欧美精品一二区,性欧美一级,国产免费一区成人漫画,草久久久久,欧美性猛交ⅹxxx乱大交免费,欧美精品另类,香蕉视频免费播放

2019電大鋼結構(本)考試試題及答案匯總整編【完整打印版.doc

上傳人:good****022 文檔編號:116442251 上傳時間:2022-07-05 格式:DOC 頁數(shù):17 大?。?30KB
收藏 版權申訴 舉報 下載
2019電大鋼結構(本)考試試題及答案匯總整編【完整打印版.doc_第1頁
第1頁 / 共17頁
2019電大鋼結構(本)考試試題及答案匯總整編【完整打印版.doc_第2頁
第2頁 / 共17頁
2019電大鋼結構(本)考試試題及答案匯總整編【完整打印版.doc_第3頁
第3頁 / 共17頁

下載文檔到電腦,查找使用更方便

12 積分

下載資源

還剩頁未讀,繼續(xù)閱讀

資源描述:

《2019電大鋼結構(本)考試試題及答案匯總整編【完整打印版.doc》由會員分享,可在線閱讀,更多相關《2019電大鋼結構(本)考試試題及答案匯總整編【完整打印版.doc(17頁珍藏版)》請在裝配圖網(wǎng)上搜索。

1、【電大】鋼結構(本)匯總整編一、單項選擇題1下列關于我國目前的鋼結構設計說法正確的一項是( C )C.除疲勞計算按容許應力幅、應力按彈性狀態(tài)計算外,其他采用以概率理論為基礎的近似概率極限狀態(tài)設計方法2按承載力極限狀態(tài)設計鋼結構時,應考慮( C )C荷載效應的基本組合,必要時尚應考慮荷載效應的偶然組合3在結構設計中,失效概率與可靠指標的關系為( B )B 越大,越小,結構可靠性越差4下列鋼結構計算所取荷載設計值和標準值,符合鋼結構設計規(guī)范的一組是 ( B )B計算結構或構件的強度、穩(wěn)定性以及連接的強度時,應采用荷載設計值;5塔架和桅桿的結構形式屬于( A ) A高聳鋼結構 6相同跨度的結構承受相

2、同的荷載,普通鋼屋架的重量為鋼筋混凝土屋架的(B1/41/3)7在構件發(fā)生斷裂破壞前,具有明顯先兆的情況是( B ) B 塑性破壞 8鋼材的設計強度是根據(jù)( C )確定的 C屈服點 9鋼材的三項主要力學性能為( A ) A抗拉強度、屈服點、伸長率 10鋼材的伸長率是反映材料( D )的性能指標。 D 塑性變形能力11鋼結構對動力荷載適應性較強,是由于鋼材具有(C ) C良好的韌性 12四種厚度不等的16Mn鋼鋼板,其中( A )鋼板設計強度最高 A16mm 13鋼中硫和氧的含量超過限量時,會使鋼材( B ) B熱脆 14以下關于應力集中的說法中正確的是( B ) B應力集中產生同號應力場,使塑

3、性變形受到限制15鋼材在低溫下,沖擊韌性( B ) B降低16鋼材經(jīng)歷了應變硬化(應變強化)之后( A ) A強度提高 17下列因素與鋼構件發(fā)生脆性破壞無直接關系的是( A ) A鋼材屈服點的大小 18鋼材的疲勞破壞屬于( C ) C脆性破壞 19對鋼材的疲勞強度影響不顯著的是( C ) C鋼種 20沸騰鋼與鎮(zhèn)靜鋼冶煉澆注方法的主要不同之處是( C ) C沸騰鋼不加脫氧劑 1、焊接殘余應力不影響構件的( B ) B靜力強度 2、在彈性階段,側面角焊縫應力沿長度方向的分布為( C )C兩端大、中間小 3、焊縫長度方向與作用力垂直的角焊縫是( A )A正面角焊縫 4、關于重級工作制吊車焊接吊車梁的

4、腹板與上翼緣間的焊縫說法正確的是( D )D可采用二級焊透對接焊縫5、在鋼梁底面設有吊桿,其拉力設計值為650kN(靜載),吊桿通過節(jié)點板將荷載傳給鋼梁,節(jié)點板采用雙面焊縫焊于梁下翼緣,=10mm,=160MPa,則每面焊縫長度為(260mm)6、部分焊透的對接焊縫的計算應按( B )。B角焊縫 7、斜角焊縫主要用于( C )。C 鋼管結構 8、按照施焊位置分為平焊、橫焊、立焊及仰焊,其中操作條件最差的是( D )仰焊9、一個承受剪力作用的普通螺栓在抗剪連接中的承載力是( D )D A、B中的較小值10、C級普通螺栓連接可用于( B )B屋蓋支撐的連接 11、下列關于螺栓在構件排列的相關要求說

