江药科技大学jiangsu university of sclence and technology例8-1试用力矩分配法作弯矩图。200kN×6mMFAB1200kN820kN/m电光K= -150kNm.BPCEIEI6m3m3mMF-MFRAAB= 150kNm解(1)先在结点上约束,计算固端弯矩和约束力矩。20 kN/mx(6m)MF216BC84YBLA15015090= -90kNmMBLM, = 150kNm- 90kNm90kN·m150 kN-m= 60kNm
School of Civil Engine School of Civil Engineering and Architecture ring and Architecture 例8-1 试用力矩分配法作弯矩图。 解 (1)先在结点B加上约束,计算 固端弯矩和约束力矩。 F 200 kN 6m 8 150 kNm M AB F F 150 kNm M M BA AB 2 F 20 kN/m 6m 8 90 kNm M BC 150 kNm 90 kNm 60 kNm M B
江药科技大学jiangsu university of sclence and technology(2)放松结点B分配弯矩在B结点上加一个外力MBa = 0.571×(-60 kNm)偶-60kNm。然后,进行分配和= -34.3kNm传递。M Bc = 0.429×(-60 kNm)转动刚度= -25.7kNmSBA = 4iSBc = 3i传递弯矩分配系数14iM× M=0.571μBAABBA24i+3i= -17.2kNm3i=0. 429μBcMcr = 04i+3iSchool of Civil Engineering and Architecture
School of Civil Engine School of Civil Engineering and Architecture ring and Architecture (2)放松结点 B 在B结点上加一个外力 偶-60kNm。然后,进行分配和 传递。 4 3 S iS i BA BC 转动刚度 分配弯矩 ' ' 0.571 60 kNm 34.3 kNm 0.429 60 kNm 25.7 kNm BA BC M M 分配系数 4 4 3 3 4 3 BA Bc i i i i i i 传递弯矩 ' ' ' 1 2 17.2 kNm 0 AB BA CB M M M =0.571 =0.429
江蘇科技大学jiangsu university of sclence and technology(3)叠加得到最后的杆端弯矩0.5710.429分配系数ABC--90固端弯矩1500-150分配力矩0-17.2-34.3-25.7及传递力矩oll115.7115.7杆端弯矩-167.2167.2115.7300190BCA032.1M图(单位kN·m)158.5School of Civil Engineering and Architecture
School of Civil Engine School of Civil Engineering and Architecture ring and Architecture (3)叠加得到最后的杆端弯矩
江科技大学jiangsu university of science and technole88-2多结点的力矩分配DI8第一步,在结点B、C加约束,阻止结点的转动。DB第二步,去掉结点B的约束(结点C仍夹紧)。D第三步,重新夹紧结点B,然后去掉结点C的约束D3E重复第二步和第三步,连续梁的内力和变形很快达到实际状态。每放松一次结点就相当于进行一次单结点的分配与传递运算。SchoolofCivil EngineeringandArchitecture
School of Civil Engine School of Civil Engineering and Architecture ring and Architecture §8-2 多结点的力矩分配 第一步,在结点B、C加约 束,阻止结点的转动。 第二步,去掉结点B的约束 (结点C仍夹紧)。 第三步,重新夹紧结点B , 然后去掉结点C的约束。 ■重复第二步和第三步,连续梁的内力和变形很快达到实际状态。 ■每放松一次结点就相当于进行一次单结点的分配与传递运算
江蘇科技大学jiangsu university of sclence and technology20KN/m100KN【例8.2】/EI=1BEI=2EI=1TOTO4m4m6m6m解求固端弯矩q1?91220×62MFMF-60KN.m;60KN.mABBA121212FplFpl100×8MFMF-100KN·m;100KN·mBCCB888School of Civil Engineering and Architecture
School of Civil Engine School of Civil Engineering and Architecture ring and Architecture 【例8.2 】 解 : 1 求固端弯矩 KN m F l KN m M F l M KN m ql KN m M ql M F P CB F P BC F BA F AB 100 8 100 8 100 8 8 60 12 60 12 20 6 12 2 2 2 ; ; 20KN/m 100KN A B CD 6m 4m 4m 6m EI=1 EI=2 EI=1