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Thursday, December 3, 2020 | History

3 edition of Surface crack analysis applied to impact damage in a thick graphite/epoxy composite found in the catalog.

Surface crack analysis applied to impact damage in a thick graphite/epoxy composite

Surface crack analysis applied to impact damage in a thick graphite/epoxy composite

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Published by National Aeronautics and Space Administration, Langley Research Center, For sale by the National Technical Information Service in Hampton, Va, [Springfield, Va .
Written in English

    Subjects:
  • Graphite.,
  • Composite materials.

  • Edition Notes

    StatementC.C. Poe, Jr., C.E. Harris, and D.H. Morris.
    SeriesNASA technical memorandum -- 100600.
    ContributionsHarris, C. E., Morris, D. H., Langley Research Center.
    The Physical Object
    FormatMicroform
    Pagination1 v.
    ID Numbers
    Open LibraryOL15279901M

    Figure 1 for bbron-epoxy, graphite-epoxy, and glass-epoxy laminates. Thus, an example exists in which the damage inflicted by a local hard par-ticle impact can be equated, in terms of residual strength, to damage inflicted by an artificially implanted stress concentration. @article{osti_, title = {Development and validation of bonded composite doubler repairs for commercial aircraft.}, author = {Roach, Dennis Patrick and Rackow, Kirk A}, abstractNote = {A typical aircraft can experience over 2, fatigue cycles (cabin pressurizations) and even greater flight hours in a single year. An unavoidable by-product of aircraft use is that crack, impact, and.


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Surface crack analysis applied to impact damage in a thick graphite/epoxy composite Download PDF EPUB FB2

The residual tensile strength of a thick graphite/epoxy composite with impact damage was predicted using surface crack analysis. The damage was localized to a region directly beneath the impact site and extended only part way through the laminate.

The damaged region contained broken fibers, and the locus of breaks in each layer resembled a Cited by: 6. Get this from a library.

Surface crack analysis applied to impact damage in a thick graphite/epoxy composite. [C C Poe; C E Harris; D H Morris; Langley Research Center.]. nasa technical memorandum surface crack analysis applied to impact damage in a thick g raphite/epoxy composite (#asa-th) surface crack analysis n 8 8- 50 applied to ihpact damage in a thick graphite-epoxy coflposite (nasa) 33 p cscl 11d unclas g3/24 c.

poe, jr., c. harris, and d. morris. Impact damage is highly dependent upon the nature of the threat and conditions associated with the impact event.

This chapter will provide an overview of impact damage threats that are common to composite aircraft structures and describe the relationship of these threat sources to the damage that is by: 6. Fractography of the destruction of epoxy composite samples without TEG, Fig.

7a, is characterized by a rather smooth fracture surface, which indicates a low ability to crack by: 3. On the prediction of tensile strength after impact of composite laminates. Prediction of the residual tensile strengths of carbon-fiber/epoxy laminates with and without interleaves after solid particle erosion.

Surface crack analysis applied to impact damage in a thick graphite/epoxy composite. Uniform shell designs. Epoxy-based composite materials are widely used in load-bearing applications, e.g., automotive, aerospace, construction, oil and gas, and marine industries, because of their low cost, good mechanical properties, high specific strength, super adhesiveness as well as good heat and solvent resistance.

For this reason, there is a growing need to. The residual tensile strength of a thick graphite/epoxy composite with impact damage was predicted using surface crack analysis. The damage was localized to a region directly beneath the impact. Poe's 6 research works with citations and reads, including: Role of Mechanics of Textile Preform Composites in the NASA Advanced Composites Technology Program.

Home Browse by Title Reports Damage-Tolerance Characteristics of Composite Fuselage Sandwich Structures With Thick Facesheets. Damage-Tolerance Characteristics of Composite Fuselage Sandwich Structures With Thick Facesheets February.

A composite cylinder has an inside diameter of 6 in. and an outside diameter of 12 in., the common surface between the two parts being of 9 in. diameter. Calculate the diametral interference between the parts if an interface pressure of lb/in.

2 is required (E = 30×10 6 lb/in. 2).Also find the hoop stress at the bore when an internal pressure of 50, lb/in. 2 is applied, and verify. This paper is a review of low-velocity impact analysis of composite structure.

Low impact velocity and damage mode due to impact load and failure criteria’s are explained. Impact of thick CFRP laminates: the effect of impact velocity. Breen, C, Guild, “ A model for predicting damage in graphite/epoxy laminated composites resulting.

