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Wednesday, July 29, 2020 | History

3 edition of A semi-micromechanic interlaminar strain analysis on curved-beam specimens found in the catalog.

A semi-micromechanic interlaminar strain analysis on curved-beam specimens

A semi-micromechanic interlaminar strain analysis on curved-beam specimens

final report, April-December 31 1990 under grant NCC 2-673

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  • 32 Currently reading

Published by National Aeronautics and Space Administration, National Technical Information Service, distributor in [Washington, DC, Springfield, Va .
Written in English

    Subjects:
  • Strains and stresses.,
  • Laminated materials.

  • Edition Notes

    StatementDuksung Joh.
    SeriesNASA contractor report -- NASA CR-189512.
    ContributionsUnited States. National Aeronautics and Space Administration.
    The Physical Object
    FormatMicroform
    Pagination1 v.
    ID Numbers
    Open LibraryOL18059293M

    For the DSBWC beam, unexpectedly, the strain on the outer surface (i.e., points-1) increased only modestly until the specimen began to yield, as shown in Figure 7c. This was indicative of the high stress concentration in this region. However, the compressive strain on the inner surface (i.e., points-3) behaved quite interestingly. The finite element analysis showed that the ILSS calculated from beam equation overestimates the strength by 5% for shear flexible composites. This reduction was found to be the same for both polymeric and carbon matrix composites. The test data confirmed the interlaminar shear failure and very low data scatter in measured strength.

    Full text of "Assembly induced delaminations in composite structures" See other formats N ASSEMBLY INDUCED DELAMINATIONS IN COMPOSITE STRUCTURES 1 o. J- 3 J. Goering, R. Bohlmann, and Dr. S. Wanthal McDonnell Aircraft Company McDonnell Douglas Corporation, St. Louis, MO E. Kautz Naval Air Development Center, Warminster, PA L. Neri . The straight and curved specimens were loaded in a three-point bending test, as seen in Figure 2. The straight beam was simply supported. The span between the supports was mm. The supports of the curved beam are pinned with a span of mm. An INSTRON H universal testing machine fitted with a load cell of 10 kN was used.

    O’Brien, T.: Mixed-mode strain energy-release rate effects on edge delamination of composites. In: AS (ed.) Effects of Defects in Composite Materials. American Society for Testing and Materials, pp. – () Google Scholar. Curved Beam Stress Deflection Design Spreadsheet Calculator. There are two approaches for the design of beams. The lower image shows the mesh, where the beam is subdivided into a number of beam elements represented by cylinders. Example: Create a curved beam between two columns Select a user coordinate system as shown in the figure above.


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A semi-micromechanic interlaminar strain analysis on curved-beam specimens Download PDF EPUB FB2

A Semi-Micromechanic Interlaminar Strain Analysis on Curved-Beam Specimens Duksung Joh Deparment of Mechanical and Aerospace Engineering and Engineering Mechanics University of Missouri-Rolla, RoHa b Missouri Final Report, April-December 31 under Grant NCC \ \ (NASA-CR-]_) A SEMI-MICROMFCHANIC.

Get this from a library. A semi-micromechanic interlaminar strain analysis on curved-beam specimens: final report, April-December 31 under grant NCC [Duksong Joh; United States. National Aeronautics and Space Administration.]. A semi-micromechanic interlaminar strain analysis on curved-beam specimens.

By Duksung Joh. Whole field contour maps of circumferential and interlaminar strains were obtained by using moire interferometry in a semi-micromechanic scale.

Various anomalous effects were observed in the displacement fields. the tensile interlaminar strain Author: Duksung Joh. When the applied load is identical, the face y-strain of the same R/t specimen decreases with increasing thickness, which means that the thicker specimen will bear higher loads.

Download: Download full-size image; Fig. Strain information of the laminated curved beam by:   Therefore, the curved beam strength is calculated according to the first peak load. The curved beam strength and equivalent interlaminar strength of the specimens are summarized in Table 1.

The average peak load was N with the average failure displacement of mm. Through the experimental observation and analysis, measurement of woven glass/polyester laminates using four-point curved beam specimen", Compos. Part A, 27(11), Joh, D.

