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Friday, May 8, 2020 | History

3 edition of A mixed-mode bending apparatus for delamination testing found in the catalog.

A mixed-mode bending apparatus for delamination testing

John H. Crews

A mixed-mode bending apparatus for delamination testing

by John H. Crews

  • 118 Want to read
  • 37 Currently reading

Published by National Aeronautics and Space Administration, Langley Research Center in Hampton, Va .
Written in English

    Subjects:
  • Composite materials -- Delamination.

  • Edition Notes

    Other titlesMixed mode bending apparatus for delamination testing
    StatementJohn H. Crews, Jr. and James R. Reeder.
    SeriesNASA technical memorandum -- 100662
    ContributionsReeder, James R., Langley Research Center.
    The Physical Object
    FormatMicroform
    Pagination1 v.
    ID Numbers
    Open LibraryOL17096265M

    A modified mixed mode bending apparatus is designed and tested, which can be used to measure small forces involved in the delamination of semiconductor packaging materials. The mixed-mode bending (MMB) test was used to measure thc delamination toughness of a brittle epoxy composite, a state-of-the-arl toughened epoxy compos- ite, and a tough thermoplastic composite over the full mixed-mode range.

    James R. Reeder's 8 research works with citations and reads, including: A bilinear failure criterion for mixed-mode delamination Mixed-mode-bending delamination apparatus generates two. when the delamination tip is near either load point, simple closed form equations for GI and GII will not account for the complex effects of load concentrations or loading fixture stiffness. MIXED-MODE BENDING TEST The mixed-mode bending (MMB) test simply combines the mode I .

      The MMB test fixture is gaining popularity and is, today, the preferred method for quantifying the mixed-mode fracture toughness of composites, particularly now that ASTM D is available. The test specimen is simple and of a familiar form, and the test procedure is . Redesign of the mixed-mode bending delamination test to reduce nonlinear effects. This apparatus was demonstrated by measuring the mixed-mode delamination fracture toughhess of the test specimen. The nonlinearity errors associated with testing this tough composite material were less than +/- Author: James R. Reeder and Jr. John H. Crews.


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A mixed-mode bending apparatus for delamination testing by John H. Crews Download PDF EPUB FB2

A mixed-mode delamination test procedure was developed combining double cantilever beam (DCB) mode I loading and end notch flexure (ENF) mode II loading on a split unidirectional laminate.

By loading the specimen with a lever, a single applied load simultaneously produces mode I and mode II bending loads on the specimen. The mixed-mode bending test was first introduced by Crews and Reeder (Crews and Reeder, ; Reeder and Crews, ).

For the MMB test, the combination of Mode I and Mode II was limited by the testing apparatus, and the stress field is very complicated. purpose of this paper is to introduce a new test apparatus that can be used to measure delamination toughness over a wide range of A mixed-mode bending apparatus for delamination testing book I/II ratios as well as pure mode I and mode II.

First; the current methods for mixed-mode delamination testing will be briefly reviewed. Next, the proposed mixed-modeFile Size: KB.

this paper is rather simple and is believed to offer several advantages over most currentmixnt) test procedures Keyphrases delamination testing mixed-mode bending apparatus several advantage test.

Mixed-mode I–II–III delamination toughness determination via a shear–torsion-bending test Composites Part A: Applied Science and Manufacturing, Vol.

42, No. 6 Fracture toughness of a structural adhesive under mixed mode loadingsCited by: A MIXED-MODE BENDING APPARATUS FOR DELAMINATION TESTING John H. Crews, Jr. and James R. Reeder AUGUST National Aeronautics and Space Administration Langley Research Center Hampton, Virginia A mixed-mode delamination test procedure was developed combining double cantilever beam mode I loading and end notch flexure mode II loading on a split unidirectional laminate.

