Experimental Study of the Effect of RCC Specimen Size and Crack Depth Ratio on Double-K Fracture Parameters

2014 ◽  
Vol 43 (2) ◽  
pp. 20140025 ◽  
Author(s):  
Xinzhuang Cui ◽  
Jiong Zhang ◽  
Fei Hou ◽  
Zhijun Gao ◽  
Zengtang Wang ◽  
...  
Keyword(s):  
Experimental Study ◽  
Crack Depth ◽  
Specimen Size ◽  
Depth Ratio ◽  
Fracture Parameters ◽  
Crack Depth Ratio

Experimental study of the crack depth ratio threshold to analyze the slow crack growth by creep of high density polyethylene pipes

2014 ◽  
Vol 122 ◽  
pp. 22-30 ◽  
Author(s):  
Lucien Laiarinandrasana ◽  
Clémence Devilliers ◽  
Jean Marc Lucatelli ◽  
Emmanuelle Gaudichet-Maurin ◽  
Jean Michel Brossard
Keyword(s):  
Experimental Study ◽  
Crack Growth ◽  
High Density Polyethylene ◽  
Slow Crack Growth ◽  
Crack Depth ◽  
High Density ◽  
Polyethylene Pipes ◽  
Depth Ratio ◽  
Crack Depth Ratio

Effect of Crack-Depth Ratio on Double-K Fracture Parameter of Reinforced Concrete

2012 ◽  
Vol 226-228 ◽  
pp. 937-941 ◽  
Author(s):  
Shao Wei Hu ◽  
Zheng Xiang Mi ◽  
Jun Lu
Keyword(s):  
Fracture Toughness ◽  
Reinforced Concrete ◽  
Crack Propagation ◽  
Crack Depth ◽  
Fracture Parameter ◽  
Propagation Process ◽  
Three Point Bending ◽  
Depth Ratio ◽  
Crack Propagation Process ◽  
Crack Depth Ratio

In order to study the influence of the crack-depth ratio on reinforced concrete fracture parameters and the resistance of the reinforcing bar to crack propagation in concrete, the fracture tests were carried on by using four groups three-point bending specimens with initial crack-depth ratios of 0.2, 0.3, 0.4 and 0.5 in this paper. An analytical model was presented to calculate fracture toughness of reinforced concrete by analyzing crack propagation process of the three-point bending beams. The formula of calculating effective crack length of reinforced concrete was established. The research results show that the double-K criterion can be used for describing crack propagation process of reinforced concrete by introducing fracture toughness, which is suitable for reinforced concrete. Initiation fracture toughness and unstable fracture toughness of reinforced concrete slowly increase with the increase of crack-depth ratio, which is different from the properties of ordinary concrete. The reinforced can improve the ductility of concrete obviously and inhibit the rate of crack propagation well.

Effect of Helix Angle on the Stress Intensity Factor of a Cracked Threaded Bolt

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
S. Suresh Kumar ◽  
Raghu V. Prakash
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Depth ◽  
Helix Angle ◽  
Mode Ii ◽  
Mode Iii ◽  
Aspect Ratios ◽  
Depth Ratio ◽  
Crack Depth Ratio

The fracture behavior of a crack in a threaded bolt depends on the stress intensity factor (SIF). Available SIF solutions have approximated the threaded bolt as a circular groove, thus, the SIF predominantly corresponds to the opening mode, mode-I. As a thread in a bolt has a helix angle, the crack propagates under mixed mode conditions (opening, sliding and tearing), esp. when the crack sizes are small. This paper presents the results of SIF solutions for a part-through crack emanating from a Metric threaded bolt. A 3D finite element model with preexisting flaws was generated to calculate the SIF values along the crack front. Crack aspect ratios in the range of (0.2 < (a/c) < 1) and crack depth ratios in the range of (0.1 < (a/d) < 0.5) (where “a” is crack length, “c” is semi major axis of ellipse and “d” is minor diameter of the bolt) were considered along the crack plane for the SIF estimation. The SIF values at the midregion decreases with an increase in aspect ratio (a/c), and SIF increases when the crack depth ratio (a/d) increases in the midregion. Close to the free edges, higher SIF values was observed for crack depth and aspect ratios ranging between 0.2 and 0.6 compared to midregion. In the crack surface region, up to a crack depth ratio of 0.25, significant influence of mode-II and mode-III fracture was noted for shallow cracks (a/c < 0.2). Significant influence of mode-II and mode-III fracture was observed for semicircular cracks (a/c = 1) beyond the crack depth ratio of 0.3.

Mixed Mode Stress Intensity Factor Determination for Single and Multiple Cracks in an Aircraft Wing

2014 ◽  
Vol 592-594 ◽  
pp. 2528-2533
Author(s):  
S. Suresh Kumar ◽  
V. Veeraraghavan ◽  
M. Vimalesh ◽  
Sanjay B. Bharadwaj
Keyword(s):  
Lift Force ◽  
Residual Life ◽  
Fatigue Cracks ◽  
Crack Depth ◽  
Bottom Surface ◽  
Multiple Cracks ◽  
Aircraft Wing ◽  
Aspect Ratios ◽  
Depth Ratio ◽  
Crack Depth Ratio

Structural failure of aircraft wings due to nucleation and propagation of cracks is one of the main reasons for failure of aged aircrafts. Reported studies on aircraft failures indicate that the main cause of wing failure is due to fatigue cracks which nucleate from the wing root region. Thus, determination of residual life of the cracked wing structure using fracture mechanics approach becomes important. In the present work an attempt has been made to estimate the SIF of single and multiple cracks in an aircraft wing subjected to lift force. Crack depth ratios ranging between 0.1 and 0.4 and aspect ratios of 0.6 and 1.0 have been considered. Single and multiple cracks are introduced at the wing rib region and the lift force is applied at the bottom surface of the wing. Geometric correction factor (Y) is estimated with the additional consideration of mode II and mode III fracture. The effect of crack depth ratio and number of cracks on SIF is determined. Non symmetric SIF distribution is observed with increase of crack depth ratio. It is also noted that SIF values are always higher at the crack surface region compared to crack middle region irrespective of crack depth ratio.

Experimental investigation of helical gear tooth crack location and depth detection using moving average method on transmission error

2021 ◽  
pp. 146442072110237
Author(s):  
Mohsen Rezaei ◽  
Mehrdad Poursina ◽  
Ehsan Rezaei
Keyword(s):  
Average Method ◽  
Gear Tooth ◽  
Moving Average ◽  
Crack Depth ◽  
Helical Gear ◽  
Crest Factor ◽  
Crack Location ◽  
Depth Ratio ◽  
Crack Depth Ratio ◽  
Gear Systems

Gear systems are the most useful and essential power transmission systems in the high-speed industry due to their accuracy. It is necessary to make sure that these systems work without defects such as tooth cracks. Therefore, detecting the location and depth of cracks in gear systems is very important. In this research, a new approach is proposed to detect the crack location, and accordingly, some statistical indicators are used to estimate the crack depth in the helical gear tooth. To this end, after explaining the helical gear mesh stiffness and tooth-root crack modeling, the helical gear pair dynamic is modeled. Then, the vibration data of a helical gear system is obtained by an experimental test rig, and the moving average method is undertaken to precisely detect the crack location. The crack depth ratio is estimated using the crest factor, impulse factor, clearance factor, and [Formula: see text] and [Formula: see text] which are applied to the simulation results and the experimental signal. According to these results, the crest factor, impulse factor, and clearance factor calculated the crack depth ratio with a good agreement, and the indicators [Formula: see text] and [Formula: see text] estimated it with a more significant error. Also, the average of estimated values is calculated, indicating a better result than each indicator alone.

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