复合多层混合结构三维热传导分析_常晓权_图文_百度文库

1、 CH I N ESE JOURNAL OF APPL IED M ECHAN ICS V o. l 22 Torsion in Spot -W elded Thin W alled Box w ith V arying Section P eiX ingzhu 1 R en Zhengquan 2 Z hang L i 1 ( S chool of C ivil Engineering and M ech an ics , X ia 'n Jiaotong U n iversity, X ia 'n 710049 , Ch in a 1 ( C ollege of S cie

2、n ce and Eng ineering, Y anb ian U n iversity , Y an ji 133002, Ch ina 2 Abstract : A m ethod to analyze torsion perfor m ances in a spot we ld ed thin-w alled box is proposed , where th e cross sect ion varies slow ly along the long itud ina l d irect ion. W arp ing torsions for tw o situatio ns, e

3、ven and uneven pitch o f spot w elds, are d iscussed . It is concluded that torsion rig id ity is w eakened as the beam length increases , whose de creasing rate is nearly equal to one o f unifor m section ; the beam w ith varying sect ion keeps a certain rig idity w ith fe w er w elding spots and l

4、ow er cos. t If the we ld ed spot pitch p 2, in the rig h, t variesw ith in 25 % of the pitch p 1 in the left , the shearing force transm ission nearly unvaries. T he si m u latio n results co in cide the experi m ental ones very w el.l Keywords: varying section, spot-w elded thinw alled box section

5、 beam, w arp ing torsion, w elded spo t p itch. Chaotic Identification toW eak Signals of Automobile L i X iang lian ( Phys ics Exp eri m en t Cen ter , N an jing U n iversity of A eronaut ics and A s tronau tics , N an jing, 210016 Abstract : T he chaot ic osc illator is va lu able for w eak signa

6、l detect io n , The correspond ing theory is in troduced and th e adapt iv e ad ju stm ent m ethod conjo in ed the a m plitude w ith frequency is e m p lo yed to ident ify the w eak sig na ls . The si m ulat ion analysis w ith chaotic detectio n for w eak period ic sig nals subm erged in v io lent n

7、o ise is carried ou. t For a cracked flywheel shell in au tom obile , the real w eak v ib ration signal id entificatio n is ach ieved . A com parison w ith the co rre la tiv e stud ie s ind icates the valid ity of th is m ethod in autom ob ile part fau lt analysis . Keywords: chaos , w eak sig nal,

8、vibra tion, id entif ication, detection. Three -D i m ensional H eat Transfer Analysis to H ybrid M ultilayer Co m posite Structure Chang X iaoquan Zheng Gang tie ( S chool of astronau t ics , B eijing U n iv . of A eron aut ics and A stronau tics , B eijing 100083 , Ch ina Abstract : T he hybrid m

9、ultilayer com posite structures consist o f la yers w ith different ther m a l conductiv ity and con st itutive constants . T o ana ly ze the in ternal heat transferm echan ism and the therm o -e lastic characterist ics o f the hy brid structure , three -di m ensional m odels are required to get the

10、 m ore accurate resu lts . U tilized the equ iv a lent e le m ent based on th ree -d i m ensional heat transfer th eory and Ga lik in f in ite e lem en t m eth ods fo r heat conduction , the resu lts w ith higher accuracy and less com putat io n are ach ie ved . T he d ifficulty due to th in er sing le layer is so lv ed by in troduc ing the concept of equ iv alen t elem en t possib ly in clud ing one or few layers , th us the su ff icient topo lo gy infor m at io n can be used to ana