This method is used to calculate the guided wave field produced in a thin unidirectional graphite/epoxy composite laminate by a dynamic surface point load. The results are compared with those obtained from a finite element analysis, showing excellent agreement.

Ko¨nig M, Kru¨ger, R, Kussmaul, K, v. Alberti, M, and Ga¨dke, M (), Characterizing static and fatigue interlaminar fracture behavior of a first generation graphite/epoxy composite, Composite Materials: Testing and Design, 13th Volume, ASTM STPSJ Hooper (ed), Am Soc for Testing and Materials, Philadelphia, PA, 60–   Keywords – graphite fillers, damage tolerance, compression-after-impact, laminates, mechanical testing I.

INTRODUCTION In terms of structure, materials can be divided into four basic categories: metals, polymers, ceramics and composites. A composite structure is a material composed of two or more phases combined in a macroscopic scale. The dispersity of graphene (GE) in the matrix has an important influence on the thermal, mechanical, and electrical properties of its derived composites.

In this paper, surface modification with a silane coupling agent and a double injection method were used to improve the dispersity of GE in epoxy resin (EP). The thermal, mechanical, and electrical properties of modified graphene/epoxy resin. The damage to all of the hybrid panels was quite significant, however, Hybrid-(GCGFGCG) suffers from the least damage, 10 and 20%, and the lowest projectile penetration, 9 and 15 mm under impact at 75 and 90 m s −1 respectively.

The damage caused by the impacting projectiles for the Hybrid-(GCFGC) and Hybrid-(GCFCG) panels was very similar. Impact tests are carried out on a cross ply graphite epoxy plate using an instrumented impact testing system. The contact force and the surface motion caused by the impact load are recorded at several points on the plate surface away from the impact location and are analyzed based on theoretical simulations.

Interlaminar fracture behavior of a five-harness satin orthogonal woven fabric carbon/epoxy composite laminate loaded in Mode I, Mode II, and mixed mode has been investigated. Fracture testing employed the DCB, ENF, and MMB specimens.

Special emphasis was put on microscopic details of crack growth and their relation to fracture resistance. Fig. 5 is the matching surface containing polymer only. The width of the exposed glass surface is about two- thirds of the 1 mm diameter of the glass rod, because the incoming crack surface was slightly above the axis of the glass rod.

The crack passed upwards in Fig. 4 and downwards in Fig. As a graphite derivative, graphite fluoride (GrF) has a remarkable fracture toughness improvement effect on epoxy materials.

The fracture toughness variation of the epoxy could exert an influence on the low velocity impact resistance of the corresponding carbon fiber reinforced polymer (CFRP) composite. Therefore, the dependence of the low velocity impact resistance of the incorporated CFRP on.

3. Polymer/Metal Bonded Composite Structures. In addition to making high performance hybrid composite materials, bonding composites to metals is an effective method for repairing structural defects, maintaining the load carrying capability, and extending the service life of metallic structures [30–50].Adhesive bonding offers various advantages [43,46] and the repair of defective structures.

When the patch is applied to a part (either metal or composite) using hand pressure, the galleries are in intimate contact with the part surface. The galleries are maintained, alternately, at atmospheric pressure and at partial vacuum by a pneumatic system, and pressure transducers then detect crack formation or damage in aircraft structures.

composite patch were investigated through experimental and numerical study. Experiments involved fatigue tests of 2, 6, 10 mm thick specimens with edge crack repaired with unidirectional graphite/epoxy patch. Two types of patch configuration were used, i.e.

constant thickness patch and. Composites Part B: Engineering publishes impactful research of high quality on composite materials, supported by fundamental mechanics and materials science and engineering approaches. Targeted research may cover a range of length scales from nano, over micro and meso to full product/structure level, with a focus on Engineering embracing high performance applications spanning from low volume.

Gas permeability of various graphite/epoxy composite laminates for cryogenic storage systems Sukjoo Choi1, Bhavani V. Sankar* Department of Mechanical and Aerospace Engineering, P.O.

BoxUniversity of Florida Gainesville, FLUSA. "Strength of a Thick Graphite/Epoxy Rocket Motor Case after Impact by a Blunt Object," in Test Methods for Design Allowables for Fibrous Composites: 2nd Volume, ASTM STPC. Chamis, ed., Philadelphia: American Society for Testing and Materials, pp.

Google Scholar. keep the surface open and flat troweling to avoid enfolding air into the surface under the blade action. Insufficient vibration during compaction that does not ade-quately release entrapped air; or overuse of vibration that leaves the surface with excessive fines, inviting crusting and early finishing.

