Center for Composite Materials and Structures, Harbin Institute of Technology, Harbin , P.R. China

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1 21 st Internatonal Conference on Composte Materals X an, th August 2017 CYLINDER TYPE PYRAMID LATTICE SANDWICH COMPOSITE STRUCTURE ANALYSIS OF THE AXIAL COMPRESSION PERFORMANCE Zhang Hanq 1, Wang Bng 1, Wang Shxun 2, Wu Lnzh 1 1 Center for Composte Materals and Structures, Harbn Insttute of Technology, Harbn , P.R. Chna 2 Bejng Insttute of Astronautcal Systems Engneerng, Bejng , PR Chna Keywords: Composte, Pyramd lattce, Cylndrcal shell, Axal compressve performance ABSTRACT The present work provded the access to study the unaxal compresson behavour of cylnder type pyramd lattce sandwch composte materal structure. In the unaxal compresson tests, the man falure modes are the falure of Euler bucklng of cylndrcal shells, overall bucklng, local bucklng between corrugated panel and shell wall collapsng. In addton to expermental testng, fnte element models for compresson smulatons have been developed usng ABAQUS software. It must be ponted out that, n the course of the experment, the greater the thckness of the specmen, the shorter the course of ts local bucklng, the more obvous the collapse of the panel. As a result, the pyramd lattce cylndrcal shell panel s the man load bearng component, and the thckness of the panel s the man factor of carryng capacty. Therefore, the load bearng capacty mprovement of lattce cylndrcal shell can be realzed by changng the thckness of the panel and the core desgn should proceed wth the advancement of producton process. 1 INTRODUCTION In the aerospace feld, a mult-functonal, hgh loadng effcency, hgh relablty and low cost structure has always been researched by desgners. Sandwch structure s generally determned by the strength and stffness of large thn panel and mddle thck but lght core composton [1-5]. Accordng to the dfferent types of materals, usng dfferent means to make the connecton as a whole, so as to realze the load transfer between the panel and core [6]. The exploraton of lghtweght sandwch structure can be traced back to the earlest wood as materal desgn of the wng [7]. After the concept of the sandwch structure s put forward, scholars have developed varous sandwch structure, early for entty foam sandwch structure, n order to enhance the bearng capacty of the structure, after the Z- pn enhance foam sandwch structure. The research and development of the sandwch structure to a new chapter wth the emergence of lattce sandwch structure. Sandwch cylndrcal shell structure manly has three confguratons: nner and outer panel and core, outsde board and core, and only core wth no panel [8-10]. Carbon fber composte cylnder s manly used as rocket farngs, the servce condton s very complex [11,12]. In the process of rocket launch, on account of the nstablty of the arflow s apt to cause the vbraton of the key body, so t s necessary to have the ablty to resst the strong vbraton. At the same tme, n the launch process, the structure s manly subjected to axal compressve load, so the structure must have a strong axal energy absorpton capacty, n order to meet the requrements of the servce. Havng the characterstcs of perodc arrangement of carbon fber renforced resn matrx composte lattce sandwch structure materal s becomng the object of our study because of ts low densty, excellent mechancal propertes and heat conducton reserve space. To date, a great deal of research work has been proved that lattce sandwch structure has good energy absorpton functon [13-17]. However, prevous studes on the preparaton technology has Correspondng author, Tel.: E-mal address:zhq951159@163.coom (Hanq Zhang).

