International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 06 Issue: 07 | July 2019 p-ISSN: 2395-0072 www.irjet.net NON-DESTRUCTIVEsDETECTIONs&sCHARACTERIZATIONs OFs DAMAGESsINsHONEYCOMBsCOMPOSITEsSTRUCTURES Sangita Kumari1, Er. Rahul Malik2, 1M.tech Student, P.M. Group of Institutions, DCRUST Murthal, Sonipat, Haryana of Department, Mechanical Engineering, P.M. Group of Institutions, DCRUST Murthal, Sonipat, Haryana ---------------------------------------------------------------------***---------------------------------------------------------------------developed throughout the course of this research. Various Abstract –This thesis discusses many existing methods of 2Head different detection techniques have been addressed, ranging from the tap test to air coupled ultrasonic. non-destructive evaluation used on honeycomb structures ranging from ultrasonic transduction to various lows frequency techniques. The focus, however, is given to newly developed technique based on hysteresis effects in forcedisplacement curves. The area enclosed by the hysteresis loop represents the amount of energy absorbed by the samples during the loading and unloading phases. The great advantage of this method is that it only requires access to one surface of the structure to generate a force displacements curve. A mechanical testing machine could take up to 15 minutes to produce a single force-displacement curve, this method will produce the same curve in seconds. Much of this research was devoted to the testing and development of the techniques used to deduce a force-displacement curve from an accelerometer tap. Keywords- Delamination, Micro cracking, Thermography, Shearography, Computer Aided Tap Test 1. INTRODUCTION A honeycomb composite differs from a solid laminates in its structure. The honeycomb composite makes use of a light weight material fashioned into a honeycombs structure with a high load bearing ability in relations to its weight. The honeycomb is then sandwiched between two face sheets which are solid laminates. Composites, unlike aluminum, can have defects embedded within the material, ranging from delamination between plies to micro cracks and porosity in the matrix. Most cracks ins aluminums propagates to the surface because they do not have to cross materials interfaces, making them easily detectable. Cracks in composites however are stopped by each ply interface, making them much more difficult to detect. As a result, structural uncertainties requires airplanes manufactures to over design composites aircraft, taking away much of the light weight advantages of the composite material. Non destructive evaluation gives manufacturers the ability to reducesor eliminates the over design of composite materials, allowing them to make full use of their lightweight advantage. For this reason the development of non 1.1 COMPOSITEs DEFECTS 1.1 Defects In The Laminate-In a composite structure, the laminate constitutes a composition of materials made up of fibers and resin matrix. Several plies are built up to form the face sheets or laminate. The face sheet tends to be more resilient to damages than the core, though damages cans stills occur. Many times the damages cans occurs before the structures has ever entered service. Poor layups conditions ors flawed fabrications cans causes various types of defects in the faces sheet. The majority of in-services damages ins faces sheets comes from impacts damages, which cans causes various defects within the layup, some of which remains hidden to the naked eye. 1.2s Delamination-As delamination occurs when as gaps forms betweens twos plies of deferent fiber orientation. Dues to the facts that theses composites are usually assembled ply bys ply, poor layups conditions cans be as causes of delamination. Ifs manufacturing conditions are not clean, unwanted particles, such as dust, cans be introduced into the interfaces between the plies. Faulty bonding conditions will result, which leads to as delamination. There exist as resins rich areas which wills be lacking in fibers. This sections is the weakest points of the twos ply regions and ass as results becomes as failures points when the structure is puts under as load. 1.3s Micro cracking-Ins additions to delamination, matrix micro cracking also presents itself ass as commons defects ins solids laminates. It is ones of the many types of defects associated with impacts damages, yet the damages cans be caused by thermals cycling as well. This structures was thermally cycled from rooms temperatures