v8_20_spot_sg_msc_format

nullnullMSC/FATIGUE Spot WeldnullMotivation大约50%的汽车结构耐久性问 题 快递公司问题件快递公司问题件货款处理关于圆的周长面积重点题型关于解方程组的题及答案关于南海问题 都与点焊相关About 50% of automotive structural durability problems are associated with spot-welds 大约80%的汽车车身耐久性问题与点焊相关About 80% of automotive body durability problems are associated with spot-welds 在汽车生产线上增加一个点焊设备的成本将近3万美元The tooling cost for 1 spot weld on an automated production line is about $30,000 后期的增加其费用将近2倍Late additions may cost twice this amount 除结构方面的重要性之外，点焊的耐久性问题也是影响产品感官质量的重要因数Besides any structural importance, the durability of spot welds can have an important effect on perceived qualitynullCurrent Practice汽车工业承受着缩短开发时间的持续压力，更少的样机意味着更多的CAEThere is increasing pressure in the automotive industry to reduce development times. Less prototypes means more CAE. 对于点焊，没有一种普遍使用的工具来预测其寿命There are no commonly available tools for life prediction of spot-welds 点焊的数量、位置和大小常由如下： 需焊接板的应力和工程师的工程 经验 班主任工作经验交流宣传工作经验交流材料优秀班主任经验交流小学课改经验典型材料房地产总经理管理经验 点焊布置的可能性和经济性 Spot-weld numbers, positions and sizes are typically decided by: The component engineer, based on panel stresses (spot-welds are often not modelled at all) and experience The production engineer, based on what is possible / economicalnullMSC/FATIGUE Spot Weld是MSC/FATIGUE软件包的可选模块之一，它基于MSC/NASTRAN的有限元 分析 定性数据统计分析pdf销售业绩分析模板建筑结构震害分析销售进度分析表京东商城竞争战略分析 ，可预测两块金属板在点焊连接处的疲劳寿命。计算中将结构的点焊看作是连接两块金属板的刚性杆，而金属板用薄壳单元描述。该方法利用杆单元横截面所受的力和力矩来计算焊接处的应力，然后采用S-N方法，完成结构的全寿命疲劳分析。 null基于结构应力Structural Stress Based Method仅需要较粗的网格，用刚性梁单元模拟点焊Coarse mesh only required, with spot welds modeled as stiff beam elements 梁单元用来作为“力传递器”，用它取得点焊传递的力和力矩Beams are used as " force transducers " to obtain forces and moments transmitted through the spot welds 力和力矩用来进行结构应力计算Forces and moments are used to calculate " structural stresses " 使用Miner法则进行寿命计算Life is calculated using Miner's rule 具有通用性并可处理多轴载荷Method is generally applicable and handles multiaxial loadingsBeam Element( Rupp - Storzel - Grubisic )null FE Model of Strut TowernullHow do we Model Spotwelds?The 5 Box TrickOptimization & TestingLoading (Time History)Material (Weld S-N Data)Geometry (Beam Elements)Fatigue Analysis (Spot Weld Analyzer)Post ProcessingnullLoading History on DampernullStructural Stress Calculations结构应力的计算基于每个梁单元上的力和力矩The structural stresses are calculated from the forces and moments on each beam element :Sheet 2NuggetSheet 1FzMxFxFyMyMyFyFxMxFzFzMxFxFyMy结构应力法在连接板的薄壳单元之间通过刚性梁单元传递力和力矩。根据分析所得的力、力矩，以及点焊的几何模型数据，即可计算出连接板和焊核的应力分布。nullStructural Stress CalculationsE.G. stresses in sheet :焊核应力计算方法类似Similar equations for stresses in nugget 对尺寸效应将进行修正Corrections made for size effectFzMxMyFyFxsdnullFatigue Properties - Typical Test SpecimennullFatigue Properties - Generic S-N Curvesnull损伤计算流程Damage Calculation ProcedureStresses and fatigue damage are calculated at 10 intervals around the spot weld for the 2 sheets and the nugget Stress histories are calculated from : where k = static loadcase i.d., or from transient F.E. Life is calculated using Linear Damage Summation (Miner's Rule)nullResults Postprocessing OptionsListing the results files, life, damage, crack location etc... Plotting in PATRAN / FATIGUE (Insight) Polar plotting of damage " What if ? " games ...nullFatigue Results for Shock TowernullPolar Plot of DamagenullExample Problem:A Spot Weld AnalysisPerform spot weld analysis. Multiple loading inputs at shock tower.nullSolution Parameters SetupnullMaterial Info SetupnullLoading Info SetupnullDisplay Resultsnull虚拟应变片测量 MSC/FATIGUE Software Strain gaugeMSC/FATIGUE 环境下的虚拟测试系统A virtual test facility in the MSC/FATIGUE environmentnullSoftware Strain GaugeA Finite Element tool allowing the creation of Stress and Strain time histories at arbitrary locations on a Finite Element Model Surface Uses: Finite Element Model Results Verification Comparison of Strain Values with Test Time Histories Previous FEA techniques have only permitted comparison of single Stress or Strain values. MSC/FATIGUE Strain Gauge是MSC/FATIGUE系列产品之一。使用Strain Gauge，可在MSC/NASTRAN有限元模型中创建软件形式的虚拟应变片，从而得出有限元模型在随时间变化的多种载荷作用下所产生的响应时间历程的理论结果。根据 标准 excel标准偏差excel标准偏差函数exl标准差函数国标检验抽样标准表免费下载红头文件格式标准下载 的或用户自定义的应变片，可以获得有限元模型上任意一点应力和应变的响应时间历程。从虚拟应变片上可以获得静态、瞬态，或准静态有限元加载过程的仿真结果. nullDescription虚拟应变片创建在有限元模型中，从而得出有限元模型在随时间变化的多种载荷作用下所产生的响应时间历程的理论结果A virtual strain gauge on a finite element model. This gauge can produce theoretical result time histories from multiple time varying applied loads 可以获得有限元模型上任意一点应力和应变的响应时间历程Time histories may be extracted at any point on the mesh surface 结果基于标准或用户自定义的应变片Results based on either standard or user defined strain gauge definitions. 从虚拟应变片上可以获得静态、瞬态，或准静态有限元加载过程的仿真结果The results from static, transient or quasi static finite element loading.null相关性的应用Correlation Applications I通过Strain Gauge，可使工程分析人员把试验采集的数据结果与有限元结构分析的数据结果融合在一起进行相关性比较。 Allows correlation between theoretical calculations with experimentally determined results. 从而增强其依据真实结构所建立的有限元模型的可信度 Permits greater confidence in the finite element model of the real world structure. 应力/应变结果可以用于： 循环计数 功率谱密度函数 损伤/寿命分析Stress / Strain results may be subsequently analysed as: Cycle Counts PSD results Damage / Life Values1000-6005000Strain (uE)Time (Secs)DISPLAY OF SIGNAL: SAETRN.DAC17081 points.9 pts/SecsDisplayed: 4501 points.from pt 1Full file data: Max = 999at 0 Min = -495at 1743 Mean = 385.3S.D. = 235RMS = 451.301508.9-495999016RangeuEX-AxisMeanuEY-AxisCyclesZ-AxisCYCLE HISTOGRAM DISTRIBUTION FOR : SAETRN.CYOMaximum height : 16Z Units : nullCorrelation Applications IIReal World StructureFEA Model SurfaceSoftware Strain GaugesnullWelded Structure Analysis I 使用虚拟应变片测量，有利于分析人员按照英国标准7608进行MSC/FATIGUE焊接寿命计算。The Software Strain Gauge is also of benefit to the analyst performing MSC/FATIGUE weld durability calculations in accordance with British Standard 7608. 计算焊接结构的疲劳寿命时，载荷方向很重要When calculating fatigue life for welded structures the loading direction is of importance 应变片测量技术可在雨流循环计数之前预先给出焊接处某特定方向的应变时间历程，从而为焊接寿命分析提供重要信息。 The strain gauge allows extraction of time histories prior to Rainflow cycle counting in specific directions on an FEA structurenullWelded Structure Analysis I应变片测量技术可预先给出焊接处的应变时间历程，从而为焊接寿命分析提供重要信息 The Gauge tool allows access to strain time histories at the weld toe, providing important information for weld durability calculations.CLASS F WELD DETAIL (BS7608)Real World StructureFEA ModelSoftware Strain GaugesnullGauge Definition 虚拟应变片测量可看成有限元模型中的组（Group）,每一组包含1-3个单元 The gauges are defined as FEA groups, each containing between 1 to 3 elements. 标准应变片的定义Standard gauge definitions: 单轴应变片 Uni-axial Gauges T形应变片T Gauges 三角形应变片Delta Gauges 矩形应变片Rectangular Gauges 平面和叠层应变片Planar and stacked formulations. 用户自定义的测量应变片User defined gauges may also be created 自定义的测量应变片也可由应变片定义文件生成. definitions stored in a gauge definition file. nullImplementation虚拟应变片的位置Gauge position: 有限元模型 表 关于同志近三年现实表现材料材料类招标技术评分表图表与交易pdf视力表打印pdf用图表说话 pdf 面的任何位置Anywhere on the FEA model surface 任意方向Any orientation 可以覆盖多个单元Covering multiple finite elements. Gauge results: Averaged results from the underlying finite elements Replicates the geometric averaging with actual instrumentation. Transformed to the coordinate system and alignment of the software strain gauge. 可同时使用高达200种的虚拟应变片 Up to 200 simultaneous Software Strain GaugesnullExample Problem: A Software Strain GageIntroduce software strain gage as a correlation tool on a mounting lug. Multiple loading inputs.nullSoftware Strain Gage SetupDefine node to initially put gage on ...and elements that define surfacenullLoading Info SetupnullPerform AnalysisDefine material and loading Extract time histories from rosette Perform rosette analysis and correlationnullCorrelation TechniquesOverlays and cross plots Rosette analysis Single location uniaxial life analyzer Single location multiaxial life analyzernullExercise Perform Quickstart Guide Chapter 13 Exercise, “A Spot Weld Analysis” Perform Quickstart Guide Chapter 14 Exercise, “A Software Strain Gauge” Be sure to ask for help if there’s anything you don’t understand