By loading the specimen with a lever, a single applied load simultaneously produces mode I and II Author: Jr. John H. Crews and James R. Reeder. In this article, the mixed-mode bending test appartaus was modified in order to reduce the influence of the weight of the lever on the mixed-mode fracture toughness during the by: For the mixed mode I + II, a mixed-mode bending apparatus was used.

The loading in this test is a simple combination of the double cantilever beam mode I and the end notch flexure mode II tests. In addition to characterisation of delamination initiation, whatever the value of the G II G T modal ratio, this apparatus allows the plotting of an R curve, from which we obtain the total fracture resistance, G Cited by: Delamination tests under three mixed I/II mode ratios were carried out via mixed mode bending test apparatus.

Significant R -curve effects on the fatigue crack growth rates and thresholds due to fiber bridging and crack branching were observed, which make the traditional Paris Law by: Full text of "Mixed-Mode Bending Method for Delamination Testing" See other formats Published in AIAA Journal, Vol Number 7, JulyPages — Mixed-Mode Bending Method for Delamination Testing James R.

Reeder* and John R. Crews Jr.** NASA Langley Research Center, Hampton, Virginia A mixed— mode delamination test procedure was developed combining. The exponent d increases as a function of Gn/G-r mode ratio with m, =wherease the coefficient ln(ß) versus Gii/G^ mode ratio decreases with m.ß = The parameters m^ and m/j seem to be characteristic of the material considered.

REFERENCES 1. Crews, J. and Reeder, J. R., A mixed mode bending apparatus for delamination by: Miniature Mixed Mode Bending apparatus This chapter is based on the paper, A Mixed Mode Bending apparatus for in-situ characterization of bi-material interface delamination, which is to be submitted.

Introduction The demands by the semiconductors industry for high levels of integra. The mixed mode bending test requires a specialised fixture and the use of a DCB type specimen, as detailed in Fig. The fixture is loaded as shown, and introduces both mode I and mode II loading into the specimen. The desired mode mixture is achieved by adjusting the distance, c, in accordance with.

A mixed mode delamination test procedure was developed combining double cantilever beam (DCB) mode I loading and end-notch fixture (ENF) mode II loading on a split unidirectional laminate. By loading with a lever, a single applied load simultaneously produces mode I and mode II bending loads on the specimen.

Propagation Option— In the MMB test, the delamination will grow from the insert in either a stable or an unstable manner depending on the mode mixture being tested. As an option, propagation toughness values may be collected when delaminations grow in a stable manner. Propagation toughness values are not attainable when the delamination grows in an unstable manner.

fracture resistance, GTR. For the mixed mode I + II, a mixed-mode bending apparatus was used. The loading in this test is a simple combination of the double cantilever beam mode I and the end notch flexure mode II tests.

In addition to characterisation of delamination. With the improved apparatus, loads are applied just above the midplane of the test specimen through a roller attached to the lever.

This apparatus was demonstrated by measuring the mixed-mode delamination fracture toughness of APC2. The nonlinearity errors associated with testing this tough composite material were less than ±3%.Cited by: A modified mixed-mode bending test apparatus was developed to measure delamination fracture toughness and fatigue delamination growth rates of laminated composites.

The test apparatus is compact, lightweight, and has very few by: A novel test frame configuration was developed and employed to design a new miniature mixed mode bending (MMMB) setup for in-situ characterization of interface delamination in miniature multi.

Get this from a library! A mixed-mode bending apparatus for delamination testing. [John H Crews; James R Reeder; Langley Research Center.].ratios using the Mixed-Mode Bending (MMB) Test.

This test method is limited to use with composites consisting of unidirectional carbon fiber tape laminates with brittle and tough single-phase polymer matrices.

This test method is further limited to the determination of fracture toughness as it initiates from a delamination insert. ThisFile Size: KB. J.H.

Chen R. Sernow G. Schulz G. Hinrichsen () ArticleTitle A modification of the mixed-mode bending test apparatus Composites Part A: Appl. Sci. Manufact. 30 – Occurrence Handle /SX(98)Cited by: