曹黎媛, 李春祥
(上海大學(xué) 土木工程系,上海 200072)
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基于剛度連接雙層調(diào)諧質(zhì)量阻尼器的性能
曹黎媛, 李春祥
(上海大學(xué) 土木工程系,上海200072)
提出了基于剛度連接的雙層調(diào)諧質(zhì)量阻尼器(SDTMD)裝置。SDTMD是在雙層調(diào)諧質(zhì)量阻尼器(DTMD)的基礎(chǔ)上,在主體結(jié)構(gòu)與小質(zhì)量塊之間設(shè)置一個(gè)附加彈簧而構(gòu)成。經(jīng)定義SDTMD最優(yōu)參數(shù)的評(píng)價(jià)準(zhǔn)則,在頻域內(nèi)研究了質(zhì)量比對(duì)SDTMD控制結(jié)構(gòu)位移響應(yīng)時(shí)最優(yōu)參數(shù)和有效性以及沖程的影響;并與TMD、DTMD和基于阻尼連接雙層調(diào)諧質(zhì)量阻尼器(DDTMD)裝置進(jìn)行了比較。數(shù)值結(jié)果表明,SDTMD的控制有效性明顯高于TMD、DTMD和DDTMD。
結(jié)構(gòu)振動(dòng)控制;基于剛度連接雙層調(diào)諧質(zhì)量阻尼器;優(yōu)化;性能;地震
調(diào)諧質(zhì)量阻尼器(Tuned Mass Damper, TMD)是一種有效的被動(dòng)控制裝置。TMD通過準(zhǔn)確調(diào)整自身系統(tǒng)的頻率和阻尼,將主結(jié)構(gòu)振動(dòng)系統(tǒng)的能量轉(zhuǎn)移到TMD并由其耗散,從而抑制主結(jié)構(gòu)的振動(dòng)響應(yīng)。TMD研究起源于1928年,Ormondroyd等[1]提出了動(dòng)力吸振器思想。此后,TMD在工業(yè)界得到了迅速發(fā)展和應(yīng)用。1977年,美國(guó)波士頓Hancock大廈和紐約花旗中心大樓先后安裝了TMD,隨后TMD開始應(yīng)用于土木工程結(jié)構(gòu)的振動(dòng)控制。然而,在實(shí)際應(yīng)用中,由于TMD的頻率很難達(dá)到預(yù)期的最優(yōu)調(diào)諧狀態(tài),因而其控制結(jié)構(gòu)地震響應(yīng)的有效性不高或不穩(wěn)定。為改善TMD對(duì)結(jié)構(gòu)振動(dòng)控制的有效性和魯棒性,Igusa和Xu[2]提出了采用不同頻率的多重TMD(MTMD)概念;此后,眾多學(xué)者對(duì)MTMD展開了深入的研究[3-7]。李春祥在MTMD的研究基礎(chǔ)上,提出了雙層調(diào)諧質(zhì)量阻尼器(DTMD)[8]、基于剛度-阻尼器主動(dòng)調(diào)諧質(zhì)量阻尼器(SD-ATMD)[9]和基于剛度-阻尼器主動(dòng)多重調(diào)諧質(zhì)量阻尼器(SD-AMTMD)[10]等控制裝置。DTMD具有與MTMD相當(dāng)?shù)膬?yōu)越性;而SD-ATMD和SD-AMTMD有效性近似達(dá)到ATMD和AMTMD有效性,但它們的最優(yōu)調(diào)諧頻率比和平均阻尼比有明顯的變化。本文與上述不同的是:在主體結(jié)構(gòu)與DTMD的小質(zhì)量塊之間設(shè)置一個(gè)附加彈簧,構(gòu)成SDTMD新裝置,以期進(jìn)一步提升DTMD的有效性。
結(jié)構(gòu)-SDTMD系統(tǒng)的力學(xué)模型如圖1(a)所示。
結(jié)構(gòu)-SDTMD系統(tǒng)的動(dòng)力方程可表示為:
(1)
(2)
(3)
圖1(a) 基于剛度連接的雙層調(diào)諧質(zhì)量阻尼器Fig.1(a) Stiffness-connection based DTMD
圖1(b) 基于阻尼連接的雙層調(diào)諧質(zhì)量阻尼器Fig.1(b) damping-connection based DTMD
式中:ξs為主結(jié)構(gòu)的阻尼比;ξT為TMD1的阻尼比;ξt為TMD2的阻尼比;μT為TMD1與主結(jié)構(gòu)的質(zhì)量比;μt為TMD2與主結(jié)構(gòu)的質(zhì)量比;η為TMD2與TMD1的質(zhì)量比。
(4)
(5)
(6)
分別定義結(jié)構(gòu)-SDTMD系統(tǒng)位移(ys)、TMD1沖程(yT)和TMD2沖程(yt)的動(dòng)力放大系數(shù):
(9)
式中:
ReT(λ)=D11Re(λ)-D12Im(λ)
ImT(λ)=D12Re(λ)+D11Im(λ)
Ret(λ)=D21Re(λ)-D22Im(λ)
Imt(λ)=D22Re(λ)+D21Im(λ)
C12=-2(1+η)ξtftλ
RHs=min.max.(DMFHs)
(10)
式(10)表示:使用GA算法,得到目標(biāo)函數(shù)(式7)中位移動(dòng)力放大系數(shù)DMFHs的最大值,在參數(shù)(fT、ft、fL、ξT和ξt)范圍內(nèi),使最大DMFHs的最小化,從而獲得最優(yōu)的參數(shù)。
