電大土木工程力學(xué)形成性考核冊(作業(yè)一)小抄參考

1、專業(yè)好文檔土木工程力學(xué)（本）形成性考核冊 作業(yè)一1、 選擇題（每小題2分，共20分） 1三剛片組成幾何不變體系的規(guī)則是（ b ）a 三鏈桿相聯(lián)，不平行也不相交于一點(diǎn) b 三鉸兩兩相聯(lián)，三鉸不在一直線上c 三鉸三鏈桿相聯(lián)，桿不通過鉸 d 一鉸一鏈桿相聯(lián)，桿不過鉸2在無多余約束的幾何不變體系上增加二元體后構(gòu)成（ c ）a 可變體系 b 瞬變體系c 無多余約束的幾何不變體系 d 有多余約束的幾何不變體系3瞬變體系在一般荷載作用下，（ c ）a產(chǎn)生很小的內(nèi)力 b不產(chǎn)生內(nèi)力c產(chǎn)生很大的內(nèi)力 d不存在靜力解答4已知某體系的計算自由度w=-3，則體系的（ d ）a自由度為3 b自由度等于0c 多余約束數(shù)等于

2、3 d 多余約束數(shù)大于等于35不能作為建筑結(jié)構(gòu)使用的是（ d ）a無多余約束的幾何不變體系 b有多余約束的幾何不變體系c 幾何不變體系 d幾何可變體系6圖示桁架有幾根零桿（ d ）a 0 b 2 c 4 d 67下圖所示結(jié)構(gòu)的彎矩圖形狀應(yīng)為（ a ）8圖示多跨靜定梁的基本部分是（ b ）a ab部分 b bc部分 c cd部分 d de部分 9荷載作用下產(chǎn)生桁架位移的主要原因是（ a ） a 軸向變形 b 彎曲變形c 剪切變形 d 扭轉(zhuǎn)變形10三鉸拱在集中力作用下其合理拱軸線形狀是（ d ）a 折線 b 圓弧 c 雙曲線 d 拋物線2、 判斷題（每小題2分，共20分）1多余約束是體系中不需要的

3、約束。（ ）2如果體系的計算自由度大于零，那么體系一定是幾何可變體系。（ ）3兩根鏈桿的約束作用相當(dāng)于一個單鉸。（ ）4一個體系是有n個自由度的幾何可變體系，那么加入n個約束后就成為無多余約束的幾何不變體系。（ ）5兩剛片用三鏈桿相聯(lián)，且三鏈桿平行不等長，則構(gòu)成瞬變體系。 （ ）6圖示兩個單跨梁，同跨度同荷載。但橫截面形狀不同，故其內(nèi)力也不相同。（ ）7三鉸拱的矢高f越大，水平推力也越大。（ ）8求桁架內(nèi)力時截面法所截取的隔離體包含兩個或兩個以上的結(jié)點(diǎn)。（ ）9某荷載作用下桁架可能存在零桿，它不受內(nèi)力，因此在實際結(jié)構(gòu)中可以將其去掉。（ ） 10試判斷下列彎矩圖是否正確。（ ）三、試對圖示平面體

4、系進(jìn)行幾何組成分析。（每小題5分，共20分） 1解：由二元體分析法原結(jié)構(gòu)是一個無多余約束的幾何不變體系。2解：由二元體分析法原結(jié)構(gòu)是一個無多余約束的幾何不變體系。3解：顯然，體系是具有兩個多余約束的幾何不變體系。4解：由三剛片規(guī)則，可知體系是無多余約束的幾何不變體系。四、繪制下圖所示各結(jié)構(gòu)的彎矩圖。（每小題10分，共30分）110kn/m20kn3m1m3mabcdabcd56060(11.25)m圖（knm）作彎矩圖如下：l/2labcdl/2fpfpl2abcdfplm圖解： 作彎矩圖如下：20kn/m40kn2m4mabcd40kn2m2m2mef3abcefd4040120m圖（knm

5、）解： 作彎矩圖如下：123aabcdaaafpfpa五、計算圖示桁架中指定桿件的內(nèi)力。解：求支座反力 由 由 用-截面將桁架截開，保留右邊部分，受力如圖：cdfn1fn4fn3fp 由 （壓） 由 cfn2fn4fpfn4 （拉）取結(jié)點(diǎn)c為研究對象，作受力圖如下： 顯然：（壓）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 n

6、amed 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 th

7、e competitions 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

8、 the 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,

9、 the 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 fe

10、lt and 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 int

11、o the 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

12、an important 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-da

13、y weather 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

14、of turbulence.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

15、in manchester.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 t

16、he kangaroos 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 th

17、e 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 satu