Author: C. P. DebelPublisher:
ISBN:
Category : Steel
Languages : en
Pages : 17
Book Description
Experimental Evaluation of Brittle Crack Propagation Velocity
Author: C. P. DebelRisø-M.
Author: Proceedings of an international conference on Dynamic Crack Propagation
Author: George C. SihPublisher: Springer Science & Business Media
ISBN: 9401092532
Category : Science
Languages : en
Pages : 707
Book Description
The planning meeting for a conference on Dynamic Crack Propagation was held at M.LT. in February 1971 and attended by research workers from several industrial, governmental and academic organizations. It was felt that a more specialized meeting would provide a better opportunity for both U.S. and foreign researchers to exchange their ideas and views on dynamic fracture, a subject which is seldom emphasized in national or international fracture conferences. Dynamic crack propagation has been a concern to specialists in many fields: continuum mechanics, metallurgy, geology, polymer chemistry, orthopedics, applied mathematics, as well as structural design and testing. It impinges on a wide variety of problems such as rock breaking and earthquakes, pressure vessels and line pipes, comminution and the per formance of armament and ordnance, etc. Advances have been numerous, covering theories and experiments from both the microscopic and macro scopic points of view. Hence, the need for comparing the theoretical and experimental results and bridging the gaps between the atomistic and continuum approaches must be constantly emphasized. It also appeared that the overall problem of dynamic fracture could benefit from a con solidation of crack models proposed for the various types of materials: metals, ceramics, composites, rocks, glasses, polymers and biomaterials.
Dynamic Fracture
Author: K. Ravi-ChandarPublisher: Elsevier
ISBN: 0080472559
Category : Science
Languages : en
Pages : 265
Book Description
Dynamic fracture in solids has attracted much attention for over a century from engineers as well as physicists due both to its technological interest and to inherent scientific curiosity. Rapidly applied loads are encountered in a number of technical applications. In some cases such loads might be applied deliberately, as for example in problems of blasting, mining, and comminution or fragmentation; in other cases, such dynamic loads might arise from accidental conditions. Regardless of the origin of the rapid loading, it is necessary to understand the mechanisms and mechanics of fracture under dynamic loading conditions in order to design suitable procedures for assessing the susceptibility to fracture. Quite apart from its repercussions in the area of structural integrity, fundamental scientific curiosity has continued to play a large role in engendering interest in dynamic fracture problems In-depth coverage of the mechanics, experimental methods, practical applications Summary of material response of different materials Discussion of unresolved issues in dynamic fracture
Dynamic Fracture Mechanics
Author: Arun ShuklaPublisher: World Scientific
ISBN: 9814477737
Category : Technology & Engineering
Languages : en
Pages : 374
Book Description
Covering a wide variety of topics in dynamic fracture mechanics, this volume presents state-of-the-art experimental techniques and theoretical analysis on dynamic fracture in standard and exotic materials. Written by world renowned researchers, this valuable compendium contains eleven chapters on crack initiation, crack propagation, crack arrest, crack-stress wave interactions, and experimental, analytical and numerical methods in dynamic fracture mechanics.
Experiments to Test a Systems Analysis of Brittle Fracture
Author: G. T. HahnPublisher:
ISBN:
Category :
Languages : en
Pages : 8
Book Description
The aim of this program has been to simplify the complex problem of fracture of metals by a systems approach: for a given type or mode of failure, the basic simple parameters and mechanisms controlling failure are identified, these are treated individually by experiment and analysis, and the individual results are combined into a description of the failure process yielding predictions which can be checked by experiment. Except for the last portion of the program, the experiments were conducted on center cracked steel foils. In the earlier stages of work the analysis concentrated on predictions of the development of plasticity with loading and the conditions at which crack propagation begins. The work was then directed toward the problem of rapid crack propagation basing the analysis on previous results. The work has yielded a detailed description of crack propagation under plane stress conditions both in the form of an analytic model and experimental observations of crack speeds. A method for quantitatively measuring the energy absorption rate of a material during crack propagation has been tested. This method holds promise as a way of characterizing the intrinsic resistance to unstable crack propagation. Some of the concepts and methods developed have been applied to the very complex problem of calculating crack speeds in pipelines. (Author).