根據(jù)SDTMD的最優(yōu)參數(shù)評(píng)價(jià)準(zhǔn)則,使用遺傳算法(GA),對(duì)SDTMD的性能進(jìn)行數(shù)值分析。為比較,同時(shí)給出了TMD、DTMD(力學(xué)模型見文獻(xiàn)[8])、DDTMD(力學(xué)模型如圖1(b)所示)的數(shù)值結(jié)果。設(shè)fT=0.5~1.7,ft=0.0~1.4,fL=0.0~1.4,ξT=0~0.999,ξt=0~0.999,ξL=0~0.999,ΔfT=0.001,Δft=0.001,ΔfL=0.001,ΔξT=0.001,Δξt=0.001,ΔξL=0.001,λ=0~2,使用GA,得到μT=0.01和μT=0.02,η分別取0.25、0.5、0.75、1.0時(shí),DMFHs、DMFHT、DMFHt、fT、ft、fL、ξT、ξt隨η的變化曲線(圖2-9)。因TMD僅有一個(gè)附加質(zhì)量,為便于對(duì)比并確保與SDTMD的附加總質(zhì)量保持一致,對(duì)應(yīng)于SDTMD在不同μT取值時(shí)的η變化情況,將TMD取μT值分別修正為0.012 5、0.015、0.017 5、0.02與0.025、0.03、0.035、0.04。
由圖2知,對(duì)結(jié)構(gòu)—SDTMD系統(tǒng),結(jié)構(gòu)位移動(dòng)力放大系數(shù)DMFHs隨η增大而減小,意味著有效性越來越好。但當(dāng)η>0.5時(shí),總體上,增大η時(shí)SDTMD的控制有效性提高不明顯。
由圖3~4知,大質(zhì)量塊沖程DMFHT隨η增大而減小。相對(duì)TMD、DTMD、DDTMD,SDTMD的大質(zhì)量塊沖程DMFHT有所減??;而小質(zhì)量塊沖程DMFHt則明顯增大,這也是SDTMD有效性明顯提高的原因。由μT=0.01和μT=0.02兩種情況可看出,SDTMD小質(zhì)量塊沖程比大質(zhì)量塊沖程大;但實(shí)際中,η一般只采用0.5,所以SDTMD小質(zhì)量塊沖程是完全可以接受的。
圖2 μT=0.01,0.02時(shí)TMD、DTMD、DDTMD、SDTMD的DMFHs隨η變化趨勢(shì)Fig.2 Variation trend ofDMFHswith respect to η for TMD, DTMD, DDTMD, and SDTMD in the case of μT=0.01,0.02
圖3 μT=0.01,0.02時(shí)TMD、DTMD、DDTMD、SDTMD的DMFHT隨η變化趨勢(shì)Fig.3 Variation trend of DMFHTwith respect to η for TMD, DTMD, DDTMD, and SDTMD in the case of μT=0.01,0.02
圖4 μT=0.01,0.02時(shí)DTMD、DDTMD、SDTMD的DMFHt隨η變化趨勢(shì)Fig.4 Variation trend of DMFHtwith respect to η for DTMD,DDTMD and SDTMD in the case of μT=0.01,0.02
圖5 μT=0.01,0.02時(shí)TMD、DTMD、SDTMD的fT隨η變化趨勢(shì)Fig.5 Variation trend of fT with respect to η for TMD,DTMD and SDTMD in the case of μT=0.01,0.02
圖6 μT=0.01,0.02時(shí)DTMD和SDTMD的ft隨η變化趨勢(shì)Fig.6 Variation trend of ft with respect to η for TMD,DTMD and SDTMD in the case of μT=0.01,0.02
圖7 μT=0.01,0.02時(shí)TMD、DTMD、SDTMD的ξT隨η變化趨勢(shì)Fig.7 Variation trend of ξT with respect to η for TMD,DTMD and SDTMD in the case of μT=0.01,0.02
由圖5和圖6知,當(dāng)μT=0.01時(shí),SDTMD的頻率比fT隨η的增大而增大,但不明顯,在1.0~1.1之間取值;SDTMD的頻率比fT略高于DTMD的,且明顯小于TMD的。當(dāng)μT=0.02時(shí),SDTMD的頻率比fT隨η的增大而減小,變化相對(duì)較明顯,取值范圍為0.6~1.0;SDTMD的頻率fT明顯小于TMD和DTMD的。對(duì)于μT=0.01情況,SDTMD的頻率比ft隨η的增大而減??;當(dāng)η>0.5時(shí),增大η,ft變化不明顯,取值范圍為0.2~0.6。對(duì)于μT=0.02情況,SDTMD的頻率比ft隨η的增大而減小,總體變化不明顯,取值范圍為0.1~0.15。SDTMD的頻率比明顯小于DTMD的頻率比。
由圖7和圖8知,μT=0.01時(shí),SDTMD阻尼比ξT為0;μT=0.02時(shí),SDTMD阻尼比ξT隨η的增大而增大;當(dāng)η>0.75時(shí),SDTMD阻尼比超過了TMD,取值范圍為0.06~0.14。對(duì)于μT=0.01,SDTMD阻尼比ξt隨η的增大而增大,但明顯小于DTMD阻尼比,取值范圍為0.2~0.4;對(duì)于μT=0.02,SDTMD阻尼比ξt趨近于0,且明顯小于DTMD阻尼比。
