电大土木工程力学形成性考核册小抄参考

1、作业一参考答案一、选择题1b2c3c4d5d6d7a8b9a10d二、判断题12345678910.三、试对图示平面体系进行几何组成分析。（每小题5分，共20分）1解：由二元体分析法原结构是一个无多余约束的几何不变体系。2解：由二元体分析法原结构是一个无多余约束的几何不变体系。3解：显然，体系是具有两个多余约束的几何不变体系。4解：由三刚片规则，可知体系是无多余约束的几何不变体系。四、绘制下图所示各结构的弯矩图。（每小题10分，共30分）110kn/m20kn3m1m3mabcdabcd56060(11.25)m图（knm）作弯矩图如下：l/2labcdl/2fpfpl2abcdfplm图解：

2、 作弯矩图如下：20kn/m40kn2m4mabcd40kn2m2m2mef3abcefd4040120m图（knm）解： 作弯矩图如下：123aabcdaaafpfpa五、计算图示桁架中指定杆件的内力。解：求支座反力 由 由 用-截面将桁架截开，保留右边部分，受力如图：cdfn1fn4fn3fp 由 （压） 由 cfn2fn4fpfn4 （拉）取结点c为研究对象，作受力图如下： 显然：（压）作业二参考答案一、选择题1d2c3b4d5d二、判断题12345九、用力法计算下列刚架。作业三参考答案一、选择题1a2c3d4d5a二、判断题12345作业四参考答案一、选择题1a2c3a4b5c二、判断

3、题12345三、画图示伸臂梁mk，fra的影响线。（10分）2m2mabc2mk解： 用机动法作影响线如下：abck1mk影响线1abc1/2fra影响线1四、绘制伸臂梁c截面、d截面的弯矩影响线和剪力影响线。（10分）1m3mdc1.5m0.5m解： 用机动法作影响线如下：c0.5mc影响线0.75c0.5fqc影响线0.750.25d1.5md影响线d1fqd影响线五、作图示梁fya、mc的影响线，并利用影响线计算图示荷载作用下的fya、mc值。（20分）2m2mac2m1mb12kn12kn8kn/m解：作fya、mc影响线如下：afya影响线10.25camc影响线1c计算fya、mc

4、的值： 六、试求图示体系的自振频率。ei=常数，杆长均为l。（10分）lml解：（1）计算柔度系数d11mp=1m图1ll0.5l用力法作图示m图，如图所示。由m图应用图乘法，可求得柔度系数d11 （2）体系自振频率w为： 七、求图示体系的自振频率。忽略杆件自身的质量。（15分）l/2mlml/2kei=a解：由下图列出体系动力学平衡方程：l/2mlml/2kei=ya对a点取矩，列出体系动力学平衡方程： 其中：和为惯性力，为弹性力。 又： ， ，代入动力学平衡方程，整理后得： 故得： 八、求图示体系的自振频率。质量m集中在横梁上。各杆ei=常数。（15分）eimheieiei1=解：取横梁为

5、研究对象，计算刚度系数k11由 结构的自振频率为： winger tuivasa-sheck, who scored two tries in the kiwis 20-18 semi-final win over england, has been passed fit after a lower-leg injury, while slater has been named at full-back but is still recovering from a knee injury aggravated against usa.both sides boast 100% records

6、heading into the encounter but australia have not conceded a try since josh charnleys effort in their first pool match against england on the opening day.aussie winger jarryd hayne is the competitions top try scorer with nine, closely followed by tuivasa-sheck with eight.but it is recently named rug

7、by league international federation player of the year sonny bill williams who has attracted the most interest in the tournament so far.the kiwi - with a tournament high 17 offloads - has the chance of becoming the first player to win the world cup in both rugby league and rugby union after triumphin

8、g with the all blacks in 2011.id give every award back in a heartbeat just to get across the line this weekend, said williams.the (lack of) air up there watch mcayman islands-based webb, the head of fifas anti-racism taskforce, is in london for the football associations 150th anniversary celebration

9、s and will attend citys premier league match at chelsea on sunday.i am going to be at the match tomorrow and i have asked to meet yaya toure, he told bbc sport.for me its about how he felt and i would like to speak to him first to find out what his experience was.uefa hasopened disciplinary proceedi

10、ngs against cskafor the racist behaviour of their fans duringcitys 2-1 win.michel platini, president of european footballs governing body, has also ordered an immediate investigation into the referees actions.cska said they were surprised and disappointed by toures complaint. in a statement the russ

11、ian side added: we found no racist insults from fans of cska. baumgartner the disappointing news: mission aborted.the supersonic descent could happen as early as sunda.the weather plays an important role in this mission. starting at the ground, conditions have to be very calm - winds less than 2 mph

12、, with no precipitation or humidity and limited cloud cover. the balloon, with capsule attached, will move through the lower level of the atmosphere (the troposphere) where our day-to-day weather lives. it will climb higher than the tip of mount everest (5.5 miles/8.85 kilometers), drifting even hig

13、her than the cruising altitude of commercial airliners (5.6 miles/9.17 kilometers) and into the stratosphere. as he crosses the boundary layer (called the tropopause),e can expect a lot of turbulence.the balloon will slowly drift to the edge of space at 120,000 feet ( then, i would assume, he will s

14、lowly step out onto something resembling an olympic diving platform.they blew it in 2008 when they got caught cold in the final and they will not make the same mistake against the kiwis in manchester.five years ago they cruised through to the final and so far history has repeated itself here - the l

15、ast try they conceded was scored by englands josh charnley in the opening game of the tournament.that could be classed as a weakness, a team under-cooked - but i have been impressed by the kangaroos focus in their games since then.they have been concentrating on the sort of stuff that wins you tough

16、, even contests - strong defence, especially on their own goal-line, completing sets and a good kick-chase. theyve been great at all the unglamorous stuff that often goes unnoticed in the stands but not by your team-mates.it is as though their entire tournament has been preparation for the final.in johnathan thurston, cooper cronk, cameron smith and either billy slater or greg inglis at full-back they have a spine that is unmatched in rugby league. they have played in so many high-pressure games - a priceless asset going into saturday.t