minimum zone solution is proposed. A new computational method is also proposed, and practical examples are given. Finally, the correctness of this method is demonstrated using a geometrical solution. This new method is convenient for computation of uniqueness and exactness of the minimum zone solution.     

带有路面不平度主动悬架控制力的分析与计算

建立了双重阻尼的汽车主动悬架的简化模型,给出了一种动载荷及路面不平条件下汽车主动悬架控制力的解析解及其动载荷的数值解的计算方法.最后通过面向对象的编程给出数值解的计算实例.     

7A04铝合金深冷处理的组织和性能研究

对7A04铝合金试样分别采取普通固溶处理和固溶加深冷处理,并在不同的温度下进行人工时效。结合金相组织,硬度、抗拉强度和冲击韧性的测试值对比两组工艺,分析深冷处理对7A04铝合金时效金相组织和力学性能的影响。结果表明:深冷处理能使7A04铝合金在晶粒内外产生大量析出相,并形成较为均匀的弥散分布。7A04铝合金固溶+深冷处理的理想时效温度为120℃,时效16 h,峰值时效硬度为190 HB,最高抗拉强度为679 MPa,与普通固溶处理相比分别提高了24.1%和26.9%,韧性略有提高,具有较高强韧性。     

厚壁圆筒在内压和轴向力复合载荷作用下的极限载荷

基于理想弹塑性材料假设和Von—Mises屈服准则,考虑厚壁圆筒三向应力分布的不均匀性以及圆筒的几何特性,推导给出了厚壁圆筒在内压和轴向力共同作用下的极限载荷表达式。文中的理论解与前人的解比较结果表明,文中的解比现有解精确,用于薄壁圆筒时,其解与现有的薄壁解一致。     

Nonlinear Dynamic Analysis of Noncontacting Coned-Face Mechanical Seals

The complete nonlinear equations of motion of a flexibly mounted stator in a noncontacting coned-face mechanical seal are solved numerically. The solution utilizes a transient dynamic analysis and takes into account rotor axial runout and assembly tolerances in the form of initial stator misalignment. Cavitation of the fluid film is also accounted for. A parametric investigation is performed and the effect of various design parameters and operation conditions on the seal dynamics is presented and discussed. A critical shaft speed is found above which the seal becomes dynamically unstable. A critical rotor runout is found which, if exceeded, will cause seal failure due to local face rubbing contact. A comparison is made between the numerical results and those of a simpler analytical solution. It is found that the analytical solution is valid for most practical applications of mechanical seals.     

一种可重构制造系统的生产计划方法

虚拟企业是实现敏捷制造的有效途径，是一种可重构的制造系统。系统在重构过程中，各合作伙伴给出完成各自任务的时间段，制造系统则基于这些信息编排出生产计划。本文建立了这一生产计划问题的数学模型，基于该模型，提出了一个有效算法，并给出了一个简单算例。结果表明，所提出的算法可以决定解的存在性，如果解存在，则求出有效解；如果解不存在或解不可以接受，盟主可与合作伙伴协商解决问题。     

Elastic-plastic stresses in a rotating solid disk

A polynomial stress-strain relation is proposed for rotating disks with non-linear strain hardening materials. The basic equation of the disks with constant thickness and constant density under plane stress is derived from the deformation theory of plasticity, Von Mises’ yield criterion and the proposed stress-strain relation. A computing method for such rotating solid disks is developed and the approximate analytical solution is obtained. The validity of the solution is demonstrated by comparing the analytical calculation results with the finite element ones and very good agreement is found. The proposed solution is much more efficient and eassier to use than the FE approach