圖8 μT=0.01,0.02時(shí)DTMD、SDTMD的ξt隨η變化趨勢(shì)Fig.8 Variation trend of ξt with respect to η for DTMD and SDTMD in the case of μT=0.01,0.02
由圖9知,μT=0.01時(shí),SDTMD頻率比fL隨η的增大而增大;當(dāng)η>0.75時(shí),fL隨η的增大而減小,但變化不明顯,取值范圍為0.68~0.76。μT=0.02時(shí),SDTMD頻率比fL隨η的增大而增大,取值范圍1.02~1.06。
考慮到SDTMD控制的有效性、沖程以及參數(shù)的經(jīng)濟(jì)合理性這三個(gè)因素,經(jīng)綜合比較圖2-9,本文建議選擇表1中A和B兩組數(shù)據(jù)。根據(jù)這2組參數(shù)設(shè)計(jì)的SDTMD,其控制有效性明顯好于TMD和DTMD,而且參數(shù)和沖程都在合理、可接受的范圍內(nèi)。
圖9 μT=0.01,0.02時(shí)SDTMD的fL隨η變化關(guān)系曲線Fig.9 Variation trend of fL with respect to η for DTMD and SDTMD in the case of μT=0.01,0.02
組號(hào)ηfTftfLξTξtDMFHsDMFHTDMFHtA0.251.0190.5680.69700.2357.190146.588282.9357B0.51.0210.4290.75100.2196.536939.857473.2892
本文提出了基于剛度連接的雙層調(diào)諧質(zhì)量阻尼器(SDTMD)裝置。通過推導(dǎo)及定義的SDTMD最優(yōu)參數(shù)評(píng)價(jià)準(zhǔn)則,使用遺傳算法(GA)優(yōu)化,在頻域內(nèi)數(shù)值研究了SDTMD的最優(yōu)控制性能,并與TMD、DTMD、DDTMD進(jìn)行了比較。數(shù)值結(jié)果表明,①SDTMD的有效性明顯高于TMD、DTMD、DDTMD。②在實(shí)際中,建議η采用0.25或0.5,所以SDTMD小質(zhì)量塊沖程是完全可以接受的。③SDTMD最優(yōu)頻率比fT和ft都明顯小于TMD、DTMD的相應(yīng)值;而且μT=0.01時(shí),fT在1.0~1.1和ft在0.2~0.6之間比較合適。④μT=0.01時(shí),SDTMD的大質(zhì)量塊阻尼比為0,因此可以進(jìn)一步簡(jiǎn)化裝置。⑤隨著質(zhì)量比η的增加,SDTMD最優(yōu)頻率比fL存在極大值。此外,論文給出了SDTMD的最優(yōu)設(shè)計(jì)參數(shù)表格,供設(shè)計(jì)時(shí)選擇。
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Double-tuned-mass dampers based on stiffness connection
CAO Liyuan, LI Chunxiang
(Department of Civil Engineering, Shanghai University, Shanghai 200072, China)
Stiffness-connection-based double-tuned-mass dampers(SDTMD) were proposed here. Specifically, an added stiffness between the controlled structure and the smaller mass block in a DTMD was introduced to form a SDTMD. In order to obtain optimal parameters of SDTMD, an optimal criterion was defined. Employing this defined criterion, the influences of mass ratio on optimal parameters, effectiveness and stroke of SDTMD were studied numerically in frequency domain. Furthermore, the optimal performances of SDTMD were compared with those of TMD, DTMD, and damping-connection-based double-tuned-mass dampers(DDTMD). The numerical results showed that the effectiveness of SDTMD is remarkably higher than those of TMD, DTMD and DDTMD.
structural vibration control; stiffness-connection-based double-tuned-mass dampers(SDTMD); optimization; performance; earthquake
2015-05-19修改稿收到日期:2015-08-10
曹黎媛 女,研究生,1991年4月生
李春祥 男,博士,教授,博士生導(dǎo)師,1964年12月生
TU311
A
10.13465/j.cnki.jvs.2016.15.029