2 Zhang Hanq 1, Wang Bng 1, Wang Shxun 2, Wu Lnzh 1 always been more complex, and that less research n sandwch shell wth the shell structure s commonly used n engneerng practce [18,19]. Therefore, ths paper adopts ntegratve moldng process for the preparaton of lattce core, the specmen of cylnder lattce sandwch structure s prepared for the axal compresson test and mechancal performance smulaton to analyss the axal compresson performance and falure mechansm. 2 EXPERIMENTS 2.1 MATERIALS Pyramd lattce sandwch cylndrcal related parameters:in ths paper, the research of carbon fber composte materals pyramd lattce sandwch cylndrcal, raw materal s carbon fber (T300-3 k) renforced resn matrx compostes n plan weave cloth materal. Preparaton of hot pressng de mold s desgned ndependently by our laboratory, s shown n Fg.1. The core and the nsde and outsde board are plan weave cloth, hot pressng lamnated plates after sngle layer thckness of 0.2 mm, specmen dameter s 140 mm, nner dameter s 115 mm, specmens of the total heght s 172 mm. Fg.1: Hot pressng mould Ⅰ-Core column, Ⅱ-The nner core, Ⅲ-The outer core, Ⅳ-The outsde clampng mold Preparaton process ncludes the followng four steps: (a) Pretreatment of the mold:usng acetone to the mold for cleanng. After watng for mold to dry, the nner core column splced together,and release agent on the surface mold. (b) Preparaton of cylnder core: Accordng to the sze of the cylndrcal specmen, presoak materal cuttng nto the requred sze. Then, cuttng out the requred number of trapezodal hole on prepared presoak materal, and wrapped t n the column on the nner core. After clampng fxed, pressurzed heatng and coolng of cylnder core demoldng. The preparaton process s shown n Fg.2. Fg.2: The preparaton process

3 21 st Internatonal Conference on Composte Materals X an, th August 2017 (c) Preparaton of panel:the general process s smlar to the preparaton of the core wth panel mold. (d) Assembly and processng: The flm s used to cement core and panel. In addton, the jont between the panels should be enhanced. The preparaton of the panel and core s shown n Fg.3. (a (b (c (d. (e Fg.3: The preparaton of the panel and core. (a) Panel front vew; (b) Panel profle; (c) The nner and outer panel; (d) Core front vew; (e) Core vertcal vew 2.2 AXIAL COMPRESSION TESTS The maxmum compresson load of 100 tonnage WAW-1000 unversal testng machne s used for the axal compresson test. Wth the method of dsplacement control s to load, loadng speed s 0.5 mm/mn. The stanless steel plate fxture to fxed at both ends up and down of the specmens, so as to guarantee the unversal testng machne n the process of loadng, the specmen of strength was conducted along the axal drecton. In order to better understand the deformaton of specmens under axal compresson loadng stuaton, take the way on the specmen stran gages to observe the change of specmen n the process of expermental stran. Accordng to a report n the lterature, the specmen area s manly damage panel part. Therefore, outer panel decorate seven stran gauge whch are basc covers the man deformaton area, and decorate a stran gauge on nner panel mddle poston, to determne the deformaton of the panel under the axal compresson load. Stran gauge poston as shown n Fg.4. Experment was carred out on three groups of dfferent thckness of the specmen axal compresson experment, the thckness s 0.4 mm, 0.6 mm and 0.6 mm respectvely.

4 Zhang Hanq 1, Wang Bng 1, Wang Shxun 2, Wu Lnzh 1 Fg.4: Sketch map stran gauge Each type of specmen we made three experments, the data wll be averaged to get table1. thckness (mm) weght(g) theoretcal value smulaton value (KN) (KN) expermental value (KN) Table1:Axal compresson bearng capacty of the theoretcal value, the smulaton value compared wth the expermental value In the process of the axal compresson test, observaton found that the greater the thckness of the specmen the local bucklng of the shorter the journey, panel crushng, the man falure mode to the man panel crushng, the more obvous. Thckness of 0.4 mm, 0.6 mm and 0.8 mm specmen lmt load can reach 38.3 KN, KN and KN respectvely. Accordng to the expermental results and theory and the comparson of smulaton results, found that for the thcker the panel of the specmen, due to t s n the axal bearng capacty of strong, not easy to occur bg deformaton, so the lnear local bucklng s not obvous, the expermental results on the low sde. Theory and smulaton of expermental results s slghtly lower than the reason manly has two ponts: the frst s the performance of the barrel s lower than the performance of the lamnated plates, so wth the basc mechancal parameters of the plate wth the theory and smulaton value slghtly hgher; The second reason s that n the process of preparaton has many damage and defects whch make the expermental value low. Progressve falure mode s shown n Fg.5.

