Crack Growth Analysis for a Cylindrical Shell Under Dynamic Loading

2006 ◽  
Author(s):  
Majid Mirzaei ◽  
Reza Karimi
Keyword(s):  
Crack Growth ◽  
Growth Analysis ◽  
Structural Response ◽  
Cylindrical Tube ◽  
Experimental Results ◽  
Fracture Parameter ◽  
Flexural Waves ◽  
The Finite Element Method ◽  
Dynamic Software ◽  
Detonation Loading

A cylindrical tube subjected to internal detonation experiences a traveling load that produces transient deformations. The resulting flexural waves in the tube wall can lead to high strains, which substantially exceed the equivalent static strains. This paper reports the growth analysis of a preexisting crack in a thin cylindrical tube using the finite element method. The numerical modeling of the structural response of the tube to detonation loading was performed using WARP3D, which is a nonlinear-dynamic software for crack modeling using FEM. The simulations were compared with experimental results from literature and also with the results obtained from an analytical model for elasto-dynamic response of cylindrical shells with finite length to internal detonation loading. The modeling of crack growth was also performed using WARP3D based on CTOA as the fracture parameter. The final part of the paper is devoted to comparisons between the numerical crack growth simulations and experimental results reported in the literature.

Simulation of Fatigue Crack Growth in a Detonation Tube

2006 ◽  
Author(s):  
Majid Mirzaei ◽  
Mehdi Salavatian ◽  
Hasan Biglari
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Analytical Model ◽  
Gaseous Detonation ◽  
Strain History ◽  
Flexural Waves ◽  
Detonation Tube ◽  
Cylindrical Tubes ◽  
Detonation Loading

Internal gaseous detonation in cylindrical tubes can cause pressure loadings that move at high speeds. The resulting flexural waves in the tube wall can lead to high strains, which may exceed the equivalent static strains by up to a factor of 4. This paper starts with a brief review of an analytical model for the transient dynamic response of cylindrical tubes with finite length to internal detonation loading. The formulation of this analytical model considers the effects of transverse shear and rotary inertia and also accounts for the effects of reflected waves. The strain history obtained from this model is used to predict the cyclic growth of a hypothetical preexisting crack in a detonation tube using the AFGROW software. The second part of the paper describes the numerical investigation of the whole process. A simulated detonation loading is applied and the resulting fatigue crack growth is modeled using the FRANC3D software and its boundary element solver. The results indicate that realistic fatigue life predictions for tubes subjected to internal detonation require the consideration of the entire spectrum of strain and stress fluctuations, including the reflected flexural waves.

Tire Cornering Simulation Using an Explicit Finite Element Analysis Code

1998 ◽  
Vol 26 (2) ◽  
pp. 109-119 ◽  
Author(s):  
M. Koishi ◽  
K. Kabe ◽  
M. Shiratori
Keyword(s):  
Finite Element Method ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Test System ◽  
Experimental Results ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Explicit Finite Element ◽  
Explicit Finite Element Analysis ◽  
Element Method

Abstract The finite element method has been used widely in tire engineering. Most tire simulations using the finite element method are static analyses, because tires are very complex nonlinear structures. Recently, transient phenomena have been studied with explicit finite element analysis codes. In this paper, the authors demonstrate the feasibility of tire cornering simulation using an explicit finite element code, PAM-SHOCK. First, we propose the cornering simulation using the explicit finite element analysis code. To demonstrate the efficiency of the proposed simulation, computed cornering forces for a 175SR14 tire are compared with experimental results from an MTS Flat-Trac Tire Test System. The computed cornering forces agree well with experimental results. After that, parametric studies are conducted by using the proposed simulation.

Guided Wave Acoustic Emission from Fatigue Crack Growth in Aluminium Plate

2006 ◽  
Vol 13-14 ◽  
pp. 23-28 ◽  
Author(s):  
C.K. Lee ◽  
Jonathan J. Scholey ◽  
Paul D. Wilcox ◽  
M.R. Wisnom ◽  
Michael I. Friswell ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Elastic Waves ◽  
Fatigue Cracks ◽  
Guided Wave ◽  
Experimental Results ◽  
Multiple Reflections ◽  
Alloy Plate

Acoustic emission (AE) testing is an increasingly popular technique used for nondestructive evaluation (NDE). It has been used to detect and locate defects such as fatigue cracks in real structures. The monitoring of fatigue cracks in plate-like structures is critical for aerospace industries. Much research has been conducted to characterize and provide quantitative understanding of the source of emission on small specimens. It is difficult to extend these results to real structures as most of the experiments are restricted by the geometric effects from the specimens. The aim of this work is to provide a characterization of elastic waves emanating from fatigue cracks in plate-like structures. Fatigue crack growth is initiated in large 6082 T6 aluminium alloy plate specimens subjected to fatigue loading in the laboratory. A large specimen is utilized to eliminate multiple reflections from edges. The signals were recorded using both resonant and nonresonant transducers attached to the surface of the alloy specimens. The distances between the damage feature and sensors are located far enough apart in order to obtain good separation of guided-wave modes. Large numbers of AE signals are detected with active fatigue crack propagation during the experiment. Analysis of experimental results from multiple crack growth events are used to characterize the elastic waves. Experimental results are compared with finite element predictions to examine the mechanism of AE generation at the crack tip.