(), "A semi-micromechanic interlaminar strain analysis on curved-beam specimens", NASA Contactor report-NASA CR; A semi-micromechanic interlaminar strain analysis on curved-beam specimens D Joh Model for interlaminar normal stress in doubly curved laminates Dissertation; Swiss Federal Institute of Technology.

The test setup and the same process to generate the ILT modulus values from the reduced-width coupons were identical to the regular ASTM D curved-beam coupons producing similar results.

Fig. 6 shows the ILT stress–strain response for the curved-beam coupons from the new batch. Table 3 lists the ILT modulus values. The average GPa (1. 1. Introduction. Components made of composite materials, incorporating zones of important bending radius are commonly present in a wide range of engineering structures, such as those found in aeronautics, the maritime industry and energy or civil main failure that takes place in these components results from poor Interlaminar Tensile Strength.

The fourth type of specimen involves variations of the curved beam test specimen sz-is, as shown in Figures IL TS of woven glass/polyester laminates: W.

Cui et al. Elliptical Circular Flat Figure 4 Semicircular or elliptical specimen13 (a) 1p r p 2P (b) P p Figure 5 Ring or curved beam specimensia   Interlaminar tensile strength (ILTS) measurement of woven glass/polyester laminates using four-point curved beam specimen Composites Part A: Applied Science and Manufacturing, Vol.

27, No. 11 Through-the-Thickness Tension Strength of. The analysis of curved specimens also showed A new data reduction method is developed for the curved specimens by adopting the Timoshenko curved beam theory. The book starts with. This work also expands the American Society for Testing and Materials Standard D curved-beam method as another means for measurement of the interlaminar tensile stress–strain.

Specimens with lower span-to-thickness ratios were found to yield higher apparent interlaminar shear strengths. This prediction coincides with many available experimental results. Journals. All Journals; Mechanical Engineering Magazine Select Articles; Applied Mechanics Reviews; ASCE-ASME Journal of Risk and Uncertainty in Engineering Systems, Part B: Mechanical Engineering.

Elastic interactions between the two arms of the specimen, asymmetry in geometry and lay-up, and interlaminar shear deformation are incorporated in the analysis. A Curved Beam Test Specimen for Determining the Interlaminar Tensile Strength of a Laminated Composite,” Analysis of Interlaminar Stresses in Viscoelastic Composites,” Ultra-High Strain Rate Constitutive Modeling of Pure Titanium Using Particle Impact Test.

e—indicated normal strain from strain transducer or extensometer. t12—shear stress on the plane perpendicular to the 1-axis that acts parallel to the 2-axis. t12 m—the calculated value of the t 12 shear stress taken at the lesser.

The created curved beam can rotate 90° about its system line. The half-axes of the ellipse will be denoted a and b. Among the options under 'Curved Beam Insertion', Choose 'Chord Offset(h)' and use mm (this is the distance of the center of the curve from the chord as shown in the diagram in the dialog box.

@article{osti_, title = {Static and fatigue interlaminar tensile characterization of laminated composites}, author = {Koudela, K L and Strait, L H and Caiazzo, A A and Gipple, K L}, abstractNote = {Spool and curved-beam specimens were evaluated to determine the viability of using either one or both of these configurations to characterize the static and fatigue interlaminar.

This test method is designed to produce through-thickness failure data for structural design and analysis, quality assurance, and research and development. Factors that influence the through-thickness tensile strength, and should therefore be reported, include the following: material and fabric reinforcement, methods of material and fabric preparation, methods of processing and specimen.

The weave pattern used during the weaving process can also affect the classification of 3D woven composites. For instance in the case of ORT weave, the frequency of the z-binder sweeping the top and bottom surfaces of the weave can vary from plain (Fig. 2a) to twill (Fig. 2b) or satin (Fig.

2c) will directly affect the unit-cell size, degree of crimp. The average specimen width and thickness w36 mm and 4,09 mm respectively, with very small differences between the specimens. The strains at failure averaged for all specimens were 20 ,78 microstrain at bottom and ,75 microstrain at the top of specimen.

This gives the strain ration of 1,4.