5 21 st Internatonal Conference on Composte Materals X an, th August 2017 Fg.5.The outer wall gradual falure mode. (a) 0.4mm, (b) 0.6mm, (c) 0.8mm 3 SIMULATION Frst use of drawng software SOILDWORKS to map the dfferent thckness of the core and the panel, then the geometry mported nto the ABAQUS software. Consderng the model s to establsh the rules of the cylndrcal shell, so that RTZ has been choose n modelng cylndrcal coordnate system. The bottom of the crcular arc n the model bult n the plane R-T and Z drecton corresponds to s the heght of the drecton of specmen. Besdes, for the real envronment of the smulaton test, the pressure plate s ntroduced nto the model. Accordng to the already lsted structure sze, the thckness of the specmen sze s far less than the overall structure, and can be gnored thckness drecton stress, thus selected unt types to S4R. In the grd, n order to ensure the accuracy of classfcaton grd number can be estmated at the same tme, the partton mode selecton and slghtly, meshng the result s shown n Fg.6. Fg.6. Specmen meshng Due to the cylnder n servce wll be along the axal load, so at the specmen durng the smulaton and the bottom of the pressure plate clamped constrants, and exerted load drecton do not restran the Z drecton. In the center of the pressure plate, defne a reference pont, wll be the reference pont and

6 Zhang Hanq 1, Wang Bng 1, Wang Shxun 2, Wu Lnzh 1 the pressure plate surface coupled together, and then from the reference pont dsplacement load of 0.5 mm/mn. Ths paper adopted by the smulaton analyss for the bucklng egenvalue bucklng analyss, and s often used to estmate the rgd structure of bfurcate load. Egenvalue bucklng analyss s also known as lnear bucklng for lnear perturbaton process, wth small dsplacement and stran based on lnear elastc theory. At every stage of the external forces appled, s based on the structure of the ntal confguraton balance equaton. When the load reaches the crtcal value, the structure of the confguraton wll suddenly transformed nto another state of equlbrum, ths process s called bucklng. In general, the egenvalue bucklng was used to analyss the rgd structure of bfurcate load. Rgd structure s manly desgned to wthstand the axal load, rather than bendng behavor, ts before bucklng deformaton usually s very small. Before dd not meet bfurcate load reflects s very hard, after reachng bfurcate load, specmen showed a very low stffness characterstcs. Specfc analyss process s as follows: In problem of egenvalue bucklng load made the model of stffness matrx sngularty, therefore has a nontrval soluton of the followng equaton: K S X F ( ) (1) If the analyss s lnear, can be multpled by a constant load and stress state, at ths tme: K S X F ( ) (2) In a bucklng model, dsplacement may be greater than the load does not ncrease, so the type s correct. K S X F ( ) (3) By solvng the type on, get t: K S 0 ( ) (4) For solvng the equaton of egenvalue bucklng. Here [K] and [S] as the constant value, therefore the general drectly places value on the structure of 1N of the load, the output of ABAQUS egenvalue bucklng load values for the structure. The smulaton process need convergence analyss was carred out on the grd, results tend to be stable when the grd sze s 2.3.After the bucklng stress nephogram of as shown n Fg.7. Fg.7. Specmen stress nephogram 4 CONCLUSIONS In ths paper, based on the core of cylnder pyramd lattce structure axal compresson performance tests on composte materal, won the ultmate load and falure mode of composte materals. Regardless of the thckness of the panel after the local bucklng falure modes are frst crushng process. And the thnner the specmens, the local bucklng, the longer, the more obvous bucklng process. Thckness of 0.4 mm, 0.6 mm, 0.8 mm specmen lmt load can reach 38.3kN, 79.08kN and kN respectvely, and forecast the correspondng theory s better, more accurate for the

