Ssg c my ny:
1) Din gii cc gi tr nhn c t lnh massprop, vi i tng Region:Area:
Din tchPerimeter: Chu viBounding box: Kch thc gii hnCentroid: Trng
tmMoments of inertia: M men qun tnh (i vi cc trc X, Y)Product of
inertia: M men qun tnh ly tm (i vi h trc OXY)Radii of gyration: Bn
knh qun tnhPrincipal moments and X-Y directions about centroid: M
men qun tnh chnh v chiu ca h trc qun tnh chnh trung tm.Along
[1.0000 0.0000] c hiu l: theo trc c xc nh bi im centroid v im c to
tng i vi n [1.0 ; 0.0]
2) Tnh momen tnh l bc tnh trung gian xc nh trng tm mt ct (khi lm
th cng). y c centroid ri -> tnh momen tnh l khng cn thit (nu mun
tnh th ly din tch mt ct nhn vi khong cch t trng tm n trc cn tnh).
Lu thm: ng nh cc bn nh chnh, th nguyn ca momen tnh l [chiu di]^3.
Ngoi ra, momen tnh i vi mi trc i qua centroid bng 0.
3) Nhc li vi quan trng trong Sc bn:- Mt h trc c Product of
inertia Jxy = 0 gi l h trc qun tnh chnh- Nu mt ct c 1 trc i xng th
bt k trc no vung gc vi trc i xng cng lp vi n 1 h trc qun tnh chnh.-
H trc qun tnh chnh c gc ti trng tm mt ct gi l h trc qun tnh chnh
trung tm.
4) Nu h trc Oxy trng vi h trc qun tnh chnh trung tm th cc gi tr
ca Moments of inertia v Principal moments trng nhau.
5) Thay v move mt ct v gc to , ta c th di trc to (lnh Origin
UCS) n trng tm mt ct v gi massprop. Kt qu nhn c nh nhau.
6) Nu mt ct c t nht 1 trc i xng song song vi mt trong cc trc Ox
hoc Oy (gc O tu ) th khng cn di mt ct ln trc to . C yn nh vy, gi
massprop v ly kt qu Principal moments (I, J) tnh ton.
7) Acad khng tnh sn momen chng un. Mun tnh th ly Moment of
inertia chia cho Ymax (hoc Xmax)
8) Bn no cn l t m v cc khi nim th xin mi lt gio trnh Sc bn ra
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