scholarly journals The effect of disbond on the efficiency and durability of a composite patch repair in mode I and mixed mode considering different patch materials

2022 ◽  
Vol 30 ◽  
pp. 096739112110627
Author(s):  
Sirvan Mohammadi
Keyword(s):  
Growth Rate ◽  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Mixed Mode ◽  
Patch Repair ◽  
Mode I ◽  
Composite Patch ◽  
Repair Patch ◽  
The Mean ◽  
Patch Edge

In this paper, considering different parameters and various patch materials, the effect of disbond on the efficiency and durability of a composite patch repair is investigated in mode I and mixed-mode. One of the most important aspects of the composite patch repair is the bond strength. Repair patch disbond may occur at the patch edges or the crack site. At first, the effect of different parameters such as repair patch material and Young’s modulus and thickness of the adhesive on the efficiency and durability of the patch is investigated. Then, the effect of the disbond site on the stress intensity factor (patch efficiency) and adhesive stress (patch durability) is analyzed in both modes I and II. The results show that disbond at the crack site leads to a further reduction in patch efficiency compared to the patch edge disbond, but when separation occurs at the patch edge, the adhesive stress and the disbond growth rate are higher. Also, when 15% of the patch is separated in the crack site, for the longitudinal and transverse disbond modes, the mean KI is increased by 8 and 4%, respectively, compared to the state without disbond. Thus, the longitudinal disbond mode is more critical.

scholarly journals Experimental Evaluation on Mixed Mode I/II Stress Intensity Factors using CTS welded and non-welded specimen of Aluminum Alloy AA3003

2021 ◽  
Vol 9 (9) ◽  
pp. 1259-1265
Keyword(s):  
Stress Intensity Factor ◽  
Aluminum Alloy ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Mixed Mode ◽  
Pure Shear ◽  
Compact Tension ◽  
Shear Mode ◽  
Mode I ◽  
Intensity Factors

In the present paper, experimental investigation on the fracture of aluminum alloy AA3003 are conducted on the Compact Tension Shear CTS specimen non-welded and CTS specimen welded by FSW process under mixed mode loading by using Arcan loading device based on Richard’s principle suitable for mixed mode. All loading in mixed mode starting from pure tension (mode I) up to pure shear (mode II) can be obtained and tested by varying the loading angles from 0° to 90°. The stress intensity factor for the Compact Tension Shear (CTS) specimen are determined three normalized lengths cracks 0.3, 0.5 and 0.7.The length of notches influence on the variation of stress intensity factor KI, KII. For CTS specimen with notches with a short length, the values of KII are greater than those obtained for notches with a long length.

scholarly journals Evaluation of inclined crack in mixed mode I and II

2021 ◽  
Vol 9 ◽  
Author(s):  
Mohamed Tahar Hannachi ◽  
◽  
Mohamed Bradji ◽  
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Mixed Mode ◽  
Critical Energy ◽  
Mode I ◽  
Inclined Crack ◽  
Ductile Rupture ◽  
Treated Steel ◽  
Mode Of Failure

In this work,we tented to study the mixed mode of failure with two angles of inclination, of a treated steel, for that we tried to determine the parameters of failure as the stress intensity factor, tenacity and the critical energy in mixed mode of a rupture and see the criterion of rupture and seeing the effect of the angles evolution applied for all parameters. of in our close there is a fragile and less ductile rupture.

The boundary element method for analysing repair patches on cracked finite sheets

1988 ◽  
Vol 92 (920) ◽  
pp. 416-421 ◽  
Author(s):  
A. Young ◽  
D. J. Cartwright ◽  
D. P. Rooke
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Boundary Element Method ◽  
Intensity Factor ◽  
Boundary Element ◽  
Intensity Factors ◽  
Central Crack ◽  
Repair Patch ◽  
Patch Edge ◽  
Element Method

Summary The boundary element method is combined with the method of compatible deformations to obtain stress intensity factors for a cracked sheet reinforced with a repair patch. The method is applied to the analysis of a circular patch over a central crack in a rectangular uniaxially stressed sheet. It is shown that the proximity of the edges of the sheet to the patch edge has a negligible effect on the stress intensity factor of a crack completely under the patch.

Interference Effect of Interaction Cracks Investigated by Photoelastic and Caustics Methods

2005 ◽  
Vol 297-300 ◽  
pp. 1939-1944
Author(s):  
Tsutomu Ezumie ◽  
Kenya Ueno
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Crack Length ◽  
Mixed Mode ◽  
Material Strength ◽  
Mode I ◽  
Single Crack ◽  
K Value ◽  
Mode Change ◽  
Caustics Method

The crack, which occurs because of fatigue, should often consider not only the single crack but also plural cracks occurring. In this paper, the material strength when two or more cracks occurred because of fatigue etc. was examined by calculating stress intensity factor K value by using caustics method and the photoelasticity. In general, plural cracks are known KI value decreases compared with the single crack. Therefore, the influence on K value was experimentally examined from the point of the distance between the cracks, the angle, and the crack length and the mode change. As a result, KI value influences destruction in plural in exist only mode I and the mixed mode of mode I and mode Ⅱ like this research cracks. When the crack length becomes long if the distance between the cracks narrows, the decrease of KI value grows. In addition, it has been understood that the decrease of KI value is influenced by a/w on the boundary of d/a=1 (the distance between the cracks is equal to the crack length).

Numerical Analysis of Asymmetrically Bonded Composite Patch Repair and Effect of In-Plane Skewed Crack Front on the SIF

2017 ◽  
Vol 30 ◽  
pp. 11-22 ◽  
Author(s):  
Baltach Abdelghani ◽  
Aid Abdelkarim ◽  
Abdelkader Djebli ◽  
Belabbes Bachir Bouiedjra ◽  
Benhamena Ali
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Growth ◽  
Crack Front ◽  
Patch Repair ◽  
Growth Stages ◽  
Initial State ◽  
Element Analysis ◽  
Composite Patch

A nonlinear 3-D finite element analysis was conducted to analyze the crack front behavior of a center cracked aluminum plate, asymmetrically repaired with composite patch. According to experimental observations, the crack front was modeled as an inclined shape from the initial state where the crack front is straight and parallel to the thickness direction from the patched side toward the un-patched side. The skew degree is found to strongly influence the stress intensity factor (SIF) distribution along the crack front. In effect, the obtained trends of the SIF’s distribution are different and changes during crack growth stages. The main finding is that regardless the crack front shape (inclination), the average stress intensity factor through the crack front remains constant and consequently, it means to be an effective parameter to estimate the fatigue life and crack growth of the asymmetrically patched structures. The performed models gave good results compared to the literature and the different findings correlate well with the experimental observations and make sense with a realistic crack development.

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