to cryogenics temperatures several times to induces severe matrix micro cracking. destructive techniques is essential to the use of composites within any structure. A focus on honeycomb composites and their associated damages must be outlined in ordered to evaluate the new detection techniques © 2019, IRJET | Impact Factor value: 7.211 | ISO 9001:2008 Certified Journal | Page 2111 International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 06 Issue: 07 | July 2019 p-ISSN: 2395-0072 www.irjet.net types of methods involving infrareds thermograph which are actively beings used ass nondestructive techniques; they include: Traditional Thermograph, Flash Thermograph ors Thermal-Waves Imaging, ands Vibro Thermography. 2.3s Shearography-Another popular optical, non-contacts 1.4s Cracking Ors Buckling-Cracking ors buckling takes places when as sandwiched composites is puts under an excessive compressive load. When the loads exceeds the limits of the structure, the cores buckles ands leaves as fractures lines ins the cores which often takes the shapes of as “smile” centered below the impacts site. methods is shearograpy; digitals speckles shearography is starting to make its way into non destructive evaluation. It is an inter Ferro metric method which uses images obtained from as structures whiles at rests and whiles loaded. When the surfaces of the structures is illuminated by the laser, the cameras produces twos sheared images which interferes with each other producing as speckles pattern. These images are obtained while the structure is at rest and loaded using the same highs resolutions film, where the speckles patterns wills changes whiles the structures is loaded. The twos speckles patterns interferes with each other, revealing as macroscopic fringes patterns which correlates to the stiffness of the material. 2.4s Developments of Taps Test Method-Aside from visual inspection, manual, hearing-based, tap test is arguably the most practiced inspection technique on composites, especially on bonded sandwich structures. s Because of its wide use, as reals improvements of the taps tests methods wills haves as significant impacts on the NDI(Non Destructive Inspection)s of composites. 2.5s Computers Aided Taps Test-The Computers Aided Taps Test (CATT)s is as methods which makes uses of an accelerometers and electrics circuits to captures the impacts duration, τ, of the tap. The CATTs systems is able to stores theses τ values and plots very informative contours maps over the surfaces of the structure. Figs shows alls components of the CATTs systems ass wells ass an examples of as CATTs images produced on the computers screen. The photos also shows as magnetic carts in the foreground, which provides as quick, semi-automatic method of obtaining alls the τs values over the surfaces of the structure. 2. EXISTINGs INSPECTIONs METHODS 2.1s Ultrasonic Transduction Ultrasonic transduction is as very popular techniques used to inspects composites structures. It is able to detect delamination, micros cracking, porosity, skin-to-cores disbands, and as hosts of others defects commons among composites materials. As selected frequency is dependents upon the mediums used and the thickness of the material, where lowers frequencies are able to penetrate further into the material. Ultrasonic transductions is also hampered bys very expensive ands complex scanning systems needed to collects the data ands generates an image. 2.2s Thermography Whiles ultrasonic makes uses of sounds waves propagating though a material thermography makes uses of thermals waves propagating from the surfaces into the material. Theses waves are outsides the visible spectrums of light, having longer wavelengths than those contained within the visible spectrums of light. This sections wills outlines three © 2019, IRJET | Impact Factor value: 7.211 | s Figs 1.s As stiffness images of as Boeings 747s outboards spoilers generated by taps test ISO 9001:2008 Certified Journal | Page 2112 International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 06 Issue: 07 | July 2019 p-ISSN: 2395-0072 www.irjet.net REFERENCES Cores Splice Actuators fitting Plys Drop-offs Leadings Edge Cores Splice Figs 2.s B747s outboards spoiler (left)s and its resulting taps tests image(right). 2.6s Image-Based NDIs for Composite Inspection Ultrasonic inspection, when implemented with mechanized automated scanners generates scans images and is widely used in the laboratories and for the inspections of manufactured composites products. When used in the fields ors ins as maintenances hangar, ultrasonic inspections is typically carried outs with as flaws detector. Lows frequency bonds testing and taps tests are not imaged-based techniques. Ins the inspections of composites structures the advantages of an image-based techniques cannot be over emphasized Bys having the inspections results presented ins an images forms as completes coverage of the inspected areas is ensured. As recently developed approach for makings manual, imagebased “C-scans” using ultrasound, eddy current, ands lows frequency bonds testing (mechanicals impedances analysis)s exploits the existences of off-the-shelf, lows cost, commercials products with positions encodings capability. The NDI output, such as the amplitude or time-of-flight of an ultrasonic signal, is combined with the position information by software in the generation of the scan image. 3. CONCLUSIONS As the use of composite increases, especially in the next generation of airplanes, there will be a greater need for nondestructive inspections procedures for quality’s assurances by the manufacturers. The challenges wills includes efficient inspections of thick primary structures’ Specifics fields inspections needs of the news generations of composite-intensives airplanes may not arises until they are ins services for as numbers of years. Mores bonded structures are now classifieds ass primary structures and wills receives more inspections attention. The uses of foamcored sandwiches are also on the rise, with the accompanying NDIs needs. Theses twos techniques were discussed ins detail, although no real developments were made to theses techniques during the courses of the research; they were simply used ass as reference. © 2019, IRJET | Impact Factor value: 7.211 | [1]s Baker, A.s Dutton, S.s Kelly, D.s (2004).s Composites Materials for Aircrafts Structures. Americans Institutes of Aeronautics and Astronautics, Inc. [2]s Shull, B.E.s grey, J.N.s (1989).s X-Rays Measurements and Porosity Ins Graphite/Polyimides Composites. Reviews of Progress Ins QUANTATATIVEs NONDESTRUCTIVEs EVALUATIONs Vol. 8B,s pg. 1589 [3]sHsu,sD. (2006).Non destructive Evaluation of Damage in Composite Structures. Americans Society for Composites Meeting [4]sKommareddy, V.s (2003).s Air-coupled ultrasonic measurements ins composites. Iowar States University. [5]sNationals Instruments (2008).s Fundamentals of Ultrasonic Imaging and Flaws Detection. http://zone.ni.com/devzone/cda/tut/p/id/3368s Dates Referenced: 3/10/08 [6]s Kang, K.s Choi, M.s Kim, K.s Cha, Y.s Kang, Y.s Hong, D.s Yang, S.s (2006).s Inspections of Impacts Damages ins Honeycombs Composites Plates Bys ESPI,s Ultrasonic Testing, ands Thermography. Asia-Pacific Conferences on NDT,s 5ths -s 10ths Nov. 2006 [7]sShepard, S.M.s Ahmed, T.s Lhota, J.R.s (2004).s Experimental Considerations ins Vibro thermography. SPIEs Thermosense, Aprils 12-16,s 2004 [8]sRosencwaig, A.s Opsal, J.s (1986).s Thermals Waves Imaging and Thermos acoustics Detection. IEEEs Transactions on Ultrasonics, Ferroelectrics, ands frequency control, Vol. UFFC33,s No.5 [9]sKalms, M.s (2005).s Mobiles Shearography The Internationals Society of Optical Engineers April, 2005,s Vol. 10,s No. 4 [10]sHsu, D.s Barnard, D.s Peters, J.s Dayal, V.s (2000).s Physicals Basis of Taps Tests ass as Quantitative Imaging Tools for Composites Structures on Aircraft. Reviews of Progress ins Quantitative Nondestructive Evaluation. [11]sZukas, J.A.s Nicholas, T.s Swift, H.F.s Greszczuk, L.B.s Curran, D.R.s (1982).s Damages ins Composites Materials dues to Lows Velocity Impact. ImpactsDynamics. Johns Wiley and Sons, Inc. pp. 55-94 [12]s Cawley, P.s (1990).s Lows Frequency NDTs Techniques for the Detections of Disbands and Delaminations. British Institutes of Non-Destructives Testing, Vol.32,s No.9,s Septembers 1999 ISO 9001:2008 Certified Journal | Page 2113 International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 06 Issue: 07 | July 2019 p-ISSN: 2395-0072 www.irjet.net AUTHORS PROFILE Sangita Kumari, M.tech Student at PM College of Engineering, Sonipat , Haryana. Er. Rahul Malik, completed B.Tech (Mechanical Engineering) from Maharshi Dayanand University, Rohtak in 2008 and M.Tech. (Specialization: Design) from Deenbandhu Chotu Ram University of Science and Technology, Murthal Sonipat in 2011. Currently working as an Head of Department (Mechanical Engineering) with PM College of Engineering, Sonipat, Haryana, India. © 2019, IRJET | Impact Factor value: 7.211 | ISO 9001:2008 Certified Journal | Page 2114