Решение Michell

Решение Мичелла представляет собой общее решение уравнений упругости в полярных координатах ( ), разработанное Дж . Х. Мичеллом . Решение таково, что компоненты напряжения представлены в виде ряда Фурье по .${\ Displaystyle г, \ тета \,}$${\ displaystyle \ theta \,}$

Мичелл ^[1] показал, что общее решение может быть выражено через функцию напряжений Эйри вида

${\displaystyle {\begin{aligned}\varphi (r,\theta )&=A_{0}~r^{2}+B_{0}~r^{2}~\ln(r)+C_{0}~\ln(r)\\&+\left(I_{0}~r^{2}+I_{1}~r^{2}~\ln(r)+I_{2}~\ln(r)+I_{3}~\right)\theta \\&+\left(A_{1}~r+B_{1}~r^{-1}+B_{1}^{'}~r~\theta +C_{1}~r^{3}+D_{1}~r~\ln(r)\right)\cos \theta \\&+\left(E_{1}~r+F_{1}~r^{-1}+F_{1}^{'}~r~\theta +G_{1}~r^{3}+H_{1}~r~\ln(r)\right)\sin \theta \\&+\sum _{n=2}^{\infty }\left(A_{n}~r^{n}+B_{n}~r^{-n}+C_{n}~r^{n+2}+D_{n}~r^{-n+2}\right)\cos(n\theta )\\&+\sum _{n=2}^{\infty }\left(E_{n}~r^{n}+F_{n}~r^{-n}+G_{n}~r^{n+2}+H_{n}~r^{-n+2}\right)\sin(n\theta )\end{aligned}}}$

Термины и определяют тривиальное нулевое стрессовое состояние и игнорируются.${\displaystyle A_{1}~r~\cos \theta \,}$${\displaystyle E_{1}~r~\sin \theta \,}$

Компоненты напряжения [ править ]

Компоненты напряжения могут быть получены путем подстановки решения Мичелла в уравнения для напряжения в терминах функции напряжения Эйри (в цилиндрических координатах ). Таблица компонентов напряжения приведена ниже. ^[2]

${\displaystyle \varphi }$	${\displaystyle \sigma _{rr}\,}$	${\displaystyle \sigma _{r\theta }\,}$	${\displaystyle \sigma _{\theta \theta }\,}$
${\displaystyle r^{2}\,}$	${\displaystyle 2}$	${\displaystyle 0}$	${\displaystyle 2}$
${\displaystyle r^{2}~\ln r}$	${\displaystyle 2~\ln r+1}$	${\displaystyle 0}$	${\displaystyle 2~\ln r+3}$
${\displaystyle \ln r\,}$	${\displaystyle r^{-2}\,}$	${\displaystyle 0}$	${\displaystyle -r^{-2}\,}$
${\displaystyle \theta \,}$	${\displaystyle 0}$	${\displaystyle r^{-2}\,}$	${\displaystyle 0}$
${\displaystyle r^{3}~\cos \theta \,}$	${\displaystyle 2~r~\cos \theta \,}$	${\displaystyle 2~r~\sin \theta \,}$	${\displaystyle 6~r~\cos \theta \,}$
${\displaystyle r\theta ~\cos \theta \,}$	${\displaystyle -2~r^{-1}~\sin \theta \,}$	${\displaystyle 0}$	${\displaystyle 0}$
${\displaystyle r~\ln r~\cos \theta \,}$	${\displaystyle r^{-1}~\cos \theta \,}$	${\displaystyle r^{-1}~\sin \theta \,}$	${\displaystyle r^{-1}~\cos \theta \,}$
${\displaystyle r^{-1}~\cos \theta \,}$	${\displaystyle -2~r^{-3}~\cos \theta \,}$	${\displaystyle -2~r^{-3}~\sin \theta \,}$	${\displaystyle 2~r^{-3}~\cos \theta \,}$
${\displaystyle r^{3}~\sin \theta \,}$	${\displaystyle 2~r~\sin \theta \,}$	${\displaystyle -2~r~\cos \theta \,}$	${\displaystyle 6~r~\sin \theta \,}$
${\displaystyle r\theta ~\sin \theta \,}$	${\displaystyle 2~r^{-1}~\cos \theta \,}$	${\displaystyle 0}$	${\displaystyle 0}$
${\displaystyle r~\ln r~\sin \theta \,}$	${\displaystyle r^{-1}~\sin \theta \,}$	${\displaystyle -r^{-1}~\cos \theta \,}$	${\displaystyle r^{-1}~\sin \theta \,}$
${\displaystyle r^{-1}~\sin \theta \,}$	${\displaystyle -2~r^{-3}~\sin \theta \,}$	${\displaystyle 2~r^{-3}~\cos \theta \,}$	${\displaystyle 2~r^{-3}~\sin \theta \,}$
${\displaystyle r^{n+2}~\cos(n\theta )\,}$	${\displaystyle -(n+1)(n-2)~r^{n}~\cos(n\theta )\,}$	${\displaystyle n(n+1)~r^{n}~\sin(n\theta )\,}$	${\displaystyle (n+1)(n+2)~r^{n}~\cos(n\theta )\,}$
${\displaystyle r^{-n+2}~\cos(n\theta )\,}$	${\displaystyle -(n+2)(n-1)~r^{-n}~\cos(n\theta )\,}$	${\displaystyle -n(n-1)~r^{-n}~\sin(n\theta )\,}$	${\displaystyle (n-1)(n-2)~r^{-n}~\cos(n\theta )}$
${\displaystyle r^{n}~\cos(n\theta )\,}$	${\displaystyle -n(n-1)~r^{n-2}~\cos(n\theta )\,}$	${\displaystyle n(n-1)~r^{n-2}~\sin(n\theta )\,}$	${\displaystyle n(n-1)~r^{n-2}~\cos(n\theta )\,}$
${\displaystyle r^{-n}~\cos(n\theta )\,}$	${\displaystyle -n(n+1)~r^{-n-2}~\cos(n\theta )\,}$	${\displaystyle -n(n+1)~r^{-n-2}~\sin(n\theta )\,}$	${\displaystyle n(n+1)~r^{-n-2}~\cos(n\theta )\,}$
${\displaystyle r^{n+2}~\sin(n\theta )\,}$	${\displaystyle -(n+1)(n-2)~r^{n}~\sin(n\theta )\,}$	${\displaystyle -n(n+1)~r^{n}~\cos(n\theta )\,}$	${\displaystyle (n+1)(n+2)~r^{n}~\sin(n\theta )\,}$
${\displaystyle r^{-n+2}~\sin(n\theta )\,}$	${\displaystyle -(n+2)(n-1)~r^{-n}~\sin(n\theta )\,}$	${\displaystyle n(n-1)~r^{-n}~\cos(n\theta )\,}$	${\displaystyle (n-1)(n-2)~r^{-n}~\sin(n\theta )\,}$
${\displaystyle r^{n}~\sin(n\theta )\,}$	${\displaystyle -n(n-1)~r^{n-2}~\sin(n\theta )\,}$	${\displaystyle -n(n-1)~r^{n-2}~\cos(n\theta )\,}$	${\displaystyle n(n-1)~r^{n-2}~\sin(n\theta )\,}$
${\displaystyle r^{-n}~\sin(n\theta )\,}$	${\displaystyle -n(n+1)~r^{-n-2}~\sin(n\theta )\,}$	${\displaystyle n(n+1)~r^{-n-2}~\cos(n\theta )\,}$	${\displaystyle n(n+1)~r^{-n-2}~\sin(n\theta )\,}$

Компоненты смещения [ править ]

Смещения могут быть получены из решения Мичелла с использованием соотношений напряжение-деформация и деформация-смещение . Таблица компонентов смещения, соответствующих членам функции напряжения Эйри для решения Michell, приведена ниже. В этой таблице${\displaystyle (u_{r},u_{\theta })}$

${\displaystyle \kappa ={\begin{cases}3-4~\nu &{\rm {for~plane~strain}}\\{\cfrac {3-\nu }{1+\nu }}&{\rm {for~plane~stress}}\\\end{cases}}}$

где - коэффициент Пуассона , - модуль сдвига .${\displaystyle \nu }$${\displaystyle \mu }$

${\displaystyle \varphi }$	${\displaystyle 2~\mu ~u_{r}\,}$	${\displaystyle 2~\mu ~u_{\theta }\,}$
${\displaystyle r^{2}\,}$	${\displaystyle (\kappa -1)~r}$	${\displaystyle 0}$
${\displaystyle r^{2}~\ln r}$	${\displaystyle (\kappa -1)~r~\ln r-r}$	${\displaystyle (\kappa +1)~r~\theta }$
${\displaystyle \ln r\,}$	${\displaystyle -r^{-1}\,}$	${\displaystyle 0}$
${\displaystyle \theta \,}$	${\displaystyle 0}$	${\displaystyle -r^{-1}\,}$
${\displaystyle r^{3}~\cos \theta \,}$	${\displaystyle (\kappa -2)~r^{2}~\cos \theta \,}$	${\displaystyle (\kappa +2)~r^{2}~\sin \theta \,}$
${\displaystyle r\theta ~\cos \theta \,}$	${\displaystyle {\frac {1}{2}}[(\kappa -1)\theta ~\cos \theta +\{1-(\kappa +1)\ln r\}~\sin \theta ]\,}$	${\displaystyle -{\frac {1}{2}}[(\kappa -1)\theta ~\sin \theta +\{1+(\kappa +1)\ln r\}~\cos \theta ]\,}$
${\displaystyle r~\ln r~\cos \theta \,}$	${\displaystyle {\frac {1}{2}}[(\kappa +1)\theta ~\sin \theta -\{1-(\kappa -1)\ln r\}~\cos \theta ]\,}$	${\displaystyle {\frac {1}{2}}[(\kappa +1)\theta ~\cos \theta -\{1+(\kappa -1)\ln r\}~\sin \theta ]\,}$
${\displaystyle r^{-1}~\cos \theta \,}$	${\displaystyle r^{-2}~\cos \theta \,}$	${\displaystyle r^{-2}~\sin \theta \,}$
${\displaystyle r^{3}~\sin \theta \,}$	${\displaystyle (\kappa -2)~r^{2}~\sin \theta \,}$	${\displaystyle -(\kappa +2)~r^{2}~\cos \theta \,}$
${\displaystyle r\theta ~\sin \theta \,}$	${\displaystyle {\frac {1}{2}}[(\kappa -1)\theta ~\sin \theta -\{1-(\kappa +1)\ln r\}~\cos \theta ]\,}$	${\displaystyle {\frac {1}{2}}[(\kappa -1)\theta ~\cos \theta -\{1+(\kappa +1)\ln r\}~\sin \theta ]\,}$
${\displaystyle r~\ln r~\sin \theta \,}$	${\displaystyle -{\frac {1}{2}}[(\kappa +1)\theta ~\cos \theta +\{1-(\kappa -1)\ln r\}~\sin \theta ]\,}$	${\displaystyle {\frac {1}{2}}[(\kappa +1)\theta ~\sin \theta +\{1+(\kappa -1)\ln r\}~\cos \theta ]\,}$
${\displaystyle r^{-1}~\sin \theta \,}$	${\displaystyle r^{-2}~\sin \theta \,}$	${\displaystyle -r^{-2}~\cos \theta \,}$
${\displaystyle r^{n+2}~\cos(n\theta )\,}$	${\displaystyle (\kappa -n-1)~r^{n+1}~\cos(n\theta )\,}$	${\displaystyle (\kappa +n+1)~r^{n+1}~\sin(n\theta )\,}$
${\displaystyle r^{-n+2}~\cos(n\theta )\,}$	${\displaystyle (\kappa +n-1)~r^{-n+1}~\cos(n\theta )\,}$	${\displaystyle -(\kappa -n+1)~r^{-n+1}~\sin(n\theta )\,}$
${\displaystyle r^{n}~\cos(n\theta )\,}$	${\displaystyle -n~r^{n-1}~\cos(n\theta )\,}$	${\displaystyle n~r^{n-1}~\sin(n\theta )\,}$
${\displaystyle r^{-n}~\cos(n\theta )\,}$	${\displaystyle n~r^{-n-1}~\cos(n\theta )\,}$	${\displaystyle n(~r^{-n-1}~\sin(n\theta )\,}$
${\displaystyle r^{n+2}~\sin(n\theta )\,}$	${\displaystyle (\kappa -n-1)~r^{n+1}~\sin(n\theta )\,}$	${\displaystyle -(\kappa +n+1)~r^{n+1}~\cos(n\theta )\,}$
${\displaystyle r^{-n+2}~\sin(n\theta )\,}$	${\displaystyle (\kappa +n-1)~r^{-n+1}~\sin(n\theta )\,}$	${\displaystyle (\kappa -n+1)~r^{-n+1}~\cos(n\theta )\,}$
${\displaystyle r^{n}~\sin(n\theta )\,}$	${\displaystyle -n~r^{n-1}~\sin(n\theta )\,}$	${\displaystyle -n~r^{n-1}~\cos(n\theta )\,}$
${\displaystyle r^{-n}~\sin(n\theta )\,}$	${\displaystyle n~r^{-n-1}~\sin(n\theta )\,}$	${\displaystyle -n~r^{-n-1}~\cos(n\theta )\,}$

Обратите внимание, что смещение твердого тела может быть наложено на решение Мичелла вида

${\displaystyle {\begin{aligned}u_{r}&=A~\cos \theta +B~\sin \theta \\u_{\theta }&=-A~\sin \theta +B~\cos \theta +C~r\\\end{aligned}}}$

для получения допустимого поля смещения.

Ссылки [ править ]

См. Также [ править ]

• Линейная эластичность
• Flamant раствор
• Джон Генри Мичелл