新型刀杆式切削测力仪

为提供机械加工自动化中切削状态监视技术急需的力传感器,研制开发了新型刀杆式切削测力仪。理论分析与实测结果表明,该测力仪同时具有很高的刚度和灵敏度,并且有安装方便、不影响机床原有特性的特点。     

Design, Construction and Calibration of a Triaxial Dynamometer for Measuring Forces and Moments Applied on Tillage Implements in Field Conditions

In this research, a dynamometer was designed, constructed and calibrated to measure the forces and moments applied on tillage implements. This dynamometer is able to measure the three orthogonal forces acting on the implement and the three moments acting around the orthogonal axes, up to a maximum force of 20 kN and a maximum moment of 20 kN m. The dynamometer uses two extended octagonal ring transducers mounted in a back-to-back arrangement with their axes at right angles and has a tubular torque meter for torque measurement. For mechanical design of the dynamometer frame and its units, the finite element method and CATIA software were used. The device was machined from the solid part and high tensile steel. The forces and moments acting on the dynamometer were measured by using the strain gauge bridges on two extended octagonal ring transducers and on the torque meter tube. The results of data analysis, including forces applied on the dynamometer, the designing method of rings and torque meter tubes, the mounting arrangement of load cell parts on each other, the mounting method of load cell on frame and the position of strain gauge on load cell, in other words, the position of different parts of the dynamometer relative to each other has been explained in this paper. Calibration of the measurement unit was done by a calibration system which was designed for static calibration of the triaxial dynamometer. The results of calibration of the measurement unit showed that the designed and constructed dynamometer has appropriate precision, sensitivity and good repeatability for measuring the desired forces and moments. The results showed a high degree of linearity between output voltage of bridges and applied forces and moments. The interaction effects of the applied forces and moments were very negligible.     

Design, development and testing of a turning dynamometer for cutting force measurement

In this study, a turning dynamometer that can measure static and dynamic cutting forces by using strain gauge and piezo-electric accelerometer, respectively, has been designed and developed. The orientation of octagonal rings and strain gauge locations has been determined to maximize sensitivity and to minimize cross-sensitivity. The developed dynamometer is connected to a data acquisition system. Cutting force signals were captured and transformed into numerical form and processed using a data acquisition system consisting of necessary hardware and software running on MS-Windows based personal computer. The obtained results of machining tests performed at different cutting parameters showed that the dynamometer could be used reliably to measure cutting forces. Although the dynamometer was developed primarily for turning operations, it can be used to measure cutting forces during nearly all machining operations (milling, drilling, etc.).     

An application of goal programming technique in metal cutting

This paper outlines the use of the goal programming technique in selecting levels of machining parameters in a fine turning operation on A1S1 4140 steel using cemented tungsten carbide tools. Goals that are proposed to be achieved are: (i) to finish turning the required depth in one pass, mid (ii) to finish turning within a stipulated time. Constraints used are: R.M.S. surface finish values, cutting horse power of the machine, ranges for cutting speed, feed and depth of cut. A predictive equation to predict the R.M.S. Surface roughness values from the machining variables, cutting speed, feed, depth of cut, and time of cut was used. This mathematical model was developed using stepwise regression analysis on the experimental data for 1/64 in. nose radius cemented tungsten carbide cutting tool. Experiment with the machining variables at different levels were performed to obtain the data. A statistically designed experiment called the rotatable design was used for the experimental design     

基于八角行为分析的服务设计策略研究

目的 尝试将用户行为作为服务设计研究目标,将八角行为分析法引入服务设计,为服务设计及用户研究工作提供创新思路及指导策略。方法 基于八角行为分析法、用户体验及服务设计理论,结合文献调研,构建适用于服务设计的SD-八角模型,提出基于八角行为分析的“二维五步”设计迭代策略。结果 以健身机构为例,从宏观及微观的双重视角,对静态服务系统及动态用户行为进行“二维约束”。结合以SD-八角模型为中心的“五步迭代”策略,将用户体验历程按照用户类型及体验时间展开进行分析,完成立体化、多层级的用户行为分析。结论 将游戏思维融入服务设计,辅助设计者更为精准、全面地进行用户研究,从而发现具有不同可行性的设计机会点,为服务策略提供有效的信息。     

线型聚能切割器结构参数优化设计及应用

针对钢结构目标,优化设计了一种组合式的爆炸切割装置,此装置可以实现对钢结构目标的快速高效切割。以线型聚能装药为研究对象,采用正交优化设计方法,对线型聚能切割器的药型罩壁厚、顶角、口径、炸高等主要结构参数进行优化设计,并确定了最优线型聚能装药结构。采用该结构参数的线型聚能切割器,能够对典型钢结构目标进行有效切割。     

