Three-Dimensional Aspects of Fatigue Crack Closure in Surface Flaws in Polymethylmethacrylate Material PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Three-Dimensional Aspects of Fatigue Crack Closure in Surface Flaws in Polymethylmethacrylate Material PDF full book. Access full book title Three-Dimensional Aspects of Fatigue Crack Closure in Surface Flaws in Polymethylmethacrylate Material by AF. Grandt. Download full books in PDF and EPUB format.
Author: AF. Grandt Publisher: ISBN: Category : Crack opening displacement Languages : en Pages : 19
Book Description
An experimental investigation using a Newton interference method with a transparent polymethylmethacrylate (PMMA) to measure crack opening displacement and closure on surface flaw crack growth is described. Fatigue crack growth tests are conducted on rectangular plates loaded in bending using optical interferometry measurements to map the crack surface opening displacement profiles and define crack opening loads. Results are presented for an experiment of constant applied stress intensity factor along the crack face free surface. The crack opening displacement patterns and measured closure loads are found to be strongly influenced by the formation of a void internal to the crack surfaces.
Author: AF. Grandt Publisher: ISBN: Category : Crack opening displacement Languages : en Pages : 19
Book Description
An experimental investigation using a Newton interference method with a transparent polymethylmethacrylate (PMMA) to measure crack opening displacement and closure on surface flaw crack growth is described. Fatigue crack growth tests are conducted on rectangular plates loaded in bending using optical interferometry measurements to map the crack surface opening displacement profiles and define crack opening loads. Results are presented for an experiment of constant applied stress intensity factor along the crack face free surface. The crack opening displacement patterns and measured closure loads are found to be strongly influenced by the formation of a void internal to the crack surfaces.
Author: Publisher: ISBN: Category : Languages : en Pages : 239
Book Description
Inconsistent experimental results of fatigue crack closure studies over the past 15 years have caused recent investigators to conclude that the fundamental phenomena controlling the crack driving mechanisms are not understood. A major contributor to this misunderstanding is an inadequate understanding of the complex three-dimensional nature of closure. This is true for two-dimensional thru-the-thickness cracks as well as for three-dimensional part-thru surface cracks. To assess the three-dimensional influences of fatigue crack closure on the growth rate of surface flaws, an experimental investigation was conducted using a rectangular plate of polymethylmethacrylate (PMMA) material loaded in four-point bending. The use of transparent PMMA material and a Newton optical interferometer system with a laser light source provided the capability to simultaneously measure three-dimensional crack opening displacement (COD) profiles and closure loads (Pc1).
Author: AF. Grandt Publisher: ISBN: Category : Crack opening displacement Languages : en Pages : 27
Book Description
A series of fatigue crack growth experiments was conducted on a transparent polymer (PMMA) using a surface flaw geometry in bending. A Newton interferometric technique was used to measure crack opening displacements and closure for four different loading histories. Results are presented for conditions of constant applied stress-intensity factor along the crack face free surface, at the crack tip in the depth direction, for constant applied load range, and for a block loading sequence.
Author: A. F. Grandt Publisher: ISBN: Category : Languages : en Pages : 205
Book Description
This final report summarizes progress on a basic research effort to determine three-dimensional aspects of the relationship between applied load and fatigue crack face separation. The research was motivated by the well known crack closure phenomenon, which indicates that naturally occurring fatigue cracks are physical held shut (or propped open) at zero load, so that crack surfaces do not separate in a linear elastic manner. Although prediction of fatigue crack opening behavior is of fundamental importance to many aspects of crack growth, relatively little is known about the three-dimensional character of closure. The research employed experimental and numerical procedures to develop predictive techniques for this important aspect of crack closure. Optical interference was used to measure crack opening in transparent polymer specimens, along with conventional crack opening and back face strain techniques for measuring crack closure. A numerical algorithm was developed to predict opening loads in surface flawed plates, and was compared with the experimental results. Keywords: Crack propagation, Cracking(Fracturing).
Author: Walter G. Reuter Publisher: ASTM International ISBN: 080311284X Category : Fracture mechanics Languages : en Pages : 428
Book Description
From the symposium (on title) held in Sparks, Nevada, April 1988. Twenty-two peer-reviewed papers are divided into sections on models and experiments (monotonic loading), and fatigue crack growth. Areas addressed include the differences in constraint for 2-D through-thickness cracks and 3-D surface
Author: James M. Larsen Publisher: ISBN: Category : Aluminum alloys Languages : en Pages : 286
Book Description
An investigation was performed to study the effects of slip character and crack closure on the propagation of small fatigue cracks in titanium- aluminum alloys. The materials examined were solution-treated Ti-4Al and Ti-8Al, as well as aged Ti-8Al. The propagation of naturally initiated surface cracks of depths as small as 25 micrometers was compared with the behavior of large through-thickness cracks. An extensometer was used to monitor crack closure throughout the large crack tests, and the closure behavior of the small cracks was measured using a computerized laser interferometric displacement gage having a displacement resolution of 0.01 micrometer. The measurements of crack closure were used to compute an effective stress intensity factor range. In all three alloys and for all test conditions, which included a range of stress levels and stress ratios, small cracks propagated faster than large cracks subjected to an equivalent Delta K, and the small cracks propagated under conditions that were significantly below the large-crack threshold, Delta K(th). Although the character and distribution of slip in Ti-Al alloys may have a dramatic influence on fatigue crack initiation and on the propagation of large cracks, this effect was minimal for small cracks.
Author: Francis J. Pitoniak Publisher: ISBN: Category : Polymethylmethacrylate Languages : en Pages : 88
Book Description
Fatigue cracks were grown in compact tension specimens of polymethylmethacrylate, a transparent polymer which was used as a model for metals. Various peak overloads applied to the constant DeltaK baselines used produced changes in the baseline load crack growth rates. A study of the monochromatic light interference fringe patterns emanating from the fatigue cracks at zero load indicated that the crack surface were closed along the saw cut edge and on the free surface of the specimens. The crack surfaces were displaced in the interior of the specimen at zero load. Measurement of the crack opening displacements from the fringe patterns indicated that the crack surfaces opened on the free surface at approximately half the baseline load level for a stress ratio of approximately zero. This is in agreement with the Elber crack closure concept.
Author: AF. Grandt
Author: AF. Grandt
Author: Wolf Elber
Author: 
Author: AF. Grandt
Author: A. F. Grandt
Author: Walter G. Reuter
Author: James M. Larsen
Author: 
Author: 
Author: Francis J. Pitoniak