7 21 st Internatonal Conference on Composte Materals X an, th August 2017 predcton of specmen. Insde and outsde of the plate s thck, t can wthstand the lmt load of value wll be greater. But nsde and outsde board usng splt preparaton wth enhancement of renforcement ways can not show the full carryng capacty of the structure. Enhanced after falure the obvous stress concentraton n splt place. If consderng the panel s nterrupted preparaton, combned wth a wndng way also can further enhance the lmt load, gve full play to the potental of bearng structure. ACKNOWLEDGEMENTS The present work s supported by Natonal Natural Scence Foundaton of Chna under grant Nos and Nos

8 Zhang Hanq 1, Wang Bng 1, Wang Shxun 2, Wu Lnzh 1 REFERENCES [1] Evans A G. Lghtweght materals and structures[j]. MRS bulletn, 2001, 26(10): [2] Allen H G. Analyss and desgn of structural sandwch panels [M].Oxford: Pergamon Press, [3] Pandt M K, Shekh A H, Sngh B N. An mproved hgher order zgzag theory for the statc analyss of lamnated sandwch plate wth soft core [J]. Fnte Elements n Analyss & Desgn, 2008, 44(9-10): [4] Van Straalen I J. Comprehensve overvew of theores for sandwch panels[j]. Modellng of Sandwch Structures and Adhesve Bonded Jonts, [5] Bunyawanchakul, P, Castané, et al. Non-lnear fnte element analyss of nserts n composte sandwch structures[j]. Compostes Part B Engneerng, 2008, 39(7-8): [6] Zenkert D. The Handbook of Sandwch Constructon[M]. London, UK: Chameleon Press Ltd.,1997. [7] Evans A G, Hutchnson J W, Fleck N A, et al. The topologcal desgn of multfunctonal cellular metals[j]. Progress n Materals Scence, 2001, 46(3): [8] Fan H, Fang D, Chen L, et al. Manufacturng and testng of a CFRC sandwch cylnder wth Kagome cores[j]. Compostes Scence and Technology, 2009, 69(15): [9] He J, Ren M, Sun S, et al. Falure predcton on advanced grd stffened composte cylnder under axal compresson[j]. Composte Structures, 2011, 93(7): [10] Vaslev V V, Razn A F. Ansogrd composte lattce structures for spacecraft and arcraft applcatons[j]. Composte structures, 2006, 76(1): [11] Shuart M J. Advanced composte structures and materals technologes for launch vehcles[j]. Internatonal emnent speaker seres (Australan dvson), [12] Applcaton of advanced grd-stffened structures technology to the Mnotaur payload farng[m]. Defense Techncal Informaton Center, [13] Lane S A, Hggns J, Bskner A, et al. Out-of-Autoclave Composte Farng Desgn, Fabrcaton, and Test[J]. Journal of Manufacturng Scence and Engneerng, 2011, 133(3): [14] Krvanek T M, Yount B C. Composte payload farng structural archtecture assessment and selecton[j] [15] Km T D. Fabrcaton and testng of composte sogrd stffened cylnder[j]. Composte structures, 1999, 45(1): 1-6. [16] Weaver T J, Jensen D W. Mechancal characterzaton of a graphte/epoxy sotruss[j]. Journal of Aerospace Engneerng, 2000, 13(1): [17] Weaver T J. Mechancal Characterzaton of a Graphte/epoxy Isotruss Subject to Smple and Baxal Loads[M] [18] Huybrechts S M, Menk T E, Wegner P M, et al. Manufacturng theory for advanced grd stffened structures[j]. Compostes Part A: Appled Scence and Manufacturng, 2002, 33(2): [19] L W, Sun F, Wang P, et al. A novel carbon fber renforced lattce truss sandwch cylnder: Fabrcaton and experments[j]. Compostes Part A: Appled Scence and Manufacturng, 2016, 81: