Download or read book Computer Simulation of Fast Crack Propagation and Arrest in Steel Plate with Temperature Gradient Based on Local Fracture Stress Criterion written by S. Machida and published by . This book was released on 1997 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: A fracture mechanics model for fast crack propagation and arrest is proposed based on the local fracture stress criterion. Dynamic fracture toughness (KD) for a propagating crack is calculated as a function of crack velocity and temperature. The model is extended to incorporate the effect of unbroken ligament (UL) formed near the plate surfaces and crack-front-tunneling. The model simulates acceleration, deceleration and arrest of a crack in a ESSO or a double-tension test plate with temperature-gradient. Calculated arrested crack lengths compare well with experimental results. It is shown that the conventional crack arrest toughness calculated from applied stress and arrested crack length depends on temperature-gradient and the toughness is not a unique material property.
Download or read book Fatigue and Fracture Mechanics written by John H. Underwood and published by ASTM International. This book was released on 1997 with total page 697 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fast Fracture and Crack Arrest written by George T. Hahn and published by ASTM International. This book was released on 1977 with total page 423 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Crack Propagation Tests of High strength Sheet Materials written by Cedric D. Beachem and published by . This book was released on 1960 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1987 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Preliminary Approaches to Experimental and Numerical Study on Fast Crack Propagation and Crack Arrest written by T. Kanazawa and published by . This book was released on 1977 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: Within the limit of relatively short arrested crack, static approximation by applying linear fracture mechanics has yielded useful results for theoretical interpretation and practical application of currently used brittle fracture propagation arrest test (the concept of arrest toughness). But later experimental investigations using very wide specimens (1300 to 2500-mm-wide plates) have revealed that this simple interpretation fails to have a consistency with the case of a long arrested crack. For the inadequacy of static approximation based on arrest toughness concept, the concept of an effective stress intensity factor has been introduced from a practical point of view without a clear quantitative explanation for it. In search of a more relevant theory for fast crack propagation and to see how the neglect of dynamic aspects affects the interpretation of unstable crack propagation arrest test and philosophy of crack arrest design, a dynamic fracture mechanics analysis was made with the use of the finite-difference method to solve the equation of motion for the two-dimensional elastic problem.
Download or read book Crack Arrest Methodology and Applications written by George T. Hahn and published by ASTM International. This book was released on 1980 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanics of Crack Arrest in Mild Steel written by Stanford University. Department of Materials Science and published by . This book was released on 1967 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dynamic K sub IC values for mild steel were measured using instrumented impact bend tests containing fatigued notches and compared with the stress intensity values in a Robertson crack arrest test. It is proposed that crack arrest occurs by the initial slowing down of the crack due to increased temperature which leads to a dramatic deceleration due to the large strain-rate sensitivity of the material. When the strain rate at the crack tip is maintained by dynamic loading which causes forced crack propagation, the crack will remain brittle to much higher temperatures than the crack arrest temperature. (Author).
Download or read book Fracture Analyses of Heavy Section Steel Technology Wide Plate Crack Arrest Experiments written by BR. Bass and published by . This book was released on 1988 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: A series of six wide-plate crack-arrest tests was recently completed by the Heavy-Section Steel Technology program at the National Bureau of Standards, Gaithersburg, MD, using tensile-loaded specimens of A533 Grade B Class 1 steel. Crack-arrest data were obtained at temperatures in the transition range and above the onset of the Charpy upper shelf, thereby providing a basis for the development and evaluation of improved fracture-analysis methods. The 1 by 1 by 0.102-m single-edge-notched (SEN) specimens were welded to long straight pull tabs and subjected to a transverse linear temperature gradient before loading. The crack tips were sharpened by hydrogen-charging an electron-beam weld. The tests were designed to obtain crack arrest near the middle of the specimen where the temperature would produce a high-toughness level in the upper transition region of the material. The specimens were instrumented with strain gages and thermocouples. Initial static design calculations were made using textbook formulas. Additional calculations, using an assumed set of KID versus ?a and T relations and an effective stress wave concept, confirmed the reasonableness of tentative design parameters. Pretest and posttest dynamic finite-element calculations were performed for each test. Computed results are compared with transient data for crack-line strains, crack speed, crack-opening displacement, arrest location, and postarrest tearing. Results from both application-mode and generation-mode dynamic analyses are presented. The arrest toughness values calculated from the test data are summarized for temperatures ranging from the transition into the Charpy upper-shelf range.
