Лекции Сопротивление материалов
.pdfvk.com/club152685050 | vk.com/id446425943
vk.com/club152685050 | vk.com/id446425943
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= 2 2 |
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1 1 2 |
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(5) |
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1 1+ 2 2 |
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= 2 2∙0+ 1 1∙0 = 0 |
(6) |
1 1+ 2 2
vk.com/club152685050 | vk.com/id446425943
vk.com/club152685050 | vk.com/id446425943
= 2 2∙0+ 1 1∙ |
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2+ 1 > 0 |
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(7) |
1 1+ 2 2
= 2 2∙0+ 1 1∙0 = 0 |
(8) |
1 1+ 2 2
vk.com/club152685050 | vk.com/id446425943
vk.com/club152685050 | vk.com/id446425943
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∙0− 2 |
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< 0 |
(9) |
− 2 |
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∙0− 2 |
∙0 |
= 0 |
(10) |
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− 2 |
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vk.com/club152685050Преобразование| vk.com/id446425943 моментов инерции
при параллельном переносе осей координат
, → 1, 1
= 1 + , |
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= 1 + |
(11) |
vk.com/club152685050 | vk.com/id446425943
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2 , = |
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(12) |
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− 2 = |
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1 |
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2 − 2 + 2 = |
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− 2 |
+ 2 |
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+ 2 |
(13) |
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vk.com/club152685050 | vk.com/id446425943
Если ось y центральная ( = 0)
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+ 2 |
(14) |
1 |
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Аналогично:
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− 2 |
+ 2 |
(15) |
1 |
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Если ось z центральная, то 1 = + 2
vk.com/club152685050 | vk.com/id446425943
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1 1 |
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= − − + =
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(16) |
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Если оси y, z центральные ( = = 0)
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(17) |
1 1 |
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Если оси y, z центральные ( |
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= 0) и |
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главные ( |
= 0) |
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(18) |
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1 1 |
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