相当応力振幅

相当応力振幅(EQSTSAMP)の概要。

S-N疲労解析では、相当応力振幅( S e q MathType@MTEF@5@5@+= feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4uamaaBa aaleaacaWGLbGaamyCaaqabaaaaa@38D8@ )は、調整された応力-寿命曲線で報告されている寿命( N f MathType@MTEF@5@5@+= feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOtamaaBa aaleaacaWGMbaabeaaaaa@37DE@ )に対応する応力振幅です:

S e q = S R I 1 N f b MathType@MTEF@5@5@+= feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4uamaaBa aaleaacaWGLbGaamyCaaqabaGccqGH9aqpcaWGtbGaamOuaiaadMea caaIXaWaaeWaaeaacaWGobWaaSbaaSqaaiaadAgaaeqaaaGccaGLOa GaayzkaaWaaWbaaSqabeaacaWGIbaaaaaa@41B1@

E-N疲労解析では、調整されたひずみ-寿命曲線から相当ひずみ振幅が最初に取得されます:

ε e q = S f ' E 2 N f b + ε f ' 2 N f c MathType@MTEF@5@5@+= feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqyTdu2aaS baaSqaaiaadwgacaWGXbaabeaakiabg2da9maalaaabaGaam4uamaa DaaaleaacaWGMbaabaGaai4jaaaaaOqaaiaadweaaaWaaeWaaeaaca aIYaGaamOtamaaBaaaleaacaWGMbaabeaaaOGaayjkaiaawMcaamaa CaaaleqabaGaamOyaaaakiabgUcaRiabew7aLnaaDaaaleaacaWGMb aabaGaai4jaaaakmaabmaabaGaaGOmaiaad6eadaWgaaWcbaGaamOz aaqabaaakiaawIcacaGLPaaadaahaaWcbeqaaiaadogaaaaaaa@4D31@

対応する弾塑性応力振幅は、弾塑性応力振幅( σ e q MathType@MTEF@5@5@+= feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeq4Wdm3aaS baaSqaaiaadwgacaWGXbaabeaaaaa@39C3@ )の次の式を解くことによって得られます:

ε e q = σ e q E + σ e q K ' 1 n ' MathType@MTEF@5@5@+= feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaeqyTdu2aaS baaSqaaiaadwgacaWGXbaabeaakiabg2da9maalaaabaGaeq4Wdm3a aSbaaSqaaiaadwgacaWGXbaabeaaaOqaaiaadweaaaGaey4kaSYaae WaaeaadaWcaaqaaiabeo8aZnaaBaaaleaacaWGLbGaamyCaaqabaaa keaacaWGlbGaai4jaaaaaiaawIcacaGLPaaadaahaaWcbeqaamaali aabaGaaGymaaqaaiaad6gacaGGNaaaaaaaaaa@49D1@

最後に、Neuber補正によって、弾性相当応力振幅が得られます:

S e q = E σ e q ε e q MathType@MTEF@5@5@+= feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaam4uamaaBa aaleaacaWGLbGaamyCaaqabaGccqGH9aqpdaGcaaqaaiaadweacqaH dpWCdaWgaaWcbaGaamyzaiaadghaaeqaaOGaeqyTdu2aaSbaaSqaai aadwgacaWGXbaabeaaaeqaaaaa@424E@

出力リクエスト

EQSTSAMP = SET IDにより、サポートされているフォーマットで相当応力振幅結果が得られます。多軸疲労解析を行う場合、臨界面角度も出力ファイルに記載されます。この角度は、平面応力が計算された平面の局所X軸から測定されます。