1、 29 8 JOURNAL OFVIBRATION AND SHOCK Vo.l 29 No. 8 2010 N NZEl : 2009- 05- 18 l : 2009- 07- 31BT o, 1956 M11 3 (S9 S, 100013)K 1: N P e “ - - Ss %51Z_bs “ - N NZEi5,) sZET/ 4b 7Z N Y? p ZE , NSn?S, Es1C LilN, T V N L iy !a ! y !/ L ,#/ “ u # E4/ G b1oM:9 ; N ; ; Ems |: TB936 DS M : A N ! P1 p1 N Y,t+
2、 y N ! .4 l1 Lg( 10- 7 m /s2 ) e )1 pb M “ gEYy,MM VE ,V N L i u,V7F L i , P N C.1a aMa /a . ?T5,yN()aH (; )XY N e1oy b gEYL S vn L i N ! P? /Y,XS =E) ,i 1b7Z N ZE, VM1SEn?S/S/ $,SE/ “ u # E4b1 +S= X T| vBb Y aay() T 3# a.M # N Y J. F , 2008, 27( 1): 206- 214. 2 . 2 e.M .:/ T, 2001. 3,f. gEY N uY J.
3、My, 2004, 7: 79- 81. 4 ISO 8569: 1996, M echanical vibration and shock-M easurementand evaluation of shock and vibration effects on sensitive e-quipment in buildings S. 5 ISO 10811- 2: 2000, M echanical vibration and shock-V ibrationand shock in buildingsw ith sensitive equipment-Part2: Class-ificat
4、ion S. 6 Bessason B, M adshusC, FroysteinH A. V ibration criteria formetrology laboratories J. M eas. Sc.i Techno,l 1999, 10:1009- 1014. 7 FT, L ., ,. / M .:S, 2006, 296- 297. 8at,(1,I .EY 58 J., 2008, 28( 1): 38- 43. 9 ,u , .15Y N/ 5:gEY6 5) J. S/v( g S), 2007, 24( 4): 2- 8.216 2010 M29 Dynamicmode
5、lofmachinejointsbasedonstructuraldampingLID ing-shi, ZHANG Yi-du, WANG Peng( StateKey Laboratory ofV irtualReality Technology and Systems, School ofM echanicalEngineering and Automation, BeHi angUniversity, Beijing 100191, China)Abstract: The damping ofmachine joints, which is a structural damping,
6、results from joint surfaces rubbingw itheach other. A machine jointsmodelbased on structuraldamping was advanced. The dynamic characteristics ofmachinejointswere simulated by themodelw ith equivalent stiffness and structuraldamping. Experimentswereperformed to verifythe new mode.l Modal testing of t
7、he specimenwas carried outw ith thehelp ofDASP system. Theparameters of themodelwere identified based on thedata from complex eigenvalue analysis andmodal testing. The smallerrors between the resultsofFEM modelw ith the identified parameters and those of themodal testing show that themachine jointsm
8、odel is capableof describing the dynamic characteristics ofmachine jointswhen feasible parameters of themodel are set up.Keywords: structural damping; joints; finite elementmethod; complex eigenvalue analysis; modal testing(pp: 204- 208)Numericalstudyonenergyabsorptionofaluminum-compositehybridtubes
9、underaxialquas-istaticandimpactcrushingYUAN Pan, YANG Zhi-chun( SchoolofAeronautics, Northwestern PolytechnicalUniversity, Xipan 710072, China)Abstract: LS-DYNA explicit finite element codewas used to perform a numerical investigation on the energy ab-sorption behaviorof alum inum-composite square a
10、nd circular hybrid tubes under axial quas-istatic and impact crushing.The force-displacement curve, which describes the energy capability of the structure, was obtained. The finite elementmodelwas verified by comparing the numerical results of one squarehybrid tubew ith the experiment data from the
11、refer-ence paper under quas-i static crushing. Based on thismode,l parametric studywas conducted to determine the effect ofdifferentw inding thickness of compositematerialon energy absorption behavior of square and circular tubesw ith the sametube length, thickness and outer perimeter The results sh
12、ow that the cross-sectional configuration of hybrid tubes has agreat effecton energy absorption capability. More energy is absorbed by circularhybrid tubes than by squarehybrid tubesunder axialquas-i static crushing. The energy absorbed by impactcrushing isnotonly related to its energy absorption ca
13、pa-bility, but also affected by the impact intensity. It is necessary to control the stiffness of the hybrid tubes in thedesign ofcomposite thickness, avoiding reduction of energy absorption caused by hybrid tubes resilience.Keywords: composite structure; hybrid tube; quas-i static crushing; impact
14、crushing (pp: 209- 213)ResearchreviewonmeasurementandevaluationmethodsofenvironmentalvibrationforprecisioninstrumentsYUM ei(N ational Institute ofM etrology, Beijing 100013, China)Abstract: The existing problems aboutmeasurement and evaluation methods of environmental vibration for prec-ision instru
15、mentswere analyzed. Data analysismethods and technicaldifficulties about environmental vibration were dis-cussed. The paperpoints out that it isofgreat important significance and application value to deeply research on influencelaw of environmental vibration on precision instruments and to develop t
16、he evaluation standard and calibration specifica-tion. The research results provide the technicalbasis for site selection of precision instruments laboratory, vibration isola-tion device construction and vibration isolation technical implementation, and environmentalprotection and legislation forhigh and new technology concentrated regions.Keywords: metrology; environmentalvibration; precision instrumen;t allowed vibration limit value; environmentalprotection and legislation (pp: 214- 216)253Vo.l 29 No. 8 2010 JOURNAL OF VIBRATION AND SHOCK