Structural Response and Remaining Life of Damaged Composites

2015 ◽  
Vol 813-814 ◽  
pp. 106-110
Author(s):  
Dalbir Singh ◽  
C. Ganesan ◽  
A. Rajaraman
Keyword(s):  
Hybrid Approach ◽  
Experimental Studies ◽  
Structural Response ◽  
Material Behavior ◽  
Experimental Results ◽  
Life Assessment ◽  
Nonlinear Material ◽  
Remaining Life ◽  
Design Effectiveness ◽  
Remaining Life Assessment

Composites are being used in variety of applications ranging from defense and aircraft structures, where usage is profuse, to vehicle structures and even for repair and rehabilitation. Most of these composites are made of different laminates glued together with matrix for binding and now-a-days fibers of different types are embedded in a composite matrix. The characterizations of material properties of composites are mostly experimental with analytical modeling used to simulate the system behavior. But many times, the composites develop damage or distress in the form of cracking while they are in service and this adds a different dimension as one has to evaluate the response with the damage so that its performance during its remaining life is satisfactory. This is the objective of the present study where a hybrid approach using experimental results on damaged specimens and then analytical finite element are used to evaluate response. This will considerably help in remaining life assessment-RLA- for composites with damage so that design effectiveness with damage could be assessed. This investigation has been carried out on a typical composite with carbon fiber reinforcements, manufactured by IPCL Baroda (India) with trade name INDCARF-30. Experimental studies were conducted on undamaged and damaged specimens to simulate normal continuous loading and discontinuous loading-and-unloading states in actual systems. Based on the experimental results, material characterization inputs are taken and analytical studies were carried out using ANSYS to assess the response under linear and nonlinear material behavior to find the stiffness decay. Using stiffness decay RLA was computed and curves are given to bring the influence of type of damage and load at which damage had occurred.

Crack Growth Analysis of High-Pressure Equipment for Hydrogen Storage

2013 ◽  
Author(s):  
Z. Y. Li ◽  
C. L. Zhou ◽  
Y. Z. Zhao ◽  
Z. L. Hua ◽  
L. Zhang ◽  
...  
Keyword(s):  
High Pressure ◽  
Hydrogen Storage ◽  
Crack Growth ◽  
Growth Analysis ◽  
Model Material ◽  
Hydrogen Gas ◽  
Cycle Life ◽  
Cold Worked ◽  
Type 304 ◽  
Pressure Hydrogen

Crack growth analysis (CGA) was applied to estimate the cycle life of the high-pressure hydrogen equipment constructed by the practical materials of 4340 (two heats), 4137, 4130X, A286, type 316 (solution-annealed (SA) and cold-worked (CW)), and type 304 (SA and CW) in 45, 85 and 105 MPa hydrogen and air. The wall thickness was calculated following five regulations of the High Pressure Gas Safety Institute of Japan (KHK) designated equipment rule, KHKS 0220, TSG R0002, JB4732, and ASME Sec. VIII, Div. 3. We also applied CGA for four typical model materials to discuss the effect of ultimate tensile strength (UTS), pressure and hydrogen sensitivity on the cycle life of the high-pressure hydrogen equipment. Leak before burst (LBB) was confirmed in all practical materials in hydrogen and air. The minimum KIC required for LBB of the model material with UTS of even 1500 MPa was 170 MPa·m0.5 in 105 MPa. Cycle life qualified 103 cycles for all practical materials in air. In 105 MPa hydrogen, the cycle life by KIH was much shorter than that in air for two heats of 4340 and 4137 sensitive to hydrogen gas embrittlement (HGE). The cycle life of type 304 (SA) sensitive to HGE was almost above 104 cycles in hydrogen, while the cycle life of type 316 (SA and CW) was not affected by hydrogen and that of A286 in hydrogen was near to that in air. It was discussed that the cycle life increased with decreasing pressure or UTS in hydrogen. This behavior was due to that KIH increased or fatigue crack growth (FCG) decreased with decreasing pressure or UTS. The cycle life data of the model materials under the conditions of the pressure, UTS, KIH, FCG and regulations in both hydrogen and air were proposed quantitatively for materials selection for high-pressure hydrogen storage.

An Analysis of Conventional and Self-Aligned four Terminal Resistor Structures for The Determination of The Contact Resistivity from End Resistance Measurements

1986 ◽  
Vol 71 ◽  
Author(s):  
I. Suni ◽  
M. Finetti ◽  
K. Grahn
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Computer Model ◽  
Contact Resistivity ◽  
Experimental Results ◽  
The Finite Element Method ◽  
Model Based ◽  
A Value ◽  
And Diffusion

AbstractA computer model based on the finite element method has been applied to evaluate the effect of the parasitic area between contact and diffusion edges on end resistance measurements in four terminal Kelvin resistor structures. The model is then applied to Al/Ti/n+ Si contacts and a value of contact resistivity of Qc = 1.8×10−7.Ωcm2 is derived. For comparison, the use of a self-aligned structure to avoid parasitic effects is presented and the first experimental results obtained on Al/Ti/n+Si and Al/CoSi2/n+Si contacts are shown and discussed.

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