电大土木工程力学形成性考核册(作业一)小抄参考

1、土木工程力学（本）形成性考核册 作业一1、 选择题（每小题2分，共20分） 1三刚片组成几何不变体系的规则是（ b ）a 三链杆相联，不平行也不相交于一点 b 三铰两两相联，三铰不在一直线上c 三铰三链杆相联，杆不通过铰 d 一铰一链杆相联，杆不过铰2在无多余约束的几何不变体系上增加二元体后构成（ c ）a 可变体系 b 瞬变体系c 无多余约束的几何不变体系 d 有多余约束的几何不变体系3瞬变体系在一般荷载作用下，（ c ）a产生很小的内力 b不产生内力c产生很大的内力 d不存在静力解答4已知某体系的计算自由度w=-3，则体系的（ d ）a自由度为3 b自由度等于0c 多余约束数等于3 d 多

2、余约束数大于等于35不能作为建筑结构使用的是（ d ）a无多余约束的几何不变体系 b有多余约束的几何不变体系c 几何不变体系 d几何可变体系6图示桁架有几根零杆（ d ）a 0 b 2 c 4 d 67下图所示结构的弯矩图形状应为（ a ）8图示多跨静定梁的基本部分是（ b ）a ab部分 b bc部分 c cd部分 d de部分 9荷载作用下产生桁架位移的主要原因是（ a ） a 轴向变形 b 弯曲变形c 剪切变形 d 扭转变形10三铰拱在集中力作用下其合理拱轴线形状是（ d ）a 折线 b 圆弧 c 双曲线 d 抛物线2、 判断题（每小题2分，共20分）1多余约束是体系中不需要的约束。（

3、）2如果体系的计算自由度大于零，那么体系一定是几何可变体系。（ ）3两根链杆的约束作用相当于一个单铰。（ ）4一个体系是有n个自由度的几何可变体系，那么加入n个约束后就成为无多余约束的几何不变体系。（ ）5两刚片用三链杆相联，且三链杆平行不等长，则构成瞬变体系。 （ ）6图示两个单跨梁，同跨度同荷载。但横截面形状不同，故其内力也不相同。（ ）7三铰拱的矢高f越大，水平推力也越大。（ ）8求桁架内力时截面法所截取的隔离体包含两个或两个以上的结点。（ ）9某荷载作用下桁架可能存在零杆，它不受内力，因此在实际结构中可以将其去掉。（ ） 10试判断下列弯矩图是否正确。（ ）三、试对图示平面体系进行几何

4、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： 作弯矩图如下：20kn/m40kn2m4mabcd40kn2m2m2mef3abcefd4040120m图（knm）解： 作

5、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）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

6、at full-back but is still recovering from a knee injury aggravated against usa.both sides boast 100% records 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 com

7、petitions top try scorer with nine, closely followed by tuivasa-sheck with eight.but it is recently named rugby 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

8、chance of becoming the first player to win the world cup in both rugby league and rugby union after triumphing 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

9、head of fifas anti-racism taskforce, is in london for the football associations 150th anniversary celebrations 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 an

10、d i would like to speak to him first to find out what his experience was.uefa hasopened disciplinary proceedings 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

11、 referees actions.cska said they were surprised and disappointed by toures complaint. in a statement the russian 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 im

12、portant role in this mission. starting at the ground, conditions have to be very calm - winds less than 2 mph, 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 wea

13、ther lives. it will climb higher than the tip of mount everest (5.5 miles/8.85 kilometers), drifting even higher 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 tu

14、rbulence.the balloon will slowly drift to the edge of space at 120,000 feet ( then, i would assume, he will slowly 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 ma

15、nchester.five years ago they cruised through to the final and so far history has repeated itself here - the last 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 ka

16、ngaroos focus in their games since then.they have been concentrating on the sort of stuff that wins you tough, 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 sta

17、nds 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 satur