Finishing when the concrete is still. nasa technical memorandum simulated impact damage in a thick graphite/epoxy laminate using spherical indenters c. poe, jr. (basa-xb-loo) sibulated ileac3 g-aaage in n 3 a thick grapbi!ie/€eoxi laeillai€ usxbg siiieliical inden'iels (nasa) 55 f cscl ili) unclas.

Laminate theories are not adequate in describing the stresses due to indentation or for that matter 1 shows the load-deflection diagram of two dif- ferent 32 layer quasi-isotropic graphite/epoxy laminated plates indented by in- denters with diameters mm and these diagrams the nonlinear portion due to local indentation is not shown.

Failure analysis of a fibrous composite half-space subjected to uniform surface line load. ASME Journal of EngineeringMaterials Technology, Vol. No.2,pp (8 pages) [20] Y.S. Kwon and B.V. Sankar () "Indentation-Flexure and Low-Velocity Impact Damage in Graphite/Epoxy Laminates", ASTM Journal of Composites Technology and Research, 15(2) PDF ] [19] B.V.

Sankar and R.V. Marrey () "A Unit Cell Model of Textile Composite Beams for Predicting Stiffness Properties", Composites Science and. Epoxy Coatings for Graphite Yarn 5 Fatigue, and Ballistic Impact 5 Mechanical Properties o Graphite/Epoxy Composites 8 Fundamental Mechanical Analyses of Composite Data 18 Fabrication 19 Testing 20 III CONCLUSIONS 21 REFERENCES 22 I.

X.-F. Wu & Y. Dzenis, “Experimental study on dynamic delamination toughness of a graphite-fiber/epoxy composite with interfaces modified by nanofibers,” The 41 st Annual Technical Meeting of the Society of Engineering Science (SES), October, Lincoln, Nebraska.

Ramulu, “Propagation of a Small Surface Crack in Aluminum and Steel Alloys,” Optical Methods in Composites, SEM Fall Conference Proceedings on Surface Crack Research,pp. Ramulu and R. Taggart, “Subcritical Growth of Small Fatigue Cracks,” Fatigue Life: Analysis and Prediction, edited by V.S.

Goel, ASM publ. X-ray diffraction (XRD) and scanning electron microscopy (SEM) results showed that the graphite flakes were exfoliated from an original size ~ diameter and m 2 /g BET surface area to GNP sheets 14 nm thick, ~1–2 μm diameter and m 2 /g BET surface area after 20 hrs of milling. XRD also showed that the surface crystalline.

"Effect of Braiding Process on the Damage Tolerance of 3-D Braided Graphite/Epoxy Composites," presented at the 34th SAMPE Symposium and Exhibition, MayBook 2 of 2.

Google Scholar Li, W., T.J. Kang and A. El-Shiekh. delamination in graphite/epoxy laminates. The results showed that stitches effec-tively arrested the delamination. Dexter and Funk [3] investigated the impact re-sistance and interlaminar fracture toughness of quasi-isotropic graphite-epoxy laminates made of unidirectional Thornel K fibers/Hercules resin.

Surface Cracks A surface crack can be detected only if heat is applied on one side of the crack and allowed to conduct laterally in a direction orthogonal to the crack.

Figure 2 shows thermograms of two laminates containing surface cracks. Note the large increase in temperature which occurs   The thermal expansion behavior of unidirectional, balanced angle‐ply, and complex laminated graphite‐epoxy composites, is studied.

The expansion coefficient of the unidirectional composites is determined as a function of fiber orientation and is found to follow the simple equation. Figure 1.

Delta IV heavy. In addition, composite design could reduce fabrication cost. Delta II faring, Delta III faring, and interstage production data have shown that composite launch vehicle structures are less expensive than metal ones [].Graphite-epoxy composite cryogenic tank development began at Boeing (then McDonnell Douglas) in and continues today, primarily for .A transverse crack in 90° layers of CFRP laminate is mostly initial damage and is the origin of more serious damage of delamination and fiber breakage.

It is thus essential to evaluate quantitatively the fatigue life to transverse crack initiation of CFRP laminates for .Benjamin Hasseldine, Alan Zehnder, Bryan Keating, Abhendra Singh, and Barry Davidson. "Compressive strength of aluminum honeycomb core sandwich panels with thick carbon-epoxy facesheets subjected to barely visible indentation damage." Journal of Composite .