5、法有誤的一項是( A )A垂直于受力方向的受拉構件,各排螺栓的中距越小越好 12、承受軸心力作用的高強度螺栓摩擦型受剪切連接中,其凈截面強度驗算公式,下列與軸心拉桿所受的力相比關系正確的是( B )。B 13、高強度螺栓摩擦型連接和承壓型連接主要區(qū)別是(D)。D. 設計計算方法不同14、摩擦型連接的高強度螺栓在桿軸方向受拉時,其承載力說法正確的一項是( C )C與螺栓直徑有關 15、高強度螺栓摩擦型連接受剪破壞時,承載能力極限狀態(tài)的確定因素是( B )。B連接板件間的摩擦力 16、13在鋼梁底面設置吊桿,其拉力設計值為650kN,吊桿通過T形連接件將荷載傳給鋼梁,T形連接件與鋼梁下翼緣板采用雙

6、排88級M20高強度螺栓摩擦型連接,預拉力P=125kN,抗劃系數(shù)U=045,則高強度螺栓的數(shù)量應為( C )。C8 17、采用高強度螺栓摩擦型連接與承壓型連接,在相同螺栓直徑的條件下,它們對螺栓孔的要求是( A )A摩擦型連接孔要求略大,承壓型連接孔要求略小18、承壓型高強度螺栓可用于(D)。D 承受靜力荷載或間接承受動力荷載結構的連接19、每個受剪力作用的摩擦型高強度螺栓所受的拉力應低于其預拉力的(C)。C 08倍 20、圖1所示為高強度螺栓連接,在彎矩M的作用下,可以認為中和軸在(C螺栓 3上) 1、實腹式軸心受拉構件計算的內容包括(D)。D強度、剛度(長細比)2、對有孔眼等削弱的軸心拉

7、桿承載力,鋼結構設計規(guī)范采用的準則為凈截面( B )B平均應力達到鋼材屈服點 3、一寬度為、厚度為的鋼板上有一直徑為的孔,則鋼板的凈截面面積為( C )C 4、下列關于軸心壓桿的強度與穩(wěn)定的計算公式(為構件的凈截面,為構件的毛截面)正確的一項是( B ) 軸心壓桿的強度與穩(wěn)定,應分別滿足( B )。B 5、計算格構式軸心受壓柱整體穩(wěn)定時,用換算長細比代替,這是考慮( D )D綴材剪切變形的影響6、雙肢綴條式軸心受壓柱繞實軸和繞虛軸等穩(wěn)定的要求是(B )B 7、確定軸心受壓實腹柱的截面形式時,應使兩個主軸方向的長細比盡可能接近,其目的是( C ) C達到經(jīng)濟效果 8、提高軸心受壓構件局部穩(wěn)定常用

8、的合理方法是(D ) D設置橫向加勁肋9、為提高軸心受壓構件的整體穩(wěn)定,在構件截面面積不變的情況下,構件截面的形式應使其面積分布( B )。 B 盡可能遠離形心 10、軸心受壓構件發(fā)生彈性失穩(wěn)時,截面上的平均應力( C )。 C 低于鋼材比例極限11、軸心受壓構件柱腳底板的面積主要取決于( C )C基礎材料的抗壓能力12、兩端鉸接的理想軸心受壓構件,當截面形式為雙軸對稱十字形時,在軸心壓力作用下構件可能發(fā)生(C)。C扭轉屈曲 13、在下列關于柱腳底板厚度的說法中,錯誤的是( C )C 其它條件相同時,四邊支承板應比三邊支承板更厚些14、下列軸心受拉構件,可不驗算正常使用極限狀態(tài)的是 (D)D

9、預應力拉桿15、雙肢格構式受壓柱,實軸為xx,虛軸為yy,應根據(jù)( B )確定肢件間距離。B 16、承受橫向荷載的構件稱為( A )A 受彎構件 17、鋼梁彎曲應力的發(fā)展三個階段分別是( A )A彈性工作階段、彈塑性工作階段、塑性工作階段18、提高腹板的穩(wěn)定性,相對比較經(jīng)濟的措施是( A )A增大腹板面積19、梁的撓度驗算其實是( C )C驗算梁的剛度20、計算工字形截面梁的抗彎強度采用公式,取=105,梁的受壓翼緣外伸肢寬厚比不大于( B )A B 1、驗算工字形截面梁的折算應力的公式,式中、應為( D )D驗算截面中驗算點的正應力和剪應力2、不考慮腹板屈曲后強度,工字形截面梁腹板高厚比=1

10、00時,梁腹板可能( D )D因剪應力引起屈曲,需設橫向加勁肋3、梁上作用較大固定集中荷載時,其作用點處應( B )。B 設置支承加勁肋4、焊接工字形截面梁腹板設置加勁肋的目的是( D )。D 提高梁的局部穩(wěn)定性5、保證工字形截面梁受壓翼緣局部穩(wěn)定的方法是( D )D限制其寬厚比6、對于承受均布荷載的熱軋H型鋼簡支梁,應計算( D )D抗彎強度、抗剪強度、整體穩(wěn)定、撓度7、一簡支箱形截面梁,跨度60m,梁寬1m,梁高36m,鋼材為16Mn,在垂直荷栽作用下,梁的整體穩(wěn)定系數(shù)為( D )D1008、在焊接組合梁的設計中,腹板厚度應( C )。C 厚薄相當D 厚薄無所謂9、在焊接工字形組合梁中,翼

