Predicting and analyzing X-rays to measure propellant crack propagation speed

1996 ◽  
Vol 12 (2) ◽  
pp. 310-314 ◽  
Author(s):  
R. A. Frederick ◽  
B. M. Williams ◽  
S. B. Farmer
Keyword(s):  
Crack Propagation ◽  
Propagation Speed ◽  
X Rays ◽  
Crack Propagation Speed

scholarly journals Crack propagation speed in ceramic during quenching

2018 ◽  
Vol 38 (7) ◽  
pp. 2879-2885 ◽  
Author(s):  
Yingfeng Shao ◽  
Boyang Liu ◽  
Xiaohuan Wang ◽  
Long Li ◽  
Jiachen Wei ◽  
...  
Keyword(s):  
Crack Propagation ◽  
Propagation Speed ◽  
Crack Propagation Speed

Effect of Contact between the Crack Faces on Crack Propagation

2013 ◽  
Vol 577-578 ◽  
pp. 61-64 ◽  
Author(s):  
Guido Dhondt
Keyword(s):  
Crack Propagation ◽  
Propagation Speed ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Contact Conditions ◽  
Contact Formulation ◽  
Positive Mode ◽  
Crack Propagation Speed ◽  
Crack Faces ◽  
Realistic Prediction

In mixed-mode crack propagation the crack faces frequently touch each other. The ensuing friction is expected to decrease the crack propagation speed. This effect is usually not taken into account, however, a realistic prediction of this effect may increase the calculated life and consequently increase the length of the inspection intervals. In this paper, penalty contact conditions are introduced in between the crack faces of the automatically generated mesh in a cyclic crack propagation. Special attention is given to the contact formulation and the area in which contact is defined. It is shown that the resulting crack propagation rate is significantly reduced by the introduction of friction provided that positive Mode-I is not significantly involved.

scholarly journals Arctic Linepipe With High Resistance to Crack Propagation and HIC

1996 ◽  
Author(s):  
Gregorio R. Murtagian ◽  
Guillermo L. Fitzsimons ◽  
Juan C. González ◽  
Irina S. Kotova ◽  
Nikoli I. Anenkov
Keyword(s):  
Crack Propagation ◽  
Large Diameter ◽  
Propagation Speed ◽  
Unstable Crack ◽  
Computer Data ◽  
Computer Data Acquisition ◽  
Hydrogen Induced Cracking ◽  
Crack Propagation Speed ◽  
Linepipe Steels ◽  
Work Done

Linepipe steels for sour, arctic and offshore applications, form a class of material by themselves. These linepipes are originated in the need to fulfill several special characteristics like adequacy for induction bending, toughness requirement at very low temperature to prevent a unstable crack propagation, and hydrogen induced cracking resistance. These kind of linepipes are produced through clean steel practice, resulting in a low residuals content and a low non metallic inclusions rating. It is also very important to get a fine and uniform microstructure to guarantee good performance under sour environments, arctic and offshore conditions. In the present paper, a practical test to assess fitness for service of special linepipes is presented. Two linepipes with diameters between 219 and 273 mm and Diameter/thickness (D/t) ratios from 10 to 20, intended for arctic service were studied. While linepipe of both large Diameter and D/t (above 50), have been studied, there has been very little work done for diameters below 420 mm and D/t ratios in the range of 10–20. Full scale burst tests at −40°C and −60°C were carried out under controlled conditions. Actual crack propagation speed during burst tests at temperatures below −60°C, was tracked through an oscilloscope-computer data acquisition system. Weldability and hydrogen induced cracking performances were also studied.

Development of a Pipe Rupture

1988 ◽  
Vol 110 (4) ◽  
pp. 451-456
Author(s):  
T. R. Best
Keyword(s):  
Experimental Data ◽  
Steady State ◽  
Crack Propagation ◽  
Liquid Water ◽  
Propagation Speed ◽  
Pipe Failure ◽  
Subcooled Liquid ◽  
Reaction Forces ◽  
Crack Propagation Speed

An approach to the problem of predicting reaction forces that can occur during pipe failure is provided. Use is made of experimental data measuring crack propagation speed to determine the pipe rupture forces. The results of this paper are for pipelines carrying subcooled liquid water, but may be applied to other fluids. The reaction forces during pipe failure are compared with steady-state values.

scholarly journals Study on the Fracture Behavior of Cracks Emanating from Tunnel Spandrel under Blasting Loads by Using TMCSC Specimens