Slow Crack Growth of Brittle Materials with Exponential Crack-Velocity Formulation. Part 2; Constant Stress Rate Experiments
Author: National Aeronautics and Space Administration (NASA)Publisher: Createspace Independent Publishing Platform
ISBN: 9781721514205
Category :
Languages : en
Pages : 40
Book Description
The previously determined life prediction analysis based on an exponential crack-velocity formulation was examined using a variety of experimental data on glass and advanced structural ceramics in constant stress rate and preload testing at ambient and elevated temperatures. The data fit to the relation of strength versus the log of the stress rate was very reasonable for most of the materials. Also, the preloading technique was determined equally applicable to the case of slow-crack-growth (SCG) parameter n greater than 30 for both the power-law and exponential formulations. The major limitation in the exponential crack-velocity formulation, however, was that the inert strength of a material must be known a priori to evaluate the important SCG parameter n, a significant drawback as compared with the conventional power-law crack-velocity formulation. Choi, Sung R. and Nemeth, Noel N. and Gyekenyesi, John P. Glenn Research Center NASA/TM-2002-211153/PT2, NAS 1.15:211153/PT2, E-13009-2/PT2
Slow Crack Growth of Brittle Materials with Exponential Crack-Velocity Formulation. Part 3; Constant Stress and Cyclic Stress Experiments
Author: National Aeronautics and Space Adm NasaPublisher: Independently Published
ISBN: 9781723754739
Category : Science
Languages : en
Pages : 30
Book Description
The previously determined life prediction analysis based on an exponential crack-velocity formulation was examined using a variety of experimental data on advanced structural ceramics tested under constant stress and cyclic stress loading at ambient and elevated temperatures. The data fit to the relation between the time to failure and applied stress (or maximum applied stress in cyclic loading) was very reasonable for most of the materials studied. It was also found that life prediction for cyclic stress loading from data of constant stress loading in the exponential formulation was in good agreement with the experimental data, resulting in a similar degree of accuracy as compared with the power-law formulation. The major limitation in the exponential crack-velocity formulation, however, was that the inert strength of a material must be known a priori to evaluate the important slow-crack-growth (SCG) parameter n, a significant drawback as compared with the conventional power-law crack-velocity formulation.Choi, Sung R. and Nemeth, Noel N. and Gyekenyesi, John P.Glenn Research CenterCRACK PROPAGATION; BRITTLE MATERIALS; MECHANICAL PROPERTIES; HIGH TEMPERATURE; AMBIENT TEMPERATURE; PREDICTIONS; LIFE (DURABILITY); FAILURE; CYCLIC LOADS
Applied Mechanics Reviews
Author: Fracture Mechanics and Crack Growth
Author: Naman RechoPublisher: John Wiley & Sons
ISBN: 111856328X
Category : Technology & Engineering
Languages : en
Pages : 347
Book Description
This book presents recent advances related to the following two topics: how mechanical fields close to material or geometrical singularities such as cracks can be determined; how failure criteria can be established according to the singularity degrees related to these discontinuities. Concerning the determination of mechanical fields close to a crack tip, the first part of the book presents most of the traditional methods in order to classify them into two major categories. The first is based on the stress field, such as the Airy function, and the second resolves the problem from functions related to displacement fields. Following this, a new method based on the Hamiltonian system is presented in great detail. Local and energetic approaches to fracture are used in order to determine the fracture parameters such as stress intensity factor and energy release rate. The second part of the book describes methodologies to establish the critical fracture loads and the crack growth criteria. Singular fields for homogeneous and non-homogeneous problems near crack tips, v-notches, interfaces, etc. associated with the crack initiation and propagation laws in elastic and elastic-plastic media, allow us to determine the basis of failure criteria. Each phenomenon studied is dealt with according to its conceptual and theoretical modeling, to its use in the criteria of fracture resistance; and finally to its implementation in terms of feasibility and numerical application. Contents 1. Introduction. Part 1: Stress Field Analysis Close to the Crack Tip 2. Review of Continuum Mechanics and the Behavior Laws. 3. Overview of Fracture Mechanics. 4. Fracture Mechanics. 5. Introduction to the Finite Element Analysis of Cracked Structures. Part 2: Crack Growth Criteria 6. Crack Propagation. 7. Crack Growth Prediction in Elements of Steel Structures Submitted to Fatigue. 8. Potential Use of Crack Propagation Laws in Fatigue Life Design.