11、緣與腹板連接的角焊縫計算長度不受的限制,是因為( D )。D 內力沿側面角焊縫全長分布的關系10、工字形截面梁受壓翼緣,對Q235鋼,保證局部穩(wěn)定的寬厚比限值為,對Q345鋼,此寬厚比限值應為( A )A比15更小 11、為了提高梁的整體穩(wěn)定,最經(jīng)濟有效的辦法是(B)B 增加側向支撐點 12、當無集中荷載作用時,焊接工字形截面梁翼緣與腹板的焊縫主要承受( C )。C 水平剪力13、圖1所示為加強受壓翼緣的工字形等截面簡支組合梁,抗側移支撐桿設置對提高梁的整體穩(wěn)定性效果最好。(A)圖114、單軸對稱的實腹式壓彎構件整體穩(wěn)定性計算公式和中的、說法正確的是( D )D和為單軸對稱截面繞非對稱軸較大和

12、較小翼緣最外纖維的毛截面模量,值相同15、有側移的單層鋼框架,采用等截面柱,柱與基礎固接,與橫梁鉸接,框架平面內柱的計算長度系數(shù)為( A )A203 16、單軸對稱截面的壓彎構件,當彎矩作用在對稱軸平面內,且使較大翼緣受壓時,構件達到臨界狀態(tài)的應力分布說法正確的是( A )A 可能在拉、壓側都出現(xiàn)塑性 17、實腹式偏心受壓構件在彎矩作用平面內整體穩(wěn)定驗算公式中的主要是考慮 ( A )。A 截面塑性發(fā)展對承載力的影響 18、單軸對稱截面的壓彎構件,一般宜使彎矩( A )A繞非對稱軸作用 19、計算格構式壓彎構件的綴材時,剪力應取( C )。C 構件實際剪力設計值或由公式計算的剪力兩者中較大值20

13、、關于屋架的形式說法有誤的一項是( B )B 屋架外形選擇最重要的方面是用料經(jīng)濟,其次是建筑物用途 二、判斷題1鋼結構在涂刷油漆前應徹底除銹,油漆質量和涂層厚度均應符合相關規(guī)范要求。()2正常使用極限狀態(tài)包括構件和連接的強度破壞、疲勞破壞和因過度變形而不適于繼續(xù)承載,結構和構件喪失穩(wěn)定,結構轉變?yōu)闄C動體系和結構傾覆。()3輕鋼結構主要包括鋼-混凝土組合梁和鋼管混凝土柱等。()4鋼結構計算的目的在于保證所設計的結構和構件滿足預期的各種功能。()5用作鋼結構的鋼材必須具有較高的強度、足夠的變形能力和良好的工藝性能。()6鋼材在單向受壓(粗而短的試件)時,受力性能基本和單向受拉時相同。()7鋼筋的冷

14、彎試驗是按照有關規(guī)定的彎心直徑在試驗機上采用沖頭加壓,使試件完成45,如試件外表面不出現(xiàn)裂紋和分層,即為合格。()8碳含量在0.120.20范圍內碳素鋼,可焊性好。()9實踐證明,構件的壓力水平越低,越容易發(fā)生疲勞破壞。()10槽鋼分為普通槽鋼和輕型槽鋼,其編號的依據(jù)是其截面寬度(單位m)。()1、鋼結構的連接就是把板材或型鋼組合成構件,再將構件組合成結構,以保證結構的共同受力。( )2、側面角焊縫主要承受剪力、塑性較差、但彈性模量較高,強度也高。( )3、采用角焊縫連接的板件必須坡口,焊縫金屬不可直接充填在由被連接板件形成的直角或斜角區(qū)域內。( )4、焊縫的連接形式按被連接板件的相互位置可分

15、為對接、搭接、T型連接和角部連接四種形式。( )5、在荷載作用下,如果焊縫長度適宜,當焊縫兩端點處的應力達到屈服強度后,繼續(xù)加載,應力會逐漸均勻。( )6、焊接冷卻后產生的變形稱為焊接殘余變形,這時焊件中的應力稱為焊接殘余應力。( )7、9螺栓錯列排列比較簡單整齊,布置緊湊,所用連接板尺寸小,但對構件截面的削弱較大。( )8、普通螺栓連接的抗剪承載力,應考慮螺栓桿受剪和孔壁承壓兩種情況。( )9、高強度螺栓連接時的摩擦力隨外力增大而增大,接近破壞時,與桿身共同承擔剪力。( )10、高強度螺栓群在扭矩或扭矩、剪力共同作用時的剪力計算方法與普通螺栓群完全不同,其應采用高強度螺栓承載力的極限值進行計

16、算。( ) 1、軸心受力構件包括軸心受拉構件和軸心受壓構件。( ) 2、軸心受力構件的強度制其長細比來保證。( ) 3、單軸對稱截面構件繞對稱軸屈曲時,在發(fā)生彎曲變形的同時絕對不發(fā)生扭轉。()4、殘余應力對軸心受壓構件承載力的影響,主要考慮縱向殘余應力。( )5、具有初始彎曲的壓桿,壓力一開始作用,桿件就產生撓曲,并隨著荷載的增大而增加。( )6、組成軸心受壓構件的板件過薄,在壓力作用下容易發(fā)生局部失穩(wěn)。( )7、實腹式軸心受壓構件一般采用單軸對稱截面來避免彎曲失穩(wěn)。( )8、格構式構件軸心受壓構件撓實軸的穩(wěn)定性計算與實腹式軸心受壓構件相同。( )9、軸心受壓柱的柱頭構造應使柱身的內力可靠地傳

17、給基礎,并和基礎牢固地連接。( )10、組合梁相比型鋼梁加工簡單,成本較低,因而應優(yōu)先選用組合梁。( )1、梁主要用于承受彎矩,為了充分發(fā)揮材料的強度,其截面通常設計成高而窄的形式。()2、橫向荷載的臨界值僅與它自身大小有關,而與沿梁高的作用位置無關。()3、對于承受靜力荷載和間接承受動力荷載的組合梁,堅決不允許腹板在梁整體失調之前屈曲。()4、型鋼梁腹板和翼緣的寬厚比都比較小,局部穩(wěn)定??傻靡员WC,不需要進行驗算()5、鋼結構中主梁和次梁的連接形式一般有疊接和平接兩種。()6、同時承受軸向拉力或彎矩的構件稱為拉彎構件,同時承受軸向壓力或彎矩的構件稱為壓彎構件。()7、壓彎構件的受壓翼緣板,其

18、應力情況與梁受拉翼緣基本相同,因此其受壓翼緣寬厚比限梁受拉翼緣的寬厚比限制相同。()8、梁與柱的剛性連接要求連接節(jié)點不僅能可靠地傳遞剪力而且能有效地傳遞彎矩。()9、鋼材的切割有剪切、鋸切和氣割等方法,其中剪切機切割最復雜。()10、焊接鋼結構最費工的工序是制孔、裝配和打鉚。()三、簡答題1、鋼結構和其他材料的結構相比具有哪些特點?答:(1)建筑鋼材強度高,塑性和韌性好;(2)鋼結構的重量輕;(3)材質均勻,與力學計算的假定比較符合;(4)鋼結構制作簡便,施工工期短;(5)鋼結構密閉性好;(6)鋼結構耐腐蝕性差;(7)鋼材耐熱不耐火;(8)鋼結構可能發(fā)生脆性斷裂。2.鋼材“耐熱不耐火”的含義是

19、什么?規(guī)范對其有何規(guī)定?答:鋼材受熱,當溫度在200以內時,其主要力學性能,如屈服點和彈性模量降低不多。溫度超過200后,材質發(fā)生較大變化,不僅強度逐步降低,還會發(fā)生藍脆和徐變現(xiàn)象。溫度達600時,鋼材進入塑性狀態(tài)不能繼續(xù)承載。因此,鋼結構設計規(guī)范規(guī)定鋼材表面溫度超過150后即需加以隔熱防護,對需防火的結構,應按相關的規(guī)范采取防火保護措施。3、鋼結構設計必須滿足的功能包括哪些方面?答:(1)應能承受在正常施工和正常使用時可能出現(xiàn)的各種情況,包括荷載和溫度變化、基礎不均勻沉降以及地震作用等;(2)在正常使用情況下結構具有良好的工作性能;(3)在正常維護下結構具有足夠的耐久性;(4)在偶然事件發(fā)生

20、時及發(fā)生后仍能保持必需的整體穩(wěn)定性。4、時效硬化和人工時效各指什么?答:時效硬化:在高溫時熔化于鐵中的少量碳和氮,隨著時間的增長逐漸從純鐵中析出,形成自由碳化合物和氮化物,對純鐵體的塑性變形起遏制作用,從而使鋼材的強度提高,塑性、韌性下降,這種現(xiàn)象稱為時效硬化,俗稱老化。人工時效:時效硬化的過程一般很長,在材料塑性變形后加熱,可以使時效硬化發(fā)展特別迅速,這種方法稱為人工時效。5、什么情況下會產生應力集中,應力集中對鋼材性能有何影響?答:在鋼結構的構件中可能存在孔洞、槽口、凹角、截面突然改變以及鋼材內部缺陷等,使構件中的應力分布將不再保持均勻,而是在某些區(qū)域產生局部高峰應力,在另外一些區(qū)域則應力

21、降低,形成所謂應力集中現(xiàn)象。應力集中會使鋼材變脆的趨勢。6、簡述鋼材的疲勞破壞過程答:鋼材在反復荷載作用下,結構的抗力及性能都會發(fā)生重要變化,甚至發(fā)生疲勞破壞。根據(jù)試驗,在直接的連續(xù)反復的動力荷載作用下,鋼材的強度將降低,即低于一次靜力荷載作用下的拉伸試驗的極限強度,這種現(xiàn)象稱為鋼材的疲勞。疲勞破壞表現(xiàn)為突發(fā)的脆性斷裂。7、鋼材常見的冶金缺陷有哪些,各自的具體含義是什么?答:鋼材常見的冶金缺陷包括偏析、非金屬夾雜、氣孔、裂紋及分層等。偏析:是指鋼材中化學成分不一到和不均勻,特別是硫、磷偏析嚴重造成鋼材的性能惡化;非金屬夾雜:是指鋼中含有硫化物與氧化物等雜質;氣孔:是澆鑄鋼錠時,由氧化鐵與碳作用

22、所生成的一氧化碳氣體不能充分逸出而形成的。8簡述溫度對鋼材性能產生的影響。 答:鋼材性能隨溫度改變而有所變化,總的趨勢是溫度升高,鋼材強度降低,應變增大;反之溫度降低,鋼材強度會略有增加,同時鋼材會因塑性和韌性降低而變脆。1、鋼結構焊接連接方法的優(yōu)點和缺點有哪些?答:優(yōu)點(1)焊件間可以直接相連,構造簡單,制作加工方便;(2)不削弱截面,節(jié)省材料;(3)連接的密閉性好,結構的剛度大;(4)可實現(xiàn)自動化操作,提高焊接結構的質量。缺點(1)焊縫附近的熱影響區(qū)內,鋼材的金相組織發(fā)生改變,導致局部材質變脆;(2)焊接殘余應力和殘余變形使受壓構件承載力降低;(3)焊接結構對裂紋很敏感,局部裂紋一旦發(fā)生,

23、容易擴展至整個截面,低溫冷脆問題也較為突出。2、高強度螺栓的預拉力設計值P的計算公式中,系數(shù)的確定考慮了哪些因素?答:(1)擰緊螺栓時螺栓同時受到由預拉力引起的拉應力和由扭矩引起的扭轉剪應力作用;(2)施工時為了彌補高強度螺栓預拉應力的松弛損失,一般超張拉5%10%,為此考慮一個超張拉系數(shù)0.9;(3)考慮螺栓材質的不均勻性,引入一個折減系數(shù)0.9;(4)由于以螺栓的抗拉引吭高歌為準,為了安全引入一個安全系數(shù)0.9。3、抗剪普通螺栓有哪幾種可能的破壞形式?如何防止?答:破壞形式:(1)當螺栓桿直徑較小而板件較厚時,螺栓桿可能被剪斷;(2)當螺栓桿直徑較大、板件較薄時,板件可能被擠壞,由于螺栓桿

24、和板件的擠壓是相對的,故也把這種破壞叫做螺栓承壓破壞;(3)板件截面可能因螺栓孔削弱太多而被拉斷;(4)端距太小,端距范圍內的板件可能被螺栓桿沖剪破壞。防止:第(3)種破壞形式屬于構件的強度計算,第(4)種破壞形式通過限制螺栓端距大于或等于2d0加以避免。因此,抗剪螺栓連接計算只考慮第(1)、(2)種破壞形式。4、減少焊接應力和焊接變形的設計措施有哪些?答:(1)盡可能使焊縫對稱于構件截面的中性軸,以減少焊接變形;(2)采用適宜的焊腳尺寸和焊縫長度;(3)焊縫不宜過分集中(4)盡量避免兩條或三條焊縫垂直交叉(5)盡量避免在母材厚度方向的收縮應力。1、實腹式軸心受壓構件進行截面選擇時,應主要考慮

25、的原則是什么?答;(1)面積的分布應盡量開展,以增加截面的慣性矩和回轉半徑,提高柱的整體穩(wěn)定承載力和剛度;(2)兩個主軸方向盡量等穩(wěn)定,以達到經(jīng)濟的效果;(3)便于與其他構件進行連接,盡量能構造簡單,制造省工,取材方便。2、計算格構式軸心受壓構件繞軸的整體穩(wěn)定時,為什么采用換算長細比?答:對于格構式軸心受壓構件,當繞虛軸失穩(wěn)時,因肢件之間并不是連續(xù)的板而只是每隔一定距離用綴條或綴板聯(lián)系起來,構件的剪切變形較大,剪力造成的附加影響不能忽略,通常采用換算長細比來考慮綴材剪切變形對格構式軸心受壓構件繞虛軸的穩(wěn)定承載力的影響。3、簡述實腹式軸心受壓構件的設計步驟?答:(1)假定構件的長細比,求出需要的

26、截面面積A。(2)計算兩個主軸所需要的回轉半徑(3)由計算的截面面積A和兩個主回轉半徑優(yōu)先選用型鋼。(4)由所需要的A、h、b等,以及同時考慮構造要求、局部穩(wěn)定以及鋼材規(guī)格等,確定截面的初選尺寸。(5)構件強度、穩(wěn)定和剛度驗算4、鋼梁腹板計算高度如何取值?答:(1)軋制型鋼梁,為腹板在與上下翼緣相交接處兩內弧起點間的距離;(2)焊接組合梁,為腹板高度;(3)鉚接組合梁,為上下翼緣與腹板連接的鉚釘(或高強螺栓)線間最近距離。1、什么是梁的整體失穩(wěn)現(xiàn)象?答:梁主要用于承受彎矩,為了充分發(fā)揮材料的強度,其截面通常設計成高而窄的形式。荷載作用在最大剛度平面內。當荷載較小時,僅在彎矩作用平面內彎曲;當荷

27、載增大到某一數(shù)值后,梁在彎矩作用平面彎曲同時,將突然發(fā)生側向彎曲和扭轉,并喪失繼續(xù)承載的能力,這種現(xiàn)象稱為梁的彎扭屈曲或整體失穩(wěn)。2、根據(jù)彈性穩(wěn)定理論確定框架柱的計算長度時,都做了哪些假定?答:(1)框架只承受作用于節(jié)點的豎向荷載,忽略橫梁荷載和水平荷載產生梁端彎矩的影響;(2)所有框架柱同時喪失穩(wěn)定,即所有框架柱同時達到臨界荷載;(3)失穩(wěn)時橫梁兩端的轉角相等。3、實腹式壓彎構件截面選擇的具體步驟有哪些?答:(1)計算構件的內力設計值;即彎矩設計值MX、軸心壓力設計值N和剪力設計值V;(2)選擇截面形式;(3)確定鋼材及強度設計值;(4)確定彎矩作用平面內和平面外的計算長度;(5)根據(jù)經(jīng)驗或

28、已有資料初選截面尺寸;(6)對初選截面進行強度驗算、剛度驗算、彎矩作用平面內整體穩(wěn)定性驗算、彎矩作用平面外整體穩(wěn)定驗算和局部穩(wěn)定性驗算,如驗算不滿足要求,則對初選截面進行調整,重新計算,直至滿足要求。4、為什么要在桁架組成的屋蓋結構中設置支撐系統(tǒng),支撐系統(tǒng)具體作用體現(xiàn)在哪些方面?答:屋架在其自身平面內為幾何形狀不變體系并具有較大的剛度,能承受屋架平面內的各種荷載。但是,平面屋架本身在垂直于屋架平面的側向(屋架平面外)剛度和穩(wěn)定性則很差,不能承受水平荷載。因此,為使屋架結構有足夠的空間剛度和穩(wěn)定性,必須在屋架間設置支撐系統(tǒng)。保證結構的空間整體作用;避免壓桿側向失穩(wěn),防止拉桿產生過大的振動承擔和傳

29、遞水平荷載保證結構安裝時的穩(wěn)定與方便。四、計算題1.如圖所示:已知焊縫承受的斜向靜力荷載設計值kN,偏心e為30mm,角焊縫的焊腳尺寸,實際長度,鋼材為Q235B,焊條為E43型(=160N/mm2), 焊縫強度增大系數(shù)取122。驗算直角角焊縫的強度。圖1解:將F分解為垂直于焊縫和平行于焊縫的分力 直角角焊縫的強度滿足要求 2.如圖所示支柱上下端均為鉸接且設置支撐。支柱長度為9m,在兩個三分點處均有側向支撐,以阻止柱在弱軸方向的過早失穩(wěn)。構件的設計壓力為N250kN,容許長細比。支柱截面為工字形I20a,。鋼材為Q235()。驗算此支柱的整體穩(wěn)定和剛度。(截面撓x軸屬于a類截面,截面撓y軸屬于

30、b類截面)a類截面的整體穩(wěn)定系數(shù):01234567891100.5630.5550.5480.5410.5340.5270.5200.5140.5070.500b類截面的整體穩(wěn)定系數(shù):01234567891400.3450.3410.3370.3330.3290.3260.3220.3180.3150.311圖1解:先計算長細比, 計算得,取 根據(jù) 所以此柱的整體穩(wěn)定性和剛度均滿足要求。3.圖2所示簡支梁長6m,采用I36a(,),已知單位長度得質量為59.9kg/m,梁的自重為59.99.8587N/m,cm4,cm3,cm,mm。梁上作用恒荷載,荷載密度q=35000N/m,荷載分項系數(shù)1

31、.2,截面塑性發(fā)展系數(shù),。試驗算此梁的正應力及支座處剪應力。(13分)q圖2【解】:梁自重產生的彎矩為: Nm (2分) 外荷載在跨中產生的最大彎矩為: Nm (2分) 總彎矩為: Nm (1分) 驗算彎曲正應力: N/mm2215 N/mm2 (3分) 驗算支座處最大剪應力: 支座處剪力: V1/2 (3500065876 )1.2 128113.2 N (2分) 剪應力: 3N/mm2125 N/mm2 (3分)請您刪除一下內容,O(_)O謝謝!2016年中央電大期末復習考試小抄大全,電大期末考試必備小抄,電大考試必過小抄Basketball can make a true claim t

