The role of delamination in strength, failure mechanism and hole size effect in open hole tensile tests on quasi-isotropic laminates

2009 ◽  
Vol 40 (4) ◽  
pp. 335-342 ◽  
Author(s):  
Michael R. Wisnom ◽  
Stephen R. Hallett
Keyword(s):  
Size Effect ◽  
Failure Mechanism ◽  
Tensile Tests ◽  
Hole Size ◽  
Strength Failure ◽  
Open Hole

Effects of ply thickness and 0°-layer ratio on failure mechanism of open-hole and filled-hole tensile tests of thin-ply composite laminates

2021 ◽  
pp. 114926
Author(s):  
Ryoma Aoki ◽  
Ryo Higuchi ◽  
Tomohiro Yokozeki ◽  
Kazuyuki Aoki ◽  
Shigekazu Uchiyama ◽  
...  
Keyword(s):  
Failure Mechanism ◽  
Composite Laminates ◽  
Tensile Tests ◽  
Open Hole

Size Effect Law and Critical Distance Theories to Predict the Nominal Strength of Quasibrittle Structures

2013 ◽  
Vol 65 (2) ◽  
Author(s):  
Pere Maimí ◽  
Emilio V. González ◽  
Narcís Gascons ◽  
Lluís Ripoll
Keyword(s):  
Size Effect ◽  
Structural Strength ◽  
Critical Distance ◽  
Cohesive Law ◽  
Nominal Strength ◽  
Critical Fracture ◽  
Open Hole ◽  
Cracked Structures ◽  
Nonuniform Stress Field

The design of structures with a nonuniform stress field is of great industrial interest. The ability of the size effect law and critical distance theories to predict the nominal strength of notched and open hole specimens is analyzed in the present paper. The results obtained with these methods are compared with the solution of the problem computed, taking into account the material cohesive law. A conclusion of this paper is that the role of the critical fracture energy in determining the structural strength is negligible, except in large cracked structures. For unnotched structures of any size and for small cracked structures, the key parameter is the initial part of the softening cohesive law. This allows us to define design charts that relate the structural strength to a specimen size normalized with respect to a material characteristic length.

On the role of tin underlays for the prevention of thermal grooving in thin gold films

1986 ◽  
Vol 44 ◽  
pp. 732-733
Author(s):  
Jin Young Kim ◽  
R. E. Hummel ◽  
R. T. DeHoff
Keyword(s):  
Thin Film ◽  
Free Surface ◽  
Grain Boundary ◽  
Beneficial Effect ◽  
Failure Mechanism ◽  
Failure Mechanisms ◽  
Distinct Advantage ◽  
Gold Films ◽  
Gold Thin Film

Gold thin film metallizations in microelectronic circuits have a distinct advantage over those consisting of aluminum because they are less susceptible to electromigration. When electromigration is no longer the principal failure mechanism, other failure mechanisms caused by d.c. stressing might become important. In gold thin-film metallizations, grain boundary grooving is the principal failure mechanism.Previous studies have shown that grain boundary grooving in gold films can be prevented by an indium underlay between the substrate and gold. The beneficial effect of the In/Au composite film is mainly due to roughening of the surface of the gold films, redistribution of indium on the gold films and formation of In2O3 on the free surface and along the grain boundaries of the gold films during air annealing.

Numerical analysis of the deep soil failure mechanism for perimeter pile groups

2022 ◽  
Vol 12 (1) ◽  
pp. 1-26
Author(s):  
M. Watford ◽  
J. Templeman ◽  
Z. Orazalin ◽  
H. Zhou ◽  
A. Franza ◽  
...  
Keyword(s):  
Finite Element ◽  
Failure Mechanism ◽  
Pile Groups ◽  
Deep Soil ◽  
Pile Spacing ◽  
Lateral Capacity ◽  
Soil Failure ◽  
Dimensional Finite Element ◽  
Group Configuration

In this paper, the lateral limiting pressure offered by the deep ‘flow-around’ soil failure mechanism for perimeter (ring) pile groups in undrained soil is explored using two−dimensional finite element modelling. A parametric study investigates the role of group configuration, pile−soil adhesion, group size, pile spacing and load direction on group capacity and corresponding soil failure mechanisms. The finite element output show that the plan group configuration (square or circular) has a negligible influence on lateral capacity for closely spaced perimeter pile groups. When compared to ‘full’ square pile groups with the same number of piles, the present results suggest that for practical pile spacing (≳ two pile diameters), perimeter groups do not necessarily increase capacity efficiency, particularly if the piles are smooth. Nevertheless, perimeter groups are shown to be characterized by both the invariance of their capacity to the direction of loading and their highly uniform load-sharing between piles, which are beneficial features to optimize design.