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Bang Liu ◽  
Zheming Zhu ◽  
Ruifeng Liu ◽  
Lei Zhou ◽  
Duanying Wan
Keyword(s):  
Crack Initiation ◽  
Crack Propagation ◽  
Fracture Behavior ◽  
Propagation Speed ◽  
Propagation Path ◽  
Propagation Time ◽  
Dynamic Stress Intensity Factors ◽  
Inclination Angles ◽  
Crack Propagation Speed ◽  
Radial Cracks

Radial cracks may exist around tunnel edge, and these cracks may propagate and weaken tunnel stability under nearby blasting operations. In order to study the blast-induced fracture behavior of radial cracks emanating from a tunnel spandrel, a tunnel model containing a spandrel crack (TMCSC) with different inclination angles was proposed in this paper. Crack propagation gauges (CPGs) and strain gauges were used in the experiments to measure crack initiation moment and propagation time. Finite difference models were established by using AUTODYN code to simulate crack propagation behavior and propagation path. ABAQUS code was used to calculate dynamic stress intensity factors (SIFs). The results show that (1) crack inclination angles affect crack initiation angles and crack propagation lengths significantly; (2) critical SIFs of both mode I and mode II decrease gradually with the increase of the crack propagation speed; (3) the dynamic energy release rates vary during crack propagation; and (4) there are “crack arrest points” on the crack propagation paths in which the crack propagation speed is very small.

Spontaneous Crack Propagation Along Functionally Graded Bimaterial Interfaces

2006 ◽  
Author(s):  
Dhirendra V. Kubair ◽  
B. Bhanu-Chandar
Keyword(s):  
Crack Propagation ◽  
Material Property ◽  
Material Properties ◽  
Propagation Speed ◽  
Functionally Graded ◽  
Hardening Material ◽  
Property Variation ◽  
Material Inhomogeneity ◽  
Crack Propagation Speed ◽  
Mode 3

The effects of spatially varying the material properties on the mode-3 planar crack propagation characteristics are numerically investigated. The spectral scheme that is available for homogeneous materials is modified to account for the asymmetrically varying material properties. Crack propagation along the interface of a functionally graded bimaterial system has been simulated. A parametric study was performed by systematically varying the material inhomogeneity length scale independently in the two half-spaces. Our study indicated that softening type graded materials reduce the resistance to fracture, while a hardening material offers higher fracture resistance with increase in inhomogeneity. Only the transient phase of crack propagation speed was affected by the material property variation, irrespective of whether the material was hardening, softening or an asymmetric type. The crack always reached a quasi-steady-state velocity, which remained unaffected by the material property inhomogeneity.

CRACK PROPAGATION BEHAVIOR OF LATERALLY CONSTRAINED POLYMERS USED AS DIELECTRIC ELASTOMERS

2021 ◽  
Author(s):  
Dilshad Ahmad ◽  
Karali Patra ◽  
Mokarram Hossain ◽  
Amit Kumar
Keyword(s):  
Crack Propagation ◽  
Crack Tip ◽  
Propagation Speed ◽  
Dielectric Elastomers ◽  
Failure Behavior ◽  
Strain Rates ◽  
Propagation Behavior ◽  
Average Crack ◽  
Crack Propagation Speed ◽  
Crack Propagation Behavior

ABSTRACT Dielectric elastomer-based transducers are rapidly gaining importance with the syntheses of new polymers that can potentially be used as dielectric materials. However, these materials are always prone to fracture in the presence of cracks and flaws. Failures originate from flaws (or notches), and a complete fracture may take place due to the propagation of cracks. The present work investigates the crack propagation behavior of two popular polymers, VHB 4910 and Ecoflex, that are widely used as dielectric elastomers. In this case, tensile loadings in laterally constrained boundary conditions are considered. The average crack propagation speed for Ecoflex is higher than that for VHB, implying that Ecoflex will fail earlier than that of VHB under similar conditions. Moreover, with increasing notch lengths at a fixed strain rate, the average crack propagation speed decreases appreciably but becomes constant for comparatively larger notches. The results also conclude that the average crack propagation speed and normalized crack tip diameter remain higher for VHB than for Ecoflex for larger normalized notch lengths. It is observed that the average crack propagation speed increases with strain rates, whereas the normalized crack tip diameter is independent of strain rates. Experimental results obtained here will provide a useful comparative insight to understand the failure behavior of two polymers widely used as dielectric elastomers.

Sign in / Sign up

Export Citation Format

Share Document