Download or read book Elevated Temperature Crack Growth written by and published by . This book was released on 1987 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Three Dimensional Variable Constraint Effects in Fracture Initiation written by and published by . This book was released on 1991 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many naturally occurring cracks are three dimensional and cannot be evaluated using numerical techniques derived using two dimensional simplifications. The high stress and strain levels experienced in modern high toughness alloys prior to fracture require means to accurately simulate the nonlinear response of ductile materials in this regime. An accurate constitutive representation must be combined with a fracture criterion which is valid for the high strain regime to achieve accurate computerized simulations of fracture and near fracture behavior. In the current work, nonlinear numerical simulations are performed to determine the global and local responses of two surface cracked plates of HY-100 steel with varying crack propagation and crack depths. Failure is defined by a local fracture criterion using strain energy density. Differences in constraint along the crack perimeter are taken into account by recognizing the stress-strain history dependence of the critical strain energy density. Crack growth patterns determined from the numerical simulations accurately reflect experimental observations.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 892 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Temperature Component Life Assessment written by George Webster and published by Springer Science & Business Media. This book was released on 1994-03-31 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of this book is to investigate and explain the rapid advances in the characterization of high temperature crack growth behaviour which have been made in recent years, with reference to industrial applications. Complicated mathematics has been minimized with the emphasis placed instead on finding solutions using simplified procedures without the need for complex numerical analysis.
Download or read book Fast Fracture Resistance and Crack Arrest in Structural Steels written by and published by . This book was released on 1973 with total page 129 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements and calculations of unstable fracture and fracture arrest in 12.7 mm- and 25.4 mm-thick, high-strength SAE4340 steel and A517F steel plates are described. A fully dynamic analysis of unstable crack propagation and arrest in the DCB (double cantilever beam)-test piece is derived. The technique is based on the beam-on-elastic-foundation model of the DCB specimen used previously but with the simple beam and foundation representations replaced by a Timoshenko beam and a generalized elastic foundation. Crack speeds, energy levels, and the crack length at arrest are calculated with this model using finite-difference method and are compared with the measurements. The kinetic energy imparted to the test piece is recovered and contributes to the crack driving force. It follows from this that fracture arrest is controlled by the history of energy dissipation throughout the entire propagation event, rather than on Ka, a single static toughness value calculated at the arrest point. (Modified author abstract).
Download or read book Computational Investigation of Local Material Strength and Toughness on Crack Growth written by V. G. DeGiorgi and published by . This book was released on 1990 with total page 51 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational simulation of stable crack growth is an important aspect of structural integrity prediction. Modern alloy strength and ductility increase local material fracture toughness but simultaneously complicates stable crack growth predictions. Material modeling, material parameter identification, fracture criterion and numerical crack growth algorithms are issues which must be addressed for robust stable crack growth prediction. In this investigation, a series of finite element simulations were undertaken to investigate two-dimensional Mode I crack growth in a modified compact tension specimen geometry. Two different crack lengths were considered. HY-100 steel parameters, previously characterized for large strain deformation, were utilized. Additional material responses, based on the HY-100 nonlinear response but with different yield strengths and ductilities, were also considered to parametrically assess material effects on crack growth. (JES).
Download or read book Computer Simulation of Linear and Nonlinear Crack Propagation in Cementitious Materials written by Túlio Nogueir Bittencourt and published by . This book was released on 1993 with total page 668 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of computer graphics is stressed not only to control the crack propagation process, but also to allow fast and comprehensive interpretation of results.
Download or read book Thermomechanical Crack Growth Using Boundary Elements written by N. N. V. Prasad and published by Computational Mechanics. This book was released on 1998 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermal and mechanical fatigue problems are encountered in many engineering components, such as pressure vessels, high temperature vessels, high temperature engines and interfaces in computer technology. This book describes the modelling of thermal fatigue using the Dual Boundary Element Method.
