复合板中爆炸力对复合板造成的变形检测方案(其它无损检测仪器/设备)

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IN APPLICATION High Speed DIC applied to Blast Testing ofSandwich Composite Materials Introduction Recent advances in composite manufacturing have occurredpredominantly in the aerospace， marine， automotive and relatedindustries. Whilst， formerly， naval vessels were constructed fromsteel， composites provide a significant weight reduction andincrease in stealth properties whilst maintaining high strengthproperties. However composite sandwich materials have yet to bewidely adopted in the construction of naval vessels despite theirexcellent strength to weight ratio and low radar return. One barrierto their wider use is our limited understanding of their performancewhen subject to air blast. Experimental Setup Carbon fibre reinforced polymer (CFRP) and Glass fibre reinforcedpolymer (GFRP) were blast tested in this research. Each panelwas constructed with a 25mm thick closed-cell M130 CorecellMstyrene acrylonitrile (SAN) foam core. The 1.6 m x 1.3 m sizedpanels were subject to 100 kg TNTequivalent at a stand-off distance of 14 m. This represents a surfaceblast threat， where the shock wave propagates in air towards thesubject. The experiments were carried out at RAF Spadeadam，Cumbria， UK. Figure 1： Schematic diagram of the experimental layout on thetest pad Principle High-speed 3D digital image correlation (DIC) was employed tocapture full-field displacement plots of the rear surface of the tar-gets. Pairs of high speed video cameras were positioned inside eachcubicle， whereby each cubicle supported both types of specimens(two pairs of specimens were tested) and a frame rate of 2000 fpswas used to image the blast event. Figure 2 shows images capturedby an external camera during the event. Figure 2： lmages taken at regular intervals with the shock waveimpinging on test samples GL1 and CA1 after 16.5 ms. LaVisionUK Ltd LaVision Inc. Downsview House/ Grove Technology ParkGrove/ Oxon/ 0X12 9FF， United KingdomE-Mail： sales@lavision.com/www.lavisionuk.com ( 2 11 W . M ichigan Ave. / Suite 100 ) ( Ypsilant i ， MI 48197 / USA ) ( E - m a i l ： s a l es@lavisi o ni n c.com/www.lavis i oninc .c om ) High Speed DIC applied to Blast Testing ofSandwich Composite Materials Department of Mechanical Engineering， Imperial College London， UK Results 22.5 ms 24.0 ms Figure 3： DIC analysis of blast on GL1 featuring contour plots ofout-of-plane displacement Clear indications of damage induced are shown in the DIC resultsshowing the maximum principle strains. There is a region ofmaterial in compression of around -1%when GL1 is at its peakrebound displacement (out towards the origin of the charge). Thisregion builds in strain due to the lack of support provided by thecore. A core shear failure propagated through the panel resultingin a front-skin failure as well which can be seen in the image takenby the external camera. GL1 at 31.5 ms after detonation GL1 Figures 4a&b：DIC analysis of GL1 showing the maximum principalstrain (a) and the mirrored images of the damaged front faces ofthe panel (b) LaVisionUK Ltd Subsequent to the blast tests the panels were recovered and sub-jected to controlled static loading in compression to assess theability of the panels to support applied load after blast damage hasalready occurred. It could be seen in this data that it is possible toanticipate where failure will occur based on the strain field evolutionat lower loads. Conclusion The tests showed that the CFRP-skinned sandwich panels provideda greater resistance to the blast wave impact， deflecting a smalleramount compared to the GFRP-skinned panels. The post-blastdamage inspection showed that， unlike the GFRP panels whichexperienced visible skin cracking， the CFRP panels suffered minimalto no visible skin damage but comparable severity of core damageto the GFRP panels. The trends observed here indicate that， ifif residual strength is a keydesign factor after severe blast， then a drop of two-thirds of theresidual compressive strength in CFRP and half in GFRP needs tobe taken into account in the design process. For further details please refer to Arora， H.， Kelly， M.， A. Worley， A.， Del Linz， P.， Fergusson， A.， Hooper， P.A. and Dear， J.P.“Compressive strength after blast of sandwich composite materials"Proceedings of the Philosophical Transactions of Royal Society，DOI： 10.1098/rsta.2013.0212 ( LaVision Inc. ) ( 2 11 W . M ichigan Ave. / Suite 100 ) ( Ypsilant i ， MI 48197 / USA ) LaVision GmbHAnna-Vandenhoeck-Ring -Goettingen / GermanyE-Mail： info@lavision.com/www.lavision.comPhone： ( / Fax： ( hone： +()- Fax： +()-el.+()Fax +() Downsview House/ Grove Technology ParkGrove/ Oxon/ OXF， United KingdomE-Mail： sales@lavision.com/www.lavisionuk.comLaVision GmbHAnna-Vandenhoeck-Ring -Goettingen / GermanyE-Mail： info@lavision.com/www.lavision.comE-mail： sales@lavisioninc.com/www.lavisioninc.comTel.+()Fax +()hone： ( Fax： ( hone： +()-Fax： +()-