32、o being the only major sport that is an American invention. From high school to the professional level, basketball attracts a large following for live games as well as television coverage of events like the National Collegiate Athletic Association (NCAA) annual tournament and the National Basketball

33、 Association (NBA) and Womens National Basketball Association (WNBA) playoffs. And it has also made American heroes out of its player and coach legends like Michael Jordan, Larry Bird, Earvin Magic Johnson, Sheryl Swoopes, and other great players. At the heart of the game is the playing space and th

34、e equipment. The space is a rectangular, indoor court. The principal pieces of equipment are the two elevated baskets, one at each end (in the long direction) of the court, and the basketball itself. The ball is spherical in shape and is inflated. Basket-balls range in size from 28.5-30 in (72-76 cm

35、) in circumference, and in weight from 18-22 oz (510-624 g). For players below the high school level, a smaller ball is used, but the ball in mens games measures 29.5-30 in (75-76 cm) in circumference, and a womens ball is 28.5-29 in (72-74 cm) in circumference. The covering of the ball is leather,

36、rubber, composition, or synthetic, although leather covers only are dictated by rules for college play, unless the teams agree otherwise. Orange is the regulation color. At all levels of play, the home team provides the ball. Inflation of the ball is based on the height of the balls bounce. Inside t

37、he covering or casing, a rubber bladder holds air. The ball must be inflated to a pressure sufficient to make it rebound to a height (measured to the top of the ball) of 49-54 in (1.2-1.4 m) when it is dropped on a solid wooden floor from a starting height of 6 ft (1.80 m) measured from the bottom o

38、f the ball. The factory must test the balls, and the air pressure that makes the ball legal in keeping with the bounce test is stamped on the ball. During the intensity of high school and college tourneys and the professional playoffs, this inflated sphere commands considerable attention. Basketball

39、 is one of few sports with a known date of birth. On December 1, 1891, in Springfield, Massachusetts, James Naismith hung two half-bushel peach baskets at the opposite ends of a gymnasium and out-lined 13 rules based on five principles to his students at the International Training School of the Youn

40、g Mens Christian Association (YMCA), which later became Springfield College. Naismith (1861-1939) was a physical education teacher who was seeking a team sport with limited physical contact but a lot of running, jumping, shooting, and the hand-eye coordination required in handling a ball. The peach

41、baskets he hung as goals gave the sport the name of basketball. His students were excited about the game, and Christmas vacation gave them the chance to tell their friends and people at their local YMCAs about the game. The association leaders wrote to Naismith asking for copies of the rules, and th

42、ey were published in the Triangle, the school newspaper, on January 15,1892. Naismiths five basic principles center on the ball, which was described as large, light, and handled with the hands. Players could not move the ball by running alone, and none of the players was restricted against handling

43、the ball. The playing area was also open to all players, but there was to be no physical contact between players; the ball was the objective. To score, the ball had to be shot through a horizontal, elevated goal. The team with the most points at the end of an allotted time period wins. Early in the

44、history of basketball, the local YMCAs provided the gymnasiums, and membership in the organization grew rapidly. The size of the local gym dictated the number of players; smaller gyms used five players on a side, and the larger gyms allowed seven to nine. The team size became generally established a

45、s five in 1895, and, in 1897, this was made formal in the rules. The YMCA lost interest in supporting the game because 10-20 basketball players monopolized a gymnasium previously used by many more in a variety of activities. YMCA membership dropped, and basketball enthusiasts played in local halls.

46、This led to the building of basketball gymnasiums at schools and colleges and also to the formation of professional leagues. Although basketball was born in the United States, five of Naismiths original players were Canadians, and the game spread to Canada immediately. It was played in France by 189

47、3; England in 1894; Australia, China, and India between 1895 and 1900; and Japan in 1900. From 1891 through 1893, a soccer ball was used to play basketball. The first basketball was manufactured in 1894. It was 32 in (81 cm) in circumference, or about 4 in (10 cm) larger than a soccer ball. The dedi

48、cated basketball was made of laced leather and weighed less than 20 oz (567 g). The first molded ball that eliminated the need for laces was introduced in 1948; its construction and size of 30 in (76 cm) were ruled official in 1949. The rule-setters came from several groups early in the 1900s. Colle

49、ges and universities established their rules committees in 1905, the YMCA and the Amateur Athletic Union (AAU) created a set of rules jointly, state militia groups abided by a shared set of rules, and there were two professional sets of rules. A Joint Rules Committee for colleges, the AAU, and the Y

50、MCA was created in 1915, and, under the name the National Basketball Committee (NBC) made rules for amateur play until 1979. In that year, the National Federation of State High School Associations began governing the sport at the high school level, and the NCAA Rules Committee assumed rule-making re

51、sponsibilities for junior colleges, colleges, and the Armed Forces, with a similar committee holding jurisdiction over womens basketball. Until World War II, basketball became increasingly popular in the United States especially at the high school and college levels. After World War II, its populari

