Plate Wave Characterization of Stiffness Degradation in Composites During Fatigue

Problems for load carrying elements reside mainly in buckling, embrittlement and corrosion. These problems can be mainly solved by introduction of composite materials of a sandwich type. These materials ally lightness, rigidity and resistance to the corrosion. For the design of a large number of applications, static and cyclic properties are necessary. In this paper, first static and fatigue tests on four points bending of four types sandwich panels have been performed. Load/displacement and S-N fatigue curves are presented and analysed. Fatigue failure and damage modes are observed with an electronic microscope and are discussed. Numerical simulation applied to the static tests is compared to the experimental results. The second is to address such fatigue behaviour by using a damage model and check it by experimentation. This fatigue damage model is based on stiffness degradation, which is used as a damage indicator. Four non-linear cumulative damage models derived from the chosen stiffness degradation equation are examined with assumption of linear Miner’s damage summation. Predicted results are compared with available experimental data.

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Design and characterization of micromachined piezoelectric acoustic flexural plate wave devices

2016 IEEE International Frequency Control Symposium (IFCS) ◽

10.1109/fcs.2016.7546803 ◽

2016 ◽

Cited By ~ 2

Author(s):

N. Weckman ◽

A. Seshia

Keyword(s):

Plate Wave ◽

Flexural Plate Wave

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Characterization of stiffness degradation caused by fatigue damage in textile composites using circumferential plate acoustic waves

Composites Science and Technology ◽

10.1016/j.compscitech.2008.02.031 ◽

2008 ◽

Vol 68 (7-8) ◽

pp. 1616-1623 ◽

Cited By ~ 21

Author(s):

S. Adden ◽

K. Pfleiderer ◽

I. Solodov ◽

P. Horst ◽

G. Busse

Keyword(s):

Fatigue Damage ◽

Acoustic Waves ◽

Textile Composites ◽

Stiffness Degradation ◽

Plate Acoustic Waves

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Morphological Characterization of Mycobacteriophage R1

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100051281 ◽

1974 ◽

Vol 32 ◽

pp. 254-255

Author(s):

B. L. Soloff ◽

T. A. Rado

Keyword(s):

Carbon Source ◽

Stationary Phase ◽

Growth Phase ◽

Minimal Medium ◽

Morphological Characterization ◽

Logarithmic Growth Phase ◽

Complete Lysis ◽

Lysogenic Culture ◽

Logarithmic Growth

Mycobacteriophage R1 was originally isolated from a lysogenic culture of M. butyricum. The virus was propagated on a leucine-requiring derivative of M. smegmatis, 607 leu−, isolated by nitrosoguanidine mutagenesis of typestrain ATCC 607. Growth was accomplished in a minimal medium containing glycerol and glucose as carbon source and enriched by the addition of 80 μg/ ml L-leucine. Bacteria in early logarithmic growth phase were infected with virus at a multiplicity of 5, and incubated with aeration for 8 hours. The partially lysed suspension was diluted 1:10 in growth medium and incubated for a further 8 hours. This permitted stationary phase cells to re-enter logarithmic growth and resulted in complete lysis of the culture.

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AEM analysis of crystallization in Ti-based amorphous alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100075142 ◽

1983 ◽

Vol 41 ◽

pp. 270-271

Author(s):

A.R. Pelton ◽

A.F. Marshall ◽

Y.S. Lee

Keyword(s):

Magnetic Properties ◽

Amorphous Alloys ◽

Amorphous Materials ◽

Isothermal Annealing ◽

Amorphous Matrix ◽

Nucleation And Growth ◽

Current Interest ◽

Amorphous Films ◽

Electrical And Magnetic Properties

Amorphous materials are of current interest due to their desirable mechanical, electrical and magnetic properties. Furthermore, crystallizing amorphous alloys provides an avenue for discerning sequential and competitive phases thus allowing access to otherwise inaccessible crystalline structures. Previous studies have shown the benefits of using AEM to determine crystal structures and compositions of partially crystallized alloys. The present paper will discuss the AEM characterization of crystallized Cu-Ti and Ni-Ti amorphous films.Cu60Ti40: The amorphous alloy Cu60Ti40, when continuously heated, forms a simple intermediate, macrocrystalline phase which then transforms to the ordered, equilibrium Cu3Ti2 phase. However, contrary to what one would expect from kinetic considerations, isothermal annealing below the isochronal crystallization temperature results in direct nucleation and growth of Cu3Ti2 from the amorphous matrix.

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Characterization of Coherent, Ordered Precipitates in Nickel-Base Alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100071168 ◽

1973 ◽

Vol 31 ◽

pp. 144-145

Author(s):

B. H. Kear ◽

J. M. Oblak

Keyword(s):

Stable Phase ◽

Nickel Base Superalloy ◽

Alloy 718 ◽

Commercial Alloy ◽

Precipitate Morphology ◽

Continuous Precipitation ◽

Nickel Base ◽

Base Superalloy ◽

Strengthening Precipitate

A nickel-base superalloy is essentially a Ni/Cr solid solution hardened by additions of Al (Ti, Nb, etc.) to precipitate a coherent, ordered phase. In most commercial alloy systems, e.g. B-1900, IN-100 and Mar-M200, the stable precipitate is Ni3 (Al,Ti) γ′, with an LI2structure. In A lloy 901 the normal precipitate is metastable Nis Ti3 γ′ ; the stable phase is a hexagonal Do2 4 structure. In Alloy 718 the strengthening precipitate is metastable γ″, which has a body-centered tetragonal D022 structure.Precipitate MorphologyIn most systems the ordered γ′ phase forms by a continuous precipitation re-action, which gives rise to a uniform intragranular dispersion of precipitate particles. For zero γ/γ′ misfit, the γ′ precipitates assume a spheroidal.

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