Author: University of Texas. Structural Mechanics Research LaboratoryPublisher:
ISBN:
Category : Strains and stresses
Languages : en
Pages :
Book Description
Stress-strain Characteristics of Materials at High Strain Rates: Strain-rate effects and plastic wave propagation
Author: University of Texas. Structural Mechanics Research LaboratoryPublisher:
ISBN:
Category : Strains and stresses
Languages : en
Pages :
Book Description
Stress-strain Characteristics of Materials at High Strain Rates
Author: James W. TurnbowStress-Strain Characteristics of Materials at High Strain Rates. Part III. Strain Rate Effects and Plastic Wave Propagation
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
The existing theories pertaining to the propagation through rods or wires of stresses exceeding the proportional limit are not in agreement with some aspects of experimental results. In order to resolve these differences, accurate dynamic stress-strain diagrams, obtained under conditions of constant strain rate, are especially required in order to establish the effect of strain rate upon the dynamic stress-strain law. A brief survey is made of the experimental techniques which have been employod in the past for measuring transient loads and strains aad for deducing the strain-rate effects. Based on the assumptions made in these previous methods and the results obtained from them, a direct method of recording simultaneously the stress-time and strain-time curves was chosen and impact tests were conducted on short, hollow cylinders of aluminum and copper at strain rates from 40 to 1600 in./in./sec. The method did not permit the establishing of complete stress-strain diagrams, but the ultimate stresses and elastic moduli were obtained and have been presented as functions of strain rate. The results of the experimental investigation show that: (1) The ultimate stress for 606l-T6 aluminum alloy cylinders increases approximately uniformly with increase in strain rate at about 5.4 psi per in./in./sec. (2) The ultimate stress for the copper increases from the static test value of 49,400 psi to 60,000 psi at a strain rate of 200 in./in./ sec. From this point, the stress then increases uniformly at about 4.5 psi per in./in./sec. (3) Great care must be taken to insure planeness of impact when the ratio of the length to diameter of the specimen is small; otherwise test results may vary widely. (4) The basic method used does not give the complete stress-strain diagram because of difficulties of interpretation of the test records in the vicinity of the elastic limit stress. (5) A second method, used for the 1600 in./in./sec strain rates, offers more promise for further development. (6) The effective elastic modulus, sigma / epsilon, of copper decreases with increase in strain rate. (auth).
Stress-strain Characteristics of Materials at High Strain Rates: The propagation of plastic waves in finite cylinders of strain-rate-dependent material
Author: University of Texas. Structural Mechanics Research LaboratoryPublisher:
ISBN:
Category : Strains and stresses
Languages : en
Pages :
Book Description
Materials at High Strain Rates
Author: T.Z. BlazynskiPublisher: Springer Science & Business Media
ISBN: 9781851660674
Category : Technology & Engineering
Languages : en
Pages : 326
Book Description
Metallurgical Effects at High Strain Rates
Author: R. RohdePublisher: Springer Science & Business Media
ISBN: 1461586968
Category : Technology & Engineering
Languages : en
Pages : 696
Book Description
A conference on Metallurgical Effects at High Strain Rates was held at Albuquerque, New Mexico, February 5 through 8, 1973, under joint sponsorship of Sandia Laboratories and the Physical Metallurgy Committee of The Metallurgical Society of AIME. This book presents the written proceedings of the meeting. The purpose of the conference was to gather scientists from diverse disciplines and stimulate interdisciplinary discussions on key areas of materials response at high strain rates. In this spirit, it was similar to one of the first highly successful con ferences on this subject held in 1960, in Estes Park, Colorado, on The Response of Metals to High Velocity Deformation. The 1973 conference was able to demonstrate rather directly the increased understanding of high strain rate effects in metals that has evolved over a period of roughly 12 years. In keeping with the interdisciplinary nature of the meeting, the first day was devoted to a tutorial session of invited papers to provide attendees of diverse backgrounds with a common basis of understanding. Sessions were then held with themes centered around key areas of the high strain rate behavior of metals.
Stress-Strain Characteristics of Materials at High Strain Rates. Part Iv. Experimental and Theoretical Analysis of Plastic Impacts on Short Cylinders
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
The effects of strain rate on the stress-strain characteristics of copper and lead were studied by measuring both stress and strain as functions of time using short cylindrical specimens supported at one end on a modified Hopkinson pressure bar and impacted at the other end by a steel projectile. Corresponding stresses and strains were computed according to an elementary nonstrain-rate theory (sometimes referred to as the von Karman theory) in which the dynamic stress-strain curve is assumed to be the same as the static stress- strain curve. Stresses and strains were also computed according to an elementary strain-rate theory (sometimes referred to as the Malvern theory) in which the dynamic stress may exceed the static stress for a given strain by an amount which depends upon the strain rate. It was found that the predictions of the nonstrain- rate theory agreed with measured values only for low impact velocities and for points at least two diameters from the impact end of the specimen. By proper choice of the flow or relaxation constant in the elementary strain-rate theory, measured and computed values of strain, or of stress, but not both simultaneously, could be brought into agreement. In the more general exponentialtype, strain-rate law, two independent parameters appear. Presumably with two constants to adjust, this theory could be made to correctly predict both stresses and strains for the conditions under which the tests were performed. If this procedure forces the theory to account for variations which are actually caused by lateral inertia and shear, erroneous conclusions regarding the properties of the material will be drawn. Further study of the effects of shear and lateral inentia is indicated. (auth).
STRESS-STRAIN CHARACTERISTICS OF MATERIALS AT HIGH STRAIN RATES. PART VI. THE PROPAGATION OF PLASTIC WAVES IN FINITE CYLINDERS OF STRAIN-RATE-DEPENDENT MATERIAL.
Author: Symposium on Dynamic Behavior of Material
Author: Foundations of Stress Waves
Author: Lili WangPublisher: Elsevier
ISBN: 0080470971
Category : Technology & Engineering
Languages : en
Pages : 549
Book Description
The primary objective of Foundations of Stress Waves is to give the reader an understanding of stress wave behaviour while taking into account the dynamic constitutive equations of elastic-plastic solids. The author has combined a 'materials characteristics' approach with a 'singularity surface' approach in this work, which readers will find to be a novel and unique route to solving their problems. Helps engineers understand the effects and behavior of stress waves in various materials Aids in the process of engineering design, testing, and evaluation