结构力学第三版王焕定第3章习题及参考答案

2-1AbTSRQPONLKJIHGFECl=6aDBaMa2FpFpFpaFpHGFECFpDBAFpdcHGFEDDCBAFpQAVUTSRPONMLKJIHGFDCBaal=8aFpFpEFp(a)ABBCCDDEDFFGGH7(b)ACFGEBLMIDJDNGCHPONRKELTSRGOGHHOSKKLSLOHGGOGHHO12(c)ANNOOJOPJBJCKCKQKDERSLLFLGGMMUMHTUUVVI19(d)BCEGDACCDCFFDFGGDGHDEDB9课后答案网(a)10123456789111213010kN40kN21.25m42.5m32.5kN17.5kNN12N130,0FF==FN4FN5FN1FN1FN817.5kNα10kNFN2FN9ααFN432.5kNαFN1040kNFN3αα(d)(c)(b)(a)(e)FN11FN3αFN21.2512tan0.5sincos2.555αα====α0yF=∑N117.5kN/sin17.55kN=39.13kNFα=−=−−0xF=∑N817.5kN/tan35kNFα==N7N835kNFF==N9N9sin210kNcos0,55kN=11.18kNFFαα+×==−−12N2N1N2()sin210kNcos0,12.55kN=27.95kNFFFαα−−×==−−0yF=∑N432.5kN/sin32.55kN=72.67kNFα=−=−−0xF=∑N532.5kN/tan65kNFα==N6N565kNFF==(b)N10N10sin240kNcos0,205kN=44.72kNFFαα+×==−−N3N4N3N4()sin240kNcos0,20kN/sin=27.951kNFFFFααα−−×==+−(e)0yF=∑N11N2N3()sin25FFFkNα=−+=课后答案网(b)cFN4FN5βαθFN3FN6FN4bFN1FN2αθβFN3aFp1221344355664m2m2m4m3m3mFpFpFN2FN1αβ12sincos55αα==23sincos1313ββ==34sincos55θθ==(a)N1N2PN1N2cossin0sincos0FFFFFβαβ++=+α=N1P1.8028FF=−N2P1.1180FF=(b)N4N2N1N4Pcoscossi02.5nFFFFFθαβ=−+−=N3N4N3N2N1Psinsincos0.50FFFFFFθαβ+−−==(c)N6N5N4N6N5N4cossincos0sincossin0FFFFFFβαθβαθ−+=+−=N5P1.9566FF=−N6P1.3521FF=2-31AB0,0yBMF==∑∑2.5AyByPFFF==21340yF=∑N3P22FF=0KM=∑N1P4FF=0xF=∑N4P4.5FF=−FN1FpFpFN22.5Fp2.5FpFpFp2FN4FN3FN1K3230=∑yFN2P0.5FF=−课后答案网=∑ByF=0yF=∑AyF=N8kNIDF=−0yF=∑FN2FNJKLKBFGFNEF15.33kNIDN15.6F=42kN=6kNFBy2JKEF0yF=∑N2528.33kNByFF==课后答案网====−5/4sin,5/3cos==θθAFN1AθFN3FN2FN3BN3N15=33.33kN3FF=−FN4N2N14=26.67kN3FF=−20kNBN426.67kNF=课后答案网(a)(a)80kN245oFN180kNFN2KFN1(b)(a)0xF=∑N1N1cos4580kN0,802kN=113.12kNFF−==D(b)K0KM=∑N2N1N22m+sin452m0=80kNFFF×××=−D2-6b23aFN2FpFp1FN445oFN345oFN2K0Fp045oFN2FN345oFN3FN4FN13.5Fp(c)(a)(b)N2PN2P2+cos450=2FFFF×=−DbN3N2PPN3P0sin45sin453.5202yFFFFFF=−−+==∑DDF4N4N3PPN4P02cos4523.520KMFdFdFdFdF=×+×+×−×=∑DF=−134cFN1N1N3N1Psin450,FFFF+==D−2-6(c)123430kN42m32m12330kN30kN12330kN30kN30kN30kN430kN(b)(a)(a)123N130kNF=N2302kN=42.42kNF=−N3152kN=21.21kNF=−−课后答案网==−∑bFpFpFN1FN3AFpFN2Fp0N200yFF==∑(