以形状文法为导向的参数化传统纹样设计技术研究

目的 将现代参数化生成技术融入传统纹样设计方法,以此弥补传统的纹样设计方法对设计结果可控性低、产出效率低的不足,从而探索传统纹样创新设计的新途径。方法 运用模件系统理论和图谱量化法提取传统纹样的文化基因图案,采用Grasshopper参数化工具重构纹样,并将形状文法推演规则转译为参数化语法表达的形状文法推演规则,运用系统的文法规则控制感性随意的纹样参数衍生流程,实现基于形状文法导向的参数化纹样设计方法。结果 以黄梅挑花八角莲纹为例,编写形状文法控制的纹样衍生参数化程序,生成多种八角莲纹衍生图案,并应用于不同的文创载体。结论 参数化设计逻辑下的形状文法可以更高效地挖掘传统文化纹样的创新设计价值,以形状文法为导向的参数化技术可灵活并科学地对传统纹样进行再设计,为数字化时代下非物质文化遗产的保护和传承提供参考。     

阻性环式消声器系列产品结构型式与设计特点

本文以GJH型阻性环式消声器系列的结构型式和设计特点,就阻性环式消声器扭作片式消声器通道截面由矩形向圆环形的变表,可通过不断增加吸声环数来适用风机各种风量大小的消声,并具有更好的流体状态和外形刚性、组装和运输更方便的特点。     

Robust product development for multiple quality characteristics using computer experiments and an optimization technique

Conventional parameter or tolerance designs focus on developing exact methods to minimize quality loss or manufacturing cost. The inherent assumption is that the response functions which represent the link between controllable variables and response values of quality characteristics are known before a design is developed. Moreover, parameter and tolerance values are assumed to be independent controllable variables in previous works; namely, they are determined separately in design activities. Currently, advanced computer software, such as computer-aided engineering, can help engineers to handle design problems with unknown response functions, at the stage of product design and process planning. Therefore, in this study, the software ANSYS was employed to obtain simulation data which represent the response values of quality characteristics. These response values will be used to fit a set of response functions for later analysis. However, previous works in computer simulation for design and planning usually lack consideration of the noise impact from an external design system. To approximate a realistic design environment, various levels of controllable variables, in conjunction with artificial noises created from uncontrollable variables, are used to generate simulated data for statistical analysis via Response Surface Methodology (RSM). Then, an optimization technique, such as mathematical programming, is adopted to integrate these response functions into one formulation so that optimal parameter and tolerance values are concurrently determined, with multiple quality characteristics taken into consideration. A bike-frame design was used to demonstrate the presented approach, followed by multiple quality characteristics of interest: material cost, bike-frame weight, structure reliability, and rigidity dependability. The goal is to minimize material cost and bike frame weight and to maximize structure reliability and rigidity dependability. This approach is useful for solving any complex design problems in the early stages, while providing enhanced functionality, quality, economic benefits, and a shorter design cycle.     

径-轴双向环轧工艺的研究进展

回顾了环件径-轴双向轧制锻透条件、咬入条件、刚度条件等相关理论研究进展,分析了工艺参数对轧制过程的影响及其确定准则,在此基础上引入轧制曲线的概念,并给出了径-轴双向环轧轧制曲线的设计原则,还探讨了在利用有限元方法模拟轧制过程、优化轧制工艺参数时存在的问题,并给出了对数值模型进行控制和处理的有效方法。     

统计能量法和导纳功率流对单层隔振系统研究的对比

将单层隔振系统的基础和机器作为柔性体研究其隔振效果,采用统计能量法和导纳功率流法两种分析方法研究对比都得到减小隔振器刚度和阻尼、增大机器阻尼、提高机器和基础刚度有利于减小传递功率流的结论,和增大板基础刚度比增大机器刚度更能减小传递功率流的结论,表明两种功率流分析法的统一性,而统计能量法更加简洁.     

高精度目标跟踪系统地基环的力学分析

对高精度目标跟踪系统及地基环建立了结构分析模型,采用I-DEAS软件对地基环作了静 力分析,求出了系统前五阶固有频率和振型。从理论上对各振型进行了分析,分析结果表明,整个系统具有较高的固有频率,有较强的抗振性,地基环的强度和刚度能够满足要求,从而为实际工程提供了设计依据。     

Experimental Analysis of Cutting Forces in Microdrilling of Austenitic Stainless Steel (X5CrNi18-10)

This article presents an experimental investigation on microdrilling of austenitic stainless steel which is a difficult material for machining because of its properties like high strain-hardening rate, low thermal conductivity, and high fracture toughness. Microholes are produced on X5CrNi18-10 austenitic stainless steel workpiece using 0.5 mm diameter solid carbide microdrills. Two factors (cutting speed and feed) and three levels (low–center–high) full-factorial design of experiment are performed. Response surface methodology is used to developed mathematical models (quadratic and bilinear regression models) for cutting forces in microdrilling. The experimental analysis shows that feed affects the cutting force components (radial and thrust) significantly. Additionally, it also shows that there are only minor effects from cutting speed, square of cutting speed, square of feed and product of speed, and feed on the cutting forces. Finally, the optimized cutting conditions are proposed for minimum cutting forces.     

Dynamic Simulation and Optimization Design of the Pendulum Ring Mechanism Based on ADAMS

For pendulum ring mechanism, the working principle is analyzed by using the ADAMS software. Confirming the simulation to accord with the actual motion law, the main bars＇ length is taken as the design variables in order to optimize the cutting speed. The optimization results show that the length of the pendulum rod increases by 3.22%, the cutting speed increases by 30. 8%. It shows that the length of pendulum rod determines the cutting speed at a given pendulum angle. Designers can adjust the length of pendulum rod so as to select the appropriate cutting speed. The virtual prototype technology could the performance of the product is not only improved, and the design efficiency is also done.     

焊接双活塞环定位片工装的虚拟设计

置于发动机汽缸内的双活塞环,是一种可以提高发动机效率的新型节能装置,其设计思想简练、结构简单可靠.焊接活塞环上的定位片是保证该技术的重要工序,焊接工装设计是实现节能目标的关键.在工装设计中,应用计算机辅助设计手段,成功地实现了焊接工装的结构设计、装配、干涉检查和运动仿真、由三维模型向二维工程图的转换等工作.设计直观形象,准确可靠,提高了设计效率,降低了生产成本.     

盘形滚刀垂向振动特性分析与试验

盘形滚刀的垂向振动对于全断面隧道掘进机的贯入度和破岩效率有一定的影响,为了研究影响滚刀垂向振动的因素,首先建立盘形滚刀垂向三自由度振动模型,得到盘形滚刀刀圈与刀体、圆锥滚子轴承和刀轴的等效质量和刚度,利用MATLAB软件对该振动模型进行仿真,得到滚刀各部分的振动位移,并通过试验得到滚刀各部分振动位移与仿真的结果趋势一致。结果表明:滚刀的刀圈加刀体的最大振动位移量为2.8×10^-4 m,轴承最大振动位移为2.1×10^-4 m,当滚刀的轴承刚度增大3倍时,各部分最大振动位移减少约50%,增大刀圈刀体刚度时,各部分最大振动位移减少约12%,盘形滚刀减振需要增加轴承和刀圈刀体的刚度。研究结果为盘形滚刀的振动测量提供了一种有效方法,对滚刀的设计具有重要的指导意义。     

Development of a high rigidity superconducting magnet for the Maglev system

A high rigidity type superconducting magnet (SCM) is developed and tested by an electromagnetic vibration simulator which simulates the actual running conditions. To reduce the increase in heat load due to the vibration of the cryostat, several kinds of design concepts are chosen. It is recognized from the experiment result that the most effective design concept is to increase the characteristic frequency in twisting mode of the inner vessel with the high rigidity outer vessel.     

竹林皆伐机路径规划系统设计及计算机仿真

目的设计一种中幼竹林皆伐机路径智能规划系统,实现伐竹机伐竹的路径规划功能,使伐竹机可以遍历需要伐竹的全部节点并避开障碍。方法针对中幼竹林皆伐的特点,探讨一种迪杰斯特拉及A*混合算法,用于解决伐竹机路径规划中的路径优化问题。通过C语言编程,来建立一种基于改进的迪杰斯特拉及A*混合算法的中幼竹林皆伐机路径智能规划系统仿模型,并使用C++编程,实现系统模型的仿真,并调用Windows GDI实现仿真结果的显示。结果仿真结果显示,采用文中建立的中幼竹林皆伐机路径规划系统进行伐竹机的路径规划,实现了伐竹路径规划的目标,且相较直接采伐的路径,伐竹机伐竹总里程降低了47.6%,节省了伐竹机伐竹总里程,大大提升了伐竹效率。结论文中所讨论的改进的迪杰斯特拉及A*混合算法可以实现伐竹路径规划的功能,路径规划系统可以求得最优伐竹路径的一个近似解。     

Prediction of cutting force based on machining parameters on AL7075-T6 aluminum alloy by response surface methodology in end milling

Cutting forces modeling is the basic to understand the cutting process, which should be kept in minimum to reduce tool deflection, vibration, tool wear and optimize the process parameters in order to obtain a high quality product within minimum machining time. In this paper a statistical model has been developed to predict cutting force in terms of geometrical parameters such as rake angle, nose radius of cutting tool and machining parameters such as cutting speed, cutting feed and axial depth of cut. Response surface methodology experimental design was employed for conducting experiments. The work piece material is Aluminum (Al 7075-T6) and the tool used is high speed steel end mill cutter with different tool geometry. The cutting forces are measured using three axis milling tool dynamometer. The second order mathematical model in terms of machining parameters is developed for predicting cutting forces. The adequacy of the model is checked by employing ANOVA. The direct effect of the process parameter with cutting forces are analyzed, which helps to select process parameter in order to keep cutting forces minimum, which ensures the stability of end milling process. The study observed that feed rate has the highest statistical and physical influence on cutting force.     

高钢级大口径焊管残余应力的测试方法

针对X80钢大口径UOE,JCOE和SAWH(螺旋缝埋弧焊)三种焊管,研究了盲孔法、切块法和切环法在高钢级大口径焊管残余应力测试中的应用.结果表明:对于这三种管型,通过切环法估算的残余应力与盲孔法和切块法的测试值较为接近,三种方法的结果重合性较好.