Experimental Analysis on Bond Behavior of GFRCM Applied on Clay Brick Masonry

2017 ◽  
Vol 747 ◽  
pp. 542-549
Author(s):  
Marianovella Leone ◽  
Valeria Rizzo ◽  
Francesco Micelli ◽  
Maria Antonietta Aiello
Keyword(s):  
Mechanical Performance ◽  
Tensile Tests ◽  
Brick Masonry ◽  
Test Results ◽  
Clay Brick ◽  
Hydraulic Lime ◽  
Bond Behavior ◽  
Existing Structures ◽  
Strength Failure ◽  
Hydraulic Lime Mortar

External bonded reinforcements (EBR), made by fibrous meshes embedded in a cementitious/hydraulic lime mortar, are getting a great deal of attention, mostly for strengthening, retrofitting and repair existing structures. In this context, the interest versus the FRCM (Fiber Reinforced Cementitious Matrix) is growing. The mechanical performance of these mortar-based reinforcements is not well known at the date and it needs to be investigated in terms of bond and tensile strength, strain and stiffness, in relation to the type of both substrate and fibers. The present work reports the results of an experimental study, still in progress, on different pre-cured GFRP grids embedded in inorganic matrices and applied on clay brick masonry. First, the mechanical properties of both pre-cured GFRP grid and GFRCM reinforcements were obtained through tensile tests. Then, the experimental investigation on bond behavior was carried out by direct shear bond test. The test results were collected and processed to evaluate bond strength, failure mode, load-slip relationship.

Thickness-Dependent Tensile Behavior of Cu-Mn Alloys under Different Dislocation Slip Modes

2019 ◽  
Vol 294 ◽  
pp. 104-110 ◽  
Author(s):  
Le Le Kang ◽  
Dong Han ◽  
Xiao Wu Li
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Size Effect ◽  
Uniform Elongation ◽  
Tensile Behavior ◽  
Dislocation Slip ◽  
Slip Mode ◽  
Planar Slip ◽  
Metallic Materials

To explore the role of dislocation slip mode playing in the size effect of mechanical behavior of metallic materials, the tensile behavior of Cu-5at.%Mn and Cu-20at.%Mn alloys with thickness (t) spanning from 0.1 to 2.0 mm is investigated. The results reveal that the yield strength σYS of Cu-5at.%Mn alloy displays an independence of thickness, whereas the ultimate tensile strength σUTS and the uniform elongation δ show an obvious size effect. The σUTS and δ first slightly decrease as t is reduced from 2.0 to 0.5 mm, but evidently drop when t is below 0.5 mm. A similar size effect is also exhibited in Cu-20at.%Mn alloy; however, the variation trend of “the smaller the weaker” in size effect can be weakened by the planar slip of dislocations occurring during the deformation of this alloy.

New Evidence on the Role of Size Effect in Determining the Pricing of Risk, Volatility Dynamics, and Economic Exposure of Firm Returns

2020 ◽  
Vol 9 (3) ◽  
pp. 1-25
Author(s):  
Faisal Khan ◽  
Sharif Ullah Jan
Keyword(s):  
Size Effect ◽  
Stock Returns ◽  
Firm Size ◽  
Research Study ◽  
Leverage Effect ◽  
Conditional Heteroskedasticity ◽  
Economic Factors ◽  
Monthly Data ◽  
New Evidence

This research study analyses the role of size effect in detecting the pricing of risk, various volatility dynamics, and economic exposure of firm returns on the Pakistani stock market by employing monthly data for the period from 1998 to 2018. Three generalized autoregressive conditional heteroskedasticity models were applied: GARCH(1,1) for capturing different volatility dynamics, GARCH-M for pricing of risk, and EGARCH for asymmetric and leverage effect. The findings of the study are as follows: Firstly, the authors untie that pricing of risk is subject to considerable variations with respect to firm size. Secondly, in the process of detecting whether the firm size matters in the case of asymmetry and leverage effect, they find that it is indeed the case. Thirdly, size effect plays a substantial role in determining various volatility dynamics. Finally, they uncover that economic factors affect stock returns differently based on firm size, signifying the role of size effect.

Superplasticity and Microstructure Evolution of Electrodeposited Nanocrystalline Nickel

2007 ◽  
Vol 551-552 ◽  
pp. 539-544 ◽  
Author(s):  
S. Ding ◽  
Kai Feng Zhang ◽  
Guo Feng Wang
Keyword(s):  
Grain Size ◽  
Strain Rate ◽  
Room Temperature ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Intergranular Cracking ◽  
Mean Grain Size ◽  
Electrodeposited Nickel ◽  
Superplastic Properties

Nanocrystalline pure nickel (nc-Ni) was produced by pulse electrodeposition and its superplastic properties at and above room temperature were investigated. The electrodeposited nickel has a narrow grain size distribution with a mean grain size of 70nm. Uniaxial tensile tests at room temperature showed that nc-Ni has a limited plasticity but high tensile strength up to 1GPa at strain rates between 10-5 and 10-2s-1. However, when the temperature increased to 420 and higher, test specimens showed uniform deformation and the elongation value was larger than 200%. A maximum elongation value of 380% was observed at 450°C and a strain rate of 1.67x10-3s-1, SEM and TEM were used to examine the microstructures of the as-deposited and deformed specimens. The results indicated that fracture was caused by intergranular cracking and most cracks were originated from the brittle oxide formed during the tensile test. Grain coarsening was observed in the deformed specimen. The role of temperature and strain on grain growth was evaluated by comparing the microstructure of deformed samples with that of samples statically annealed. Deformation mechanism was discussed based upon the deformed microstructure and strain rate jump tests.

Sign in / Sign up

Export Citation Format

Share Document