a)(b)2-6(e)N100FF==x∑12N20F=2-6(f)abFN1FpG0FpFp21FpFpFp2FN3FN4FN5ABCDEFHHFDCDFN2FN5FN5Fp45oαAFN1Fp(a)(c)(d)(b)PN5PN50303HFMFdFdF=×−×==∑(c)1sin5α=N2N5N2N5P50sin053xFFFFFα−=+==−=∑F(d)N1N5N1N5P20cos45023xFFFFF−=+==−=∑DF课后答案网=N25kNF=−4m4m5kN15kN214m15kN10kNbFN3FN1FN210kN5kN4m4m4m10kN5kNa课后答案网=∑0,152AyyFF==∑48kN=kNBCH0,130kNCBxMFF===∑0,F132kN()AxxF==∑22204()/3m25202tan0.4sin0.37139067425cos0.928476691xxyfxlxlxθθθ−=−==−====FHFAy20kN/mFNFQKθ3mM5mH05m3m100kN2.5m0120kNmKAyMMFFM=−×+×+×==⋅∑KQHNH100kNcoscossin0,0.26kN100kNsinsincos0,140.14kNAyAyFFFFFFFFQNθθθθθθ+×−+==+×−−==课后答案网·m1.67kN·m17.5kN·m3.75kN·m课后答案网·m40kN30kN80kN·m60kN·m60kN·m课后答案网(a)(b)(c)FpFpq(d)(e)(f)000000课后答案网(2)8qlxM−=22(2)()222qlxxqxqlxxM−−=+=12MM=2(2)()82qlxqlxx−−=22(2)4()880lxlxxxlxl−=−−+=2x0.5l86432220.1464164xll−−−===llx1464.0=课后答案网(a)77.6kN20kN80kN140kN19.4kN140kN150kN·m160kN·m10kN·m10kN·m0kN140kN2-12(b)20kN60kN40kN20kN20kN60kN60kN80kN·m80kN·m80kN·m40kN·m40kN20kN60kN课后答案网·m260kN·m7.5kN72.5kN7.5kN7.5kN20kN7.5kN7.5kN20kN课后答案网(b)(a)Fpl/2FplFpll/2l/2l4m8864m2m2m(kN·m88kN·m2kN1kNFp2Fp课后答案网(a)(b)(c)1030(a)(b)(c)7070MkN·m18020200200200150150MkN·mMMMkN·mMkN·m(e)(d)10MkN·m3010303030640540220220801010202020104040408080100100MkN·mMkN·m(g)(f)(d)(e)(f)(g)课后答案网(i)150kN(h)MkN·m150kN200kN6008002006004m320520MkN·m440(h)(i)课后答案网(a)(b)3Fp(a)(b)M3Fp3Fp18MkN·m189(c)16032002560320kN(d)32040kN40kNMkN·m160kN3204040160640kNMkN·m(c)(d)16040kN16040kNMkN·m(f)1606060404016060(e)40kN80kNMkN·m80801208040kN(e)(d)课后答案网·m40255025(g)(h)600MkN·m(g)(h)M2ql2/32ql2/3ql2/82ql2/3M*FplMkN·m0.750.250.250.500.750.500.250.250.2512161612(k)(j)(i)(i)(j)(k)课后答案网(a)27.27kN75kN75kN27.27kNMkN·m75kN67543218.2218.2128975kNkNFN45=+25kNFN14=-106.1kNFN24=+25kNFN34=-72.7kNFN12=-25kN12345678927.2772.772.772.772.775kN75kNFN25=-35.4kNkN2-16(b)21.6kN-24kN21.6kN4.5kN·mMFN0kN13.4kNNN-24k0kN13.4k4.5kN·m330kN33(b)kN课后答案网(a)120kN480320404040kN240kN240kN120kN120kNMkN·m339.4-240339.4240240240-240kN2-17(b)2060-6020MkN·m2400kN20kN80kN24016040kN课后答案网