Download or read book Adiabaticity of High Strain Rate Compression Testing Using the Split Hopkinson Pressure Bar Apparatus microform written by Frank Stewart Walton and published by National Library of Canada = Bibliothèque nationale du Canada. This book was released on 1997 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Adiabaticity of High Strain Rate Compression Testing Using the Split Hopkinson Pressure Bar Apparatus written by and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Transient Dynamic Analysis of Modified Hopkinson Pressure Bar System for High Strain Rate Tensile Testing written by John-Paul Laurente Pascua and published by . This book was released on 2022 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: High strain rate testing of specimens within a split Hopkinson pressure bar (SHPB) is a well-established experimental technique used to quantify the compressive properties of materials in high impact events. The aim of this thesis is to investigate high strain rate tensile testing of materials utilizing a modified Hopkinson pressure bar system containing a tension yoke that deforms a test specimen by impacting the yoke strike plate and converting the incident compression wave into tension loading through the specimen. Credence towards the proposed design is built utilizing various finite element benchmark models and verification against the principles of SHPB systems is conducted using computational analysis to quantify the feasibility and performance of the system. Results show that the strain response in the Hopkinson pressure bar shows a strong correlation to the strain response in the test specimen, as assessed via comparison of peak forces and observing relatively low difference between the two quantities. Following this, effects of dispersion are explored further by modifying the impacting pulse shape and comparing results between different pulse shapes. Final stages of analysis reveal that momentum of the tension yoke largely affects the strain response of the tensile specimen relative to the applied pulse. However, the strong correlation of the force pulse developed within the tensile specimen and the force pulse transmitted into the Hopkinson bar remains very consistent, showing the potential of the proposed apparatus design to be used as a functional experimental system for converting impact into high strain rate tensile loading.

Download or read book New Experimental Techniques with the Split Hopkinson Pressure Bar written by and published by . This book was released on 1984 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The split Hopkinson pressure bar or Kolsky bar has provided for many years a technique for performing compression tests at strain rates approaching 104 s−1. At these strain rates, the small dimensions possible in a compression test specimen give an advantage over a dynamic tensile test by allowing the stress within the specimen to equilibrate within the shortest possible time. The maximum strain rates possible with this technique are limited by stress wave propagation in the elastic pressure bars as well as in the deforming specimen. This subject is reviewed in this paper, and it is emphasized that a slowly rising excitation is preferred to one that rises steeply. Experimental techniques for pulse shaping and a numerical procedure for correcting the raw data for wave dispersion in the pressure bars are presented. For tests at elevated temperature a bar mover apparatus has been developed which effectively brings the cold pressure bars into contact with the specimen, which is heated with a specially designed furnace, shortly before the pressure wave arrives. This procedure has been used successfully in tests at temperatures as high as 1000°C.

Download or read book A Microcomputer Based System for the High Speed Compression Test by the Split Hopkinson Pressure Bar Technique written by T. Yokoyama and published by . This book was released on 1986 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: A microcomputer-based system has been developed for the high-speed compression test by the split Hopkinson pressure bar technique. The present test system enables one to obtain reliable dynamic stress-strain data for materials for a very short period. The range of strain rates achieved by the test system is approximately 102 to 2 x 103 s-1 depending on the strength of the material and the impact velocity of a striker bar. The accuracy of the entire test system is checked directly by comparing the static and dynamic test results for a strain-rate insensitive material. Test results are presented for tough pitch copper and two aluminum alloys.

Download or read book High Strain Rate Testing Using the Torsional Split Hopkinson Bar written by Adam Sribniak (University of Manitoba student) and published by . This book was released on 2005 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Miniaturized Split Hopkinson Pressure Bar for Very High Strain Rate Testing written by and published by . This book was released on 2004 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements of material properties at very high rates of strain give an important insight into the structure of these materials, as well as having many industrial uses. This paper describes a miniaturized split Hopkinson pressure bar (MSHPB) for measuring the stress-strain relationships in materials at strain rates up to 105 s-1, extending the technique from its usual range of 500 - 104 s-1. As well as describing the difficulties of carrying out experiments at very high rates, and how these difficulties are overcome in this system, the paper also shows some data from experiments on copper and polytetrafluoroethylene (PTFE).

Download or read book Design and Operating Characteristics of a Split Hopkinson Pressure Bar Apparatus written by Kenneth D. Robertson and published by . This book was released on 1971 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Compression Testing by the Method of the Split Hopkinson Pressure Bar written by Barry Julius Kalinsky and published by . This book was released on 1965 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Split Hopkinson Pressure Bar Testing and Constitutive Model Evaluation for 7050 T7451 Aluminum IN718 Superalloy 300M Steel written by Xinlong Gao and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "The understanding of material's response to high strain rate loading is essential for a range of applications such as high-speed forming, machining, crashworthiness of automotive structures, and similarly ballistics impact performance of armor and engine fan blade containment structures. For reliable numerical modelling of such processes, accurate high strain rate materials data and constitutive models describing the strain rate dependence of the material's stress-strain response are necessary. The Split-Hopkinson pressure bar (SHPB) has been a commonly used method for evaluating the high strain rate response of materials in the range of 102s-1 to 104s-1. Measurements from this technique is useful for producing precise data to calibrate constitutive models, and to facilitate modeling and simulation of high strain rate processes.In this study, a compressive Split-Hopkinson pressure bar (SHPB) setup was used to evaluate the stress-strain response for three alloys, Aluminum 7050-T7451, Inconel 718, and 300M steel for the modelling of shot-peening, cold-work surface modification process. Shot peening involves impacting a material's surface with spherical media to generate sub-surface deformed layers containing strain hardening and residual stress. During the peening process, strain rates of the peened material can reach up to 105s-1 to 106s-1, which is greater than strain rates measurable using the SHPB. To enable a higher strain rate response, SHPB tests were carried out at a low temperature by cooling to represent the response of an increase in strain rate through the equivalent effect of lower temperatures and higher strain rates on the measured stress. In addition, SHPB tests were carried out at specific strain rates and test temperatures for calibrating constitutive models.From SHPB tests, Aluminum 7050-T7451 stress-strain results showed an increase in strain rate sensitivity above 103s-1 and at 25°C. For varying temperature tests measured at 2×103s-1, the stress-strain at -110°C showed higher strength and initial strain hardening rate compared to the resultat 25°C. Negative strain hardening occurred for results at 100°C and 200°C and the rate of thermal softening increased at 200°C. IN718 exhibited a moderate increase in strength from 103s-1 to 4×103s-1 at 25°C. For varying temperature tests at 4×103s-1, the strength increased at -110°C relative to 25°C and the strain hardening rate was comparable in both tests. At 500°C, the measured strain hardening rate was notably lower compared to the result at 25°C. 300M steel alloys tested at 3×10s-1 and 25°C displayed stress saturation and slight negative strain hardening with increasing strain. At a strain rate of 2.4×103s-1, the strength at -70°C was greater than that at 25°C, and strain hardening trends were similar for both conditions. Stress-strain response at 200°C displayed an initial increase in strain hardening prior to softening, and stress saturation at 500°C was comparable to the result at 25°C. In addition, shear failure occurred in samples tested at varying temperatures and strain to failure was comparable in all conditions.The SHPB results attained at high strain rates, varying temperatures as well as quasi-static data at 25°C, were used to evaluate the Johnson Cook (J-C) model parameter for each alloy. A modified Johnson Cook model with Voce strain hardening law and a modified Khan-Huang-Liang (KHL) model were evaluated and provided closer fit to Aluminum 7050-T7451 and IN718 results, respectively compared to the J-C model. For 300M steel, a modified J-C model with Cowper Symonds strain rate form provided comparable correlation to experiments as the J-C model. The J-C model, and models with more adequate correlations were used to extrapolate the stress at higher strain rates to represent the response encountered during peening." --

Download or read book Numerical Simulations of the Kolsky Compression Bar Test written by and published by . This book was released on 2015 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Kolsky compression bar, or split Hopkinson pressure bar (SHPB), is an ex- perimental apparatus used to obtain the stress-strain response of material specimens at strain rates in the order of 10 2 to 10 4 1/s. Its operation and associated data re- duction are based on principles of one-dimensional wave propagation in rods. Second order effects such as indentation of the bars by the specimen and wave dispersion in the bars, however, can significantly affect aspects of the measured material response. Finite element models of the experimental apparatus were used here to demonstrate these two effects. A procedure proposed by Safa and Gary (2010) to account for bar indentation was also evaluated and shown to improve the estimation of the strain in the bars significantly. The use of pulse shapers was also shown to alleviate the effects of wave dispersion. Combining the two can lead to more reliable results in Kolsky compression bar testing.

Download or read book High Strain Rate Testing with a Tri function Hopkinson Pressure Bar written by B. Nelain and published by . This book was released on 2007 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Design of a Split Hopkinson Bar Apparatus for Use with Fiber Reinforced Composite Materials written by Shawn M. Lang and published by . This book was released on 2012 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: PUBLIC ABSTRACT: Tabulated material properties are the starting block for the design of most structures. Mechanical structures undergo a wide range of loading conditions. Structures can be loaded statically or dynamically with a wide range of strain rates. With impact loading or high strain rates the relationships between stress and strain are not the same as in static loading. It has been observed that material properties are dependent upon the rate at which they are tested. Many investigators have studied the effect of high compressive strain rate loading conditions, in metals. The most common method for determining the dynamic response of materials is the Split Hopkinson bar, which can test materials at strain rates as high as 2000 s-1. The main focus of this work is to design a Split Hopkinson Bar apparatus to determine the dynamic compressive behavior of fiber reinforced composite materials. Graphite epoxy laminated composites have compressive failure strengths of 100 MPa. Dynamic compressive testing shows that the failure stress has increased to 260 MPa, an increase of approximately 230%. This testing shows that material properties are a function of the rate at which they are loaded.

Download or read book Construction Calibration and Application of a Split Hopkinson Pressure Bar written by Guojing Li and published by . This book was released on 2003 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The SNL Livermore Hopkinson Bar Apparatus for Compressive Materials Testing at High Strain rates written by W.A. Kawahara and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dynamic Compression Testing with Split Hopkinson Bar written by Charles N. Mann and published by . This book was released on 1966 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Dynamic Behavior of Hydrostatic pressure sensitive Materials at High Strain rates Based on Split Hopkinson Pressure Bar Technique written by Yubin Lu and published by . This book was released on 2010 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: