潜在材料失效分析 安全因子图用于表征可能发生材料失效的区域。 失效准则 可以快速计算不同的失效准则，并动态更新结果。材料失效准则由以下不等式表示： 准则值 < 1 如果符合不平等条件，则认为材料安全。准则值取决于材料在给定位置的应力状态。安全因子与准则值相反。将不等式的两边除以准则值，就能得到通过安全因子表示的失效条件： 安全因子 = 1/准则值 Note: 合适的失效准则取决于材料和应用。它还能够反映被认为适合特定设计的保守程度。虽然为每种 SimSolid 材料提供了默认准则，但它们仅应被视为示例。最终决定使用哪种准则是设计工程师的责任。 SimSolid 中的安全区云图 安全区云图以 3 个彩色条纹（红色、黄色和绿色）表示。条纹之间的阈值由安全因子最低值和安全因子最高值控制。这些因子充当准则值的乘数，并反映您希望容忍的不确定性程度。例如，安全因子值 1.25 表示失效准则值的安全裕度为 25%。 失效理论 失效理论是特定于材料的，它们的公式取决于所考虑的材料类型。 塑性材料 在塑性材料中，失效是通过屈服发生的。塑性材料包括大部分金属和部分塑料。材料的拉伸屈服强度 (TYS) 用于确定工作应力。在屈服之前，假定材料的响应是弹性的。 Figure 1. 许多钢，特别是热处理材料，没有明确的弹性极限。在这种情况下，屈服强度通常定义在塑性应变约为 0.1% 至 0.2% 的点上 CAUTION: 钢通常被认为是一种塑性材料。然而，情况并不总是如此。在 20°至 40°F（-7°至 5°C）的低温下，许多钢开始失去其塑性。低于某一转变温度，就不能再把钢当作塑性材料。 建议您联系材料供应商，了解有关如何确定材料失效的最佳做法。 脆性材料 在脆性材料中，失效是通过断裂发生的，因此失效准则不同于塑性材料。压缩时的断裂应力远大于拉伸时的断裂应力。 Figure 2. SimSolid 中可用的失效理论如下： 最大米塞斯等效应力 该理论最适用于塑性材料，也被称为最大变形能量准则、八面体剪切应力理论或麦克斯韦尔-胡博-亨基-冯-米塞斯理论。它是根据材料的拉伸屈服强度与米塞斯等效应力的比值来计算的，通常认为与实验结果最为吻合。 最大切应力 这一理论最适用于塑性材料，也被称为特雷斯卡准则或盖斯特准则。它指出，当模型中的最大剪切应力等于拉伸测试样本中已开始屈服的最大剪切应力时，屈服就开始了。与最大米塞斯等效应力理论相比，最大剪切应力是一种更为保守的方法。在某些情况下，它可能会将应力高估 15%。 (1) 最大法向应力 该理论最适用于脆性材料，也称为库仑准则。它是通过检验材料的抗拉强度和抗压强度与最大主应力的比值来计算的。 克里斯滕森 这是一种较新的理论，试图弥合塑性材料和脆性材料的失效标准之间的差距。克里斯滕森失效准则由代表竞争性失效机制的两个独立子准则组成。一种是类似于米塞斯准则的二次型，另一种是类似于库仑-莫尔准则的协调断裂准则。 失效准则公式 Table 1. 准则 公式 最大米塞斯等效应力 SF = σ tensile yield σ von Mises MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaae4uaiaabA eacaaMc8UaaeypaiaaykW7daWcaaqaaiaabo8adaWgaaWcbaGaaeiD aiaabwgacaqGUbGaae4CaiaabMgacaqGSbGaaeyzaiaaysW7caqG5b GaaeyAaiaabwgacaqGSbGaaeizaaqabaaakeaacaqGdpWaaSbaaSqa aiaabAhacaqGVbGaaeOBaiaaysW7caqGnbGaaeyAaiaabohacaqGLb Gaae4Caaqabaaaaaaa@5421@ 最大切应力 SF = σ tensile yield 2 τ max MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaae4uaiaabA eacaaMc8UaaeypaiaaykW7daWcaaqaaiaabo8adaWgaaWcbaGaaeiD aiaabwgacaqGUbGaae4CaiaabMgacaqGSbGaaeyzaiaaysW7caqG5b GaaeyAaiaabwgacaqGSbGaaeizaaqabaaakeaacaaIYaGaaGPaVlab es8a0naaBaaaleaaciGGTbGaaiyyaiaacIhaaeqaaaaaaaa@50BF@ 其中： τ max = maximum σ 1 − σ 2 2 , σ 2 − σ 3 2 , σ 3 − σ 1 2 MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaaeiXdmaaBa aaleaacaqGTbGaaeyyaiaabIhaaeqaaOGaaeypaiaaykW7caqGTbGa aeyyaiaabIhacaqGPbGaaeyBaiaabwhacaqGTbGaaGjcVlaaykW7da qadaqaamaaemaabaWaaSaaaeaacqaHdpWCdaWgaaWcbaGaaGymaaqa baGccqGHsislcqaHdpWCdaWgaaWcbaGaaGOmaaqabaaakeaacaaIYa aaaaGaay5bSlaawIa7aiaacYcadaabdaqaamaalaaabaGaeq4Wdm3a aSbaaSqaaiaaikdaaeqaaOGaeyOeI0Iaeq4Wdm3aaSbaaSqaaiaaio daaeqaaaGcbaGaaGOmaaaaaiaawEa7caGLiWoacaGGSaWaaqWaaeaa daWcaaqaaiabeo8aZnaaBaaaleaacaaIZaaabeaakiabgkHiTiabeo 8aZnaaBaaaleaacaaIXaaabeaaaOqaaiaaikdaaaaacaGLhWUaayjc SdaacaGLOaGaayzkaaaaaa@67F4@ 最大法向应力 SF i = σ tensile yield σ i MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaae4uaiaabA eadaWgaaWcbaGaaeyAaaqabaGccaaMc8UaaeypaiaaykW7daWcaaqa aiaabo8adaWgaaWcbaGaaeiDaiaabwgacaqGUbGaae4CaiaabMgaca qGSbGaaeyzaiaaysW7caqG5bGaaeyAaiaabwgacaqGSbGaaeizaaqa baaakeaacaqGdpWaaSbaaSqaaiaabMgaaeqaaaaaaaa@4D36@ 如果 σ i MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaae4WdmaaBa aaleaacaqGPbaabeaaaaa@3854@ > 0 和 SF i = σ compressive yield σ i MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaae4uaiaabA eadaWgaaWcbaGaaeyAaaqabaGccaaMc8UaaeypaiaaykW7daWcaaqa aiaabo8adaWgaaWcbaGaae4yaiaab+gacaqGTbGaaeiCaiaabkhaca qGLbGaae4CaiaabohacaqGPbGaaeODaiaabwgacaaMe8UaaeyEaiaa bMgacaqGLbGaaeiBaiaabsgaaeqaaaGcbaGaae4WdmaaBaaaleaaca qGPbaabeaaaaaaaa@50FE@ 如果 σ i MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaae4WdmaaBa aaleaacaqGPbaabeaaaaa@3854@ < 0 对于 i = 1, 2, 3 SF = minimum SF 1 , SF 2 , SF 3 MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaae4uaiaabA eacaaMc8UaaeypaiaaykW7caqGTbGaaeyAaiaab6gacaqGPbGaaeyB aiaabwhacaqGTbGaaGPaVpaabmaabaGaae4uaiaabAeadaWgaaWcba GaaeymaaqabaGccaqGSaGaaGPaVlaabofacaqGgbWaaSbaaSqaaiaa bkdaaeqaaOGaaeilaiaaykW7caqGtbGaaeOramaaBaaaleaacaqGZa aabeaaaOGaayjkaiaawMcaaaaa@511F@ 克里斯滕森 如果 σ tensile σ compressive ≤ 1 2 MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaeWaaeaada Wcaaqaaiaabo8adaWgaaWcbaGaaeiDaiaabwgacaqGUbGaae4Caiaa bMgacaqGSbGaaeyzaaqabaaakeaacaqGdpWaaSbaaSqaaiaabogaca qGVbGaaeyBaiaabchacaqGYbGaaeyzaiaabohacaqGZbGaaeyAaiaa bAhacaqGLbaabeaaaaGccaaMc8UaeyizIm6aaSaaaeaacaqGXaaaba GaaeOmaaaaaiaawIcacaGLPaaaaaa@501D@ 那么 SF 1 = σ tensile σ 1 , SF 2 = σ tensile σ 2 , SF 3 = σ tensile σ 3 MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaae4uaiaabA eadaWgaaWcbaGaaeymaaqabaGccaaMc8UaaeypaiaaykW7daWcaaqa aiaabo8adaWgaaWcbaGaaeiDaiaabwgacaqGUbGaae4CaiaabMgaca qGSbGaaeyzaaqabaaakeaacaqGdpWaaSbaaSqaaiaabgdaaeqaaaaa kiaabYcacaaMe8Uaae4uaiaabAeadaWgaaWcbaGaaeOmaaqabaGcca aMc8UaaeypaiaaykW7daWcaaqaaiaabo8adaWgaaWcbaGaaeiDaiaa bwgacaqGUbGaae4CaiaabMgacaqGSbGaaeyzaaqabaaakeaacaqGdp WaaSbaaSqaaiaabkdaaeqaaaaakiaabYcacaaMe8Uaae4uaiaabAea daWgaaWcbaGaae4maaqabaGccaaMc8UaaeypaiaaykW7daWcaaqaai aabo8adaWgaaWcbaGaaeiDaiaabwgacaqGUbGaae4CaiaabMgacaqG SbGaaeyzaaqabaaakeaacaqGdpWaaSbaaSqaaiaabodaaeqaaaaaaa a@6C65@ SF 4 = 1 E Q MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaae4uaiaabA eadaWgaaWcbaGaaGinaaqabaGccaaMc8UaaeypaiaaykW7daWcaaqa aiaaigdaaeaadaGcaaqaaiaadweacaWGrbaaleqaaaaaaaa@3EE2@ SF = minimum SF 1 , SF 2 , SF 3 , SF 4 MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaae4uaiaabA eacaaMc8UaaeypaiaaykW7caqGTbGaaeyAaiaab6gacaqGPbGaaeyB aiaabwhacaqGTbGaaGPaVpaabmaabaGaae4uaiaabAeadaWgaaWcba GaaeymaaqabaGccaqGSaGaaGjbVlaabofacaqGgbWaaSbaaSqaaiaa bkdaaeqaaOGaaeilaiaaysW7caqGtbGaaeOramaaBaaaleaacaqGZa aabeaakiaabYcacaaMe8Uaae4uaiaabAeadaWgaaWcbaGaaeinaaqa baaakiaawIcacaGLPaaaaaa@55EB@ 其中： EQ = 1 σ tensile - 1 σ compressive σ 1 +σ 2 +σ 3 + 1 σ yield σ compressive σ von Mises 2 MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaaeyraiaabg facaaMc8UaaeypaiaaykW7daqadaqaamaalaaabaGaaeymaaqaaiaa bo8adaWgaaWcbaGaaeiDaiaabwgacaqGUbGaae4CaiaabMgacaqGSb GaaeyzaaqabaaaaOGaaGjbVlaab2cacaaMe8+aaSaaaeaacaqGXaaa baGaae4WdmaaBaaaleaacaqGJbGaae4Baiaab2gacaqGWbGaaeOCai aabwgacaqGZbGaae4CaiaabMgacaqG2bGaaeyzaaqabaaaaaGccaGL OaGaayzkaaGaaGPaVpaabmaabaGaae4WdmaaBaaaleaacaqGXaaabe aakiaabUcacaqGdpWaaSbaaSqaaiaabkdaaeqaaOGaae4kaiaabo8a daWgaaWcbaGaae4maaqabaaakiaawIcacaGLPaaacaaMc8Uaae4kai aaykW7daqadaqaamaalaaabaGaaeymaaqaaiaabo8adaWgaaWcbaGa aeyEaiaabMgacaqGLbGaaeiBaiaabsgaaeqaaOGaae4WdmaaBaaale aacaqGJbGaae4Baiaab2gacaqGWbGaaeOCaiaabwgacaqGZbGaae4C aiaabMgacaqG2bGaaeyzaaqabaaaaaGccaGLOaGaayzkaaGaaGPaVp aabmaabaGaae4WdmaaBaaaleaacaqG2bGaae4Baiaab6gacaaMe8Ua aeytaiaabMgacaqGZbGaaeyzaiaabohaaeqaaOWaaWbaaSqabeaaca qGYaaaaaGccaGLOaGaayzkaaaaaa@87A2@