52、ty grew around the world. In the 1980s, interest in the game truly exploded because of television exposure. Broadcast of the NCAA Championship Games began in 1963, and, by the 1980s, cable television was carrying regular season college games and even high school championships in some states. Players

53、 like Bill Russell, Wilt Chamberlain, and Lew Alcindor (Kareem Abdul-Jabbar) became nationally famous at the college level and carried their fans along in their professional basketball careers. The womens game changed radically in 1971 when separate rules for women were modified to more closely rese

54、mble the mens game. Television interest followed the women as well with broadcast of NCAA championship tourneys beginning in the early 1980s and the formation of the WNBA in 1997. Internationally, Italy has probably become the leading basketball nation outside of the United States, with national, co

55、rporate, and professional teams. The Olympics boosts basketball internationally and has also spurred the womens game by recognizing it as an Olympic event in 1976. Again, television coverage of the Olympics has been exceptionally important in drawing attention to international teams. The first profe

56、ssional mens basketball league in the United States was the National Basketball League (NBL), which debuted in 1898. Players were paid on a per-game basis, and this league and others were hurt by the poor quality of games and the ever-changing players on a team. After the Great Depression, a new NBL

57、 was organized in 1937, and the Basketball Association of America was organized in 1946. The two leagues came to agree that players had to be assigned to teams on a contract basis and that high standards had to govern the game; under these premises, the two joined to form the National Basketball Ass

58、ociation (NBA) in 1949. A rival American Basketball Association (ABA) was inaugurated in 1967 and challenged the NBA for college talent and market share for almost ten years. In 1976, this league disbanded, but four of its teams remained as NBA teams. Unification came just in time for major televisi

59、on support. Several womens professional leagues were attempted and failed, including the Womens Professional Basketball League (WBL) and the Womens World Basketball Association, before the WNBA debuted in 1997 with the support of the NBA. James Naismith, originally from Al-monte, Ontario, invented b

60、asketball at the International YMCA Training School in Springfield, Massachusetts, in 1891. The game was first played with peach baskets (hence the name) and a soccer ball and was intended to provide indoor exercise for football players. As a result, it was originally a rough sport. Although ten of

61、Naismiths original thirteen rules remain, the game soon changed considerably, and the founder had little to do with its evolution. The first intercollegiate game was played in Minnesota in 1895, with nine players to a side and a final score of nine to three. A year later, the first five-man teams pl

62、ayed at the University of Chicago. Baskets were now constructed of twine nets but it was not until 1906 that the bottom of the nets were open. In 1897, the dribble was first used, field goals became two points, foul shots one point, and the first professional game was played. A year later, the first professional league was started, in the East, while in 1900, the first intercollegiate league began. In 1910, in

展開閱讀全文
溫馨提示:
1: 本站所有資源如無特殊說明,都需要本地電腦安裝OFFICE2007和PDF閱讀器。圖紙軟件為CAD,CAXA,PROE,UG,SolidWorks等.壓縮文件請下載最新的WinRAR軟件解壓。
2: 本站的文檔不包含任何第三方提供的附件圖紙等,如果需要附件,請聯(lián)系上傳者。文件的所有權益歸上傳用戶所有。
3.本站RAR壓縮包中若帶圖紙,網(wǎng)頁內容里面會有圖紙預覽,若沒有圖紙預覽就沒有圖紙。
4. 未經(jīng)權益所有人同意不得將文件中的內容挪作商業(yè)或盈利用途。
5. 裝配圖網(wǎng)僅提供信息存儲空間,僅對用戶上傳內容的表現(xiàn)方式做保護處理,對用戶上傳分享的文檔內容本身不做任何修改或編輯,并不能對任何下載內容負責。
6. 下載文件中如有侵權或不適當內容,請與我們聯(lián)系,我們立即糾正。
7. 本站不保證下載資源的準確性、安全性和完整性, 同時也不承擔用戶因使用這些下載資源對自己和他人造成任何形式的傷害或損失。

最新文檔

相關資源

更多
正為您匹配相似的精品文檔
關于我們 - 網(wǎng)站聲明 - 網(wǎng)站地圖 - 資源地圖 - 友情鏈接 - 網(wǎng)站客服 - 聯(lián)系我們

copyright@ 2023-2025  zhuangpeitu.com 裝配圖網(wǎng)版權所有   聯(lián)系電話:18123376007

備案號:ICP2024067431-1 川公網(wǎng)安備51140202000466號


本站為文檔C2C交易模式,即用戶上傳的文檔直接被用戶下載,本站只是中間服務平臺,本站所有文檔下載所得的收益歸上傳人(含作者)所有。裝配圖網(wǎng)僅提供信息存儲空間,僅對用戶上傳內容的表現(xiàn)方式做保護處理,對上載內容本身不做任何修改或編輯。若文檔所含內容侵犯了您的版權或隱私,請立即通知裝配圖網(wǎng),我們立即給予刪除!