Study on virtual animation technology of sheet metal bending

板料折弯成形是指把薄板材料弯成一定角度的加工方法。本文通过分析折弯机结构参数,基于OPEngl ES在WInCE的平台上建立了数控折弯成形仿真的可视化界面,实现了板料折弯成形的3d动态仿真。以树状结构为基础,结合干涉检测等影响板料折弯成形的工艺因素,探讨了板料折弯成形的工艺改进以及工序搜索方法,计算判断出可行的板料折弯成形工序,再由OPEngl ES直观显示板料折弯加工工艺信息。板料折弯成形试验表明,该方法可以实现快速、精确的板料折弯成形。Sheet metal bending is a method to bend the sheet metal with a certain angle.Through analysis of the structural parameters of bending machine and based on OpenGL ES,the visual interface of NC bending animation was established on the WinCE platform,and the3D dynamic animation of sheet metal bending was achieved.Based on tree structure,the forming process development and search method of sheet metal bending were discussed combinated with interference detection and some else factors affecting the forming process.And a feasible procedure of sheet metal bending was achieved,then the information of sheet metal bending procedure was showed with OpenGL ES.And the forming method of sheet metal bending can achieve accurate,rapid and precise sheet metal forming with field machining

腰椎相关结构的退变规律

目的研究腰椎退变患者腰椎骨质、椎间盘、韧带、椎小关节退变及腰椎退变性失稳与年龄、性别的相关性,探讨腰椎退变规律。资料与方法对1180例腰椎退变患者的腰椎CT进行分析,观察不同年龄段、不同性别间椎体骨质、椎间盘、椎小关节、韧带退变以及退变性腰椎失稳的发生率。结果腰椎退变患者腰椎间盘的退变率最高,其次是腰椎骨质、椎小关节、韧带、腰椎失稳。以36岁为年龄分界,36岁以下为腰椎低退变率年龄,以上是腰椎高退变率年龄,不同结构伴随年龄增长的退变率并不是同步递增的,腰椎骨质、椎小关节、韧带退变率及腰椎失稳发生率最高在65岁以上年龄段,而腰椎间盘退变率最高在36~45岁年龄段。男性腰椎间盘、骨质的退变率明显高于女性;椎小关节、韧带的退变率在男、女性间无显著差异;而女性腰椎失稳率明显高于男性。结论总体上伴随年龄增长的腰椎退变,其不同结构的退变规律不一,在不同年龄段及性别间都存在明显差异,全面分析腰椎退变的影像表现有利于对腰椎退变性疾病的理解和治疗

Research on planar spiral wire forming technology

金属线材成形零件种类繁多,其加工成形受到几何参数变化、材料特性等不同因素影响,致使加工精度难以准确控制。针对平面螺旋线材零件的圆弧半径变化现象提出了一种基于迭代思想的误差修正方法。通过分析加工对象的几何特性,建立了线材成形半径、弯曲角度以及线材送料长度三者之间的几何关系模型,建立了加工时送料轴与推弯轴的函数关系;以等半径线材圆弧零件的成形工艺为例,提出了平面螺旋线材的半径误差修正方法,并进行了试验加工,该方法能够有效提高线材加工精度。Forming parts of metallic wire are widely used,but its machining accuracy is difficult to be controlled because of the comprehensive influence of geometric parameters,material properties and other factors.For this phenomenon,an error correction method based on iterative mechanism was proposed by changing the radius of the planar spiral wire parts.Firstly,the geometric relationship among the wire forming radius,cumulative bending angle and wire feed length was derived by analyzing the geometric characteristics of the object to be processed.And then,the formula between the feed axis and the push bending axis was constructed.Finally,the radius error correction model of planar spiral wire was established and applied to the forming process of wire parts with equal radius.The machining result shows that the proposed method could improve the accuracy of wire processing effectively.国家科学技术部支撑项目(SQ2009GJC4001675

Generation and application of NC code for spiral wire

针对螺旋类线材的推弯成形,提出了一种数控代码自动生成方法,并以曲线模型相对复杂的等节距圆锥螺旋弹簧为例进行着重阐述。该方法通过提取线材几何建模参数,并结合推弯模具的结构尺寸和运动形式,建立线材推弯成形的数学模型,推导出送料轴、推弯轴和转臂轴三轴间的联动关系,最后采用等间距直线逼近法生成线材零件的数控加工代码并进行加工生产。试验证明,该方法编程效率高,修改方便,且加工零件可以满足精度要求。A way of automatically generating NC code for the push bending of spiral wire was introduced,and the equal-pitch conoid helical-coil spring whose curve model is relatively complex was emphatically discussed.Through extracting wire parameters of geometric modeling,and combining with the structure size and movement of push bending dies,the mathematical model of the push bending of spiral wire was made,and the linkage relationship among the feed axis,the push bending axis and the rotational axis was derived.Finally NC code was generated by equidistant linear approximation and the processing production was done.The experiment result shows that the programming efficiency of this method is high,the modification is easy,and the parts produced can meet the requirement of accuracy.国家科学技术部支撑项目(SQ2009GJC4001675

手动挡变速器换挡性能测试系统开发与试验研究

对手动挡变速器静态换挡性能和动态换挡性能影响因素进行了分析。基于变速器换挡性能测试需求,设计开发了换挡性能试验台的机械系统和软件系统。基于所开发的试验台架,对某款变速器进行了静态换挡性能和动态换挡性能试验。静态换挡试验表明,所设计开发的测试系统能够准确测量变速器换挡机构的换挡轨迹、挡位间隙以及选挡刚度等性能参数。动态换挡性能试验表明,所设计的试验台能够实时测量换挡力、换挡位移以及变速器输入端转速等性能参数,能够检测出换挡过程中是否发生二次冲击

壁面催化效应对高超声速气动热影响研究

高超声速飞行器壁面催化效应会导致激波层中原子在壁面处复合释热,加剧周围气动热环境。针对高超声速流动壁面催化特性,选择不同飞行马赫数及高度条件,采用完全催化和非催化两种条件对球锥模型壁面热流率进行数值模拟计算,研究壁面催化效应对气动热的影响规律。结果表明,固定飞行高度时,壁面催化效应对气动热的影响随马赫数增加而加强,Ma=25条件下驻点处完全催化与非催化热流比值高达1.92;固定飞行马赫数时,在50km高空以上壁面催化效应对气动热的影响随高度增加而减弱;壁面催化效应不仅会影响壁面附近的流场特性及组分分布状态,而且对整个激波层都有一定的影响作用