/FAIL/JOHNSON

金属の延性破壊の記述には、Johnson-Cook破壊モデルがよく使用されます。これは、Johnson-Cook方程式を用いて破壊ひずみを応力軸性の関数として定義します。

Johnson-Cook破壊モデルには、破壊モデルへの3つのパートがあります;(1)
ε f = [ D 1 + D 2 exp ( D 3 σ * ) ] I n f l u e n c e o f t r i a x i a l i t y [ 1 + D 4 ln ( ε ˙ * ) ] I n f l u e n c e o f s t r a i n r a t e [ 1 + D 5 T * ] I n f l u e n c e o f t e m p e r a t u r e MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVeea0le9v8qqaqFD0xXdHaVhbvc9v8qqaqFr0xb9pg 0xb9qqaqFn0dXdHiVcFbIOFHK8Feea0dXdar=Jb9hs0dXdHuk9fr=x fr=xfrpeWZqaaeaabiGaciaacaqabeaadaqaaqaaaOqaaiabew7aLn aaBaaaleaacaWGMbaabeaakiabg2da9maayaaabaWaamWaaeaacaWG ebWaaSbaaSqaaiaaigdaaeqaaOGaey4kaSIaamiramaaBaaaleaaca aIYaaabeaakiGacwgacaGG4bGaaiiCamaabmaabaGaamiramaaBaaa leaacaaIZaaabeaakiabeo8aZnaaCaaaleqabaGaaiOkaaaaaOGaay jkaiaawMcaaaGaay5waiaaw2faaaWceaqabeaacaWGjbGaamOBaiaa dAgacaWGSbGaamyDaiaadwgacaWGUbGaam4yaiaadwgafaqabeqaba aabaaaaiaad+gacaWGMbaabaqbaeqabeqaaaqaaaaacaWG0bGaamOC aiaadMgacaWGHbGaamiEaiaadMgacaWGHbGaamiBaiaadMgacaWG0b GaamyEaaaakiaawIJ=amaayaaabaWaamWaaeaacaaIXaGaey4kaSIa amiramaaBaaaleaacaaI0aaabeaakiGacYgacaGGUbWaaeWaaeaacu aH1oqzgaGaamaaCaaaleqabaGaaiOkaaaaaOGaayjkaiaawMcaaaGa ay5waiaaw2faaaWceaqabeaacaWGjbGaamOBaiaadAgacaWGSbGaam yDaiaadwgacaWGUbGaam4yaiaadwgafaqabeqabaaabaaaaiaad+ga caWGMbaabaqbaeqabeqaaaqaaaaacaWGZbGaamiDaiaadkhacaWGHb GaamyAaiaad6gafaqabeqabaaabaaaaiaadkhacaWGHbGaamiDaiaa dwgaaaGccaGL44padaagaaqaamaadmaabaGaaGymaiabgUcaRiaads eadaWgaaWcbaGaaGynaaqabaGccaWGubWaaWbaaSqabeaacaGGQaaa aaGccaGLBbGaayzxaaaaleaafaqabeqabaaaeaqabeaacaWGjbGaam OBaiaadAgacaWGSbGaamyDaiaadwgacaWGUbGaam4yaiaadwgafaqa beqabaaabaaaaiaad+gacaWGMbaabaGaamiDaiaadwgacaWGTbGaam iCaiaadwgacaWGYbGaamyyaiaadshacaWG1bGaamOCaiaadwgaaaaa aOGaayjo+daaaa@A0E3@
ここで、
ε f MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqLqFfpeea0xe9vq=Jb9 vqpeea0xd9q8qiYRWxGi6xij=hbba9q8aq0=yq=He9q8qiLsFr0=vr 0=vr0db8meaabaqaciGacaGaaeqabaWaaeaaeaaakeaacqaH1oqzda WgaaWcbaGaamOzaaqabaaaaa@3A2A@
塑性破壊ひずみ
ε ˙ * = ε ˙ ε ˙ 0 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGafqyTduMbai aadaahaaWcbeqaaiaacQcaaaGccqGH9aqpdaWcaaqaaiqbew7aLzaa caaabaGafqyTduMbaiaadaWgaaWcbaGaaGimaaqabaaaaaaa@3DE8@
入力参照ひずみ速度で割られた現在のひずみ速度
T * MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqLqFfpeea0xe9vq=Jb9 vqpeea0xd9q8qiYRWxGi6xij=hbba9q8aq0=yq=He9q8qiLsFr0=vr 0=vr0db8meaabaqaciGacaGaaeqabaWaaeaaeaaakeaacaWGubWaaW baaSqabeaacaGGQaaaaaaa@3920@
材料則または/HEAT/MATで計算
ひずみ速度と温度を無視したJohnson-Cook破壊のプロットは:


図 1. Johnson-Cook破壊モデルのプロットの例

曲線より上の塑性ひずみは材料破壊あり、曲線より下は材料破壊なしを表します。

軸性の影響のみが考慮される簡単なケースでは、破壊ひずみは:(2)
ε f = D 1 + D 2 exp ( D 3 σ * ) MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbb a9q8WqFfeaY=biLkVcLq=JHqpepeea0=as0Fb9pgeaYRXxe9vr0=vr 0=vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOqaaabaaaaaaaaape GaeqyTdu2damaaBaaaleaapeGaamOzaaWdaeqaaOWdbiabg2da9iaa bseapaWaaSbaaSqaa8qacaaIXaaapaqabaGcpeGaey4kaSIaaeira8 aadaWgaaWcbaWdbiaaikdaa8aabeaak8qacqGHflY1caqGLbGaaeiE aiaabchadaqadaWdaeaapeGaaeira8aadaWgaaWcbaWdbiaaiodaa8 aabeaak8qacqGHflY1cqaHdpWCpaWaaWbaaSqabeaapeGaaiOkaaaa aOGaayjkaiaawMcaaaaa@4CB8@
試験からの3つの破壊データポイントを使用すると:
  • ε f = 0.1585 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbb a9q8WqFfeaY=biLkVcLq=JHqpepeea0=as0Fb9pgeaYRXxe9vr0=vr 0=vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOqaaabaaaaaaaaape GaeqyTdu2damaaBaaaleaapeGaamOzaaWdaeqaaOWdbiabg2da9iaa icdacaGGUaGaaGymaiaaiwdacaaI4aGaaGynaaaa@3E7F@ (単軸引張( σ * = 1 / 3 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbb a9q8WqFfeaY=biLkVcLq=JHqpepeea0=as0Fb9pgeaYRXxe9vr0=vr 0=vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOqaaabaaaaaaaaape Gaeq4Wdm3damaaCaaaleqabaWdbiaacQcaaaGccqGH9aqpcaaIXaGa ai4laiaaiodaaaa@3C04@ )による)
  • ε f = 0.19 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbb a9q8WqFfeaY=biLkVcLq=JHqpepeea0=as0Fb9pgeaYRXxe9vr0=vr 0=vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOqaaabaaaaaaaaape GaeqyTdu2damaaBaaaleaapeGaamOzaaWdaeqaaOWdbiabg2da9iaa icdacaGGUaGaaGymaiaaiMdaaaa@3D02@ (純せん断( σ * = 0 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbb a9q8WqFfeaY=biLkVcLq=JHqpepeea0=as0Fb9pgeaYRXxe9vr0=vr 0=vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOqaaabaaaaaaaaape Gaeq4Wdm3damaaCaaaleqabaWdbiaacQcaaaGccqGH9aqpcaaIWaaa aa@3A93@ )による)
  • ε f = 0.2419 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbb a9q8WqFfeaY=biLkVcLq=JHqpepeea0=as0Fb9pgeaYRXxe9vr0=vr 0=vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOqaaabaaaaaaaaape GaeqyTdu2damaaBaaaleaapeGaamOzaaWdaeqaaOWdbiabg2da9iaa icdacaGGUaGaaGOmaiaaisdacaaIXaGaaGyoaaaa@3E7C@ (単軸圧縮( σ * = 1 / 3 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbb a9q8WqFfeaY=biLkVcLq=JHqpepeea0=as0Fb9pgeaYRXxe9vr0=vr 0=vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOqaaabaaaaaaaaape Gaeq4Wdm3damaaCaaaleqabaWdbiaacQcaaaGccqGH9aqpcqGHsisl caaIXaGaai4laiaaiodaaaa@3CF1@ )による)
パラメータ D 1 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbb a9q8WqFfeaY=biLkVcLq=JHqpepeea0=as0Fb9pgeaYRXxe9vr0=vr 0=vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOaeaaaaaaaaa8qaba Gaaeira8aadaWgaaWcbaWdbiaaigdaa8aabeaaaaa@37E8@ D 2 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbb a9q8WqFfeaY=biLkVcLq=JHqpepeea0=as0Fb9pgeaYRXxe9vr0=vr 0=vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOaeaaaaaaaaa8qaba Gaaeira8aadaWgaaWcbaWdbiaaigdaa8aabeaaaaa@37E8@ および D 3 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbb a9q8WqFfeaY=biLkVcLq=JHqpepeea0=as0Fb9pgeaYRXxe9vr0=vr 0=vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOaeaaaaaaaaa8qaba Gaaeira8aadaWgaaWcbaWdbiaaigdaa8aabeaaaaa@37E8@ は、以下の方程式を解くことによって解析学的に計算されます:(3)
{ 0.1585 = D 1 + D 2 exp ( D 3 1 3 ) 0.19 = D 1 + D 2 exp ( D 3 0 ) 0.2419 = D 1 + D 2 exp ( D 3 1 3 ) MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVCI8FfYJH8YrFfeuY=Hhbbf9v8qqaqFr0xc9pk0xbb a9q8WqFfeaY=biLkVcLq=JHqpepeea0=as0Fb9pgeaYRXxe9vr0=vr 0=vqpWqaaeaabiGaciaacaqabeaadaqaaqaaaOqaaabaaaaaaaaape WaaiqaaeaafaqabeWabaaabaGaaGimaiaac6cacaaIXaGaaGynaiaa iIdacaaI1aGaeyypa0Jaaeira8aadaWgaaWcbaWdbiaaigdaa8aabe aak8qacqGHRaWkcaqGebWdamaaBaaaleaapeGaaGOmaaWdaeqaaOWd biabgwSixlaabwgacaqG4bGaaeiCamaabmaapaqaa8qacaqGebWdam aaBaaaleaacaaIZaaabeaak8qacqGHflY1daWcaaqaaiaaigdaaeaa caaIZaaaaaGaayjkaiaawMcaaaqaaiaaicdacaGGUaGaaGymaiaaiM dacqGH9aqpcaqGebWdamaaBaaaleaapeGaaGymaaWdaeqaaOWdbiab gUcaRiaabseapaWaaSbaaSqaa8qacaaIYaaapaqabaGcpeGaeyyXIC TaaeyzaiaabIhacaqGWbWaaeWaa8aabaWdbiaabseapaWaaSbaaSqa aiaaiodaaeqaaOWdbiabgwSixlaaicdaaiaawIcacaGLPaaaaeaaca aIWaGaaiOlaiaaikdacaaI0aGaaGymaiaaiMdacqGH9aqpcaqGebWd amaaBaaaleaapeGaaGymaaWdaeqaaOWdbiabgUcaRiaabseapaWaaS baaSqaa8qacaaIYaaapaqabaGcpeGaeyyXICTaaeyzaiaabIhacaqG WbWaaeWaa8aabaWdbiaabseapaWaaSbaaSqaaiaaiodaaeqaaOWdbi abgwSixlabgkHiTmaalaaabaGaaGymaaqaaiaaiodaaaaacaGLOaGa ayzkaaaaaaGaay5Eaaaaaa@79E1@

要素破壊処理

損傷累積法は、要素内にで発生した塑性ひずみの量を以下を用いて合計するために使用されます:(4)
D = Δ ε p ε f 1 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiraiabg2 da9maaqaeabaWaaSaaaeaacaqGuoGaeqyTdu2aaSbaaSqaaiaadcha aeqaaaGcbaGaeqyTdu2aaSbaaSqaaiaadAgaaeqaaaaakiabgwMiZk aaigdaaSqabeqaniabggHiLdaaaa@431F@
D 1 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbbG8FasPYRqj0=yi0dXdbba9pGe9xq=JbbG8A8frFve9 Fve9Ff0dmeaabaqaciGacaGaaeqabaWaaeaaeaaakeaacaWGebGaey yzImRaaGymaaaa@39A9@ が要素破壊フラグ(Ifail_shIfail_so)およびXFEM定式化フラグ(Ixfem)の値に依存して起こること。XFEM定式化が使用されていない際(Ixfem=0)、以下の表は、異なる要素破壊フラグをまとめています。
表 1. 要素破壊オプション
要素 要素破壊フラグ 次の場合; D 1 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbbG8FasPYRqj0=yi0dXdbba9pGe9xq=JbbG8A8frFve9 Fve9Ff0dmeaabaqaciGacaGaaeqabaWaaeaaeaaakeaacaWGebGaey yzImRaaGymaaaa@39A9@ 破壊挙動
シェル Ifail_sh=1

(デフォルト)

1 IPまたは層で 削除される要素
シェル Ifail_sh=2 1 IPまたは層で 応力テンソルはIPまたは層でゼロに設定
シェル Ifail_sh=2 すべてのIPまたは層で 削除される要素
ソリッド Ifail_sh=1

(デフォルト)

1 IPで 削除される要素
ソリッド Ifail_sh=2 1 IPで 応力テンソルはIPでゼロに設定
ソリッド Ifail_sh=2 すべてのIP 応力テンソルは要素でゼロに設定

XFEM定式化(Ixfem=1)の詳細は、/FAIL/JOHNSONに見つかります。

損傷 D MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiraaaa@36C0@ は、/ANIM/SHELL/DAMAまた/ANIM/BRICK/DAMAを使ってアニメーションファイル内でプロットすることができます。これは、材料損傷のリスクを示します。