scholarly journals Time Dependent Characteristics of Proposed Constitutive Equation Covering Wide Range of Strain at High Strain Rate.

1992 ◽  
Vol 41 (460) ◽  
pp. 23-27 ◽  
Author(s):  
Hidefumi DATE
Keyword(s):  
Constitutive Equation ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Time Dependent ◽  
Wide Range

High Strain-Rate Compressive Behavior and Constitutive Modeling of Selected Polymers Using Modified Ramberg-Osgood Equation

2014 ◽  
Vol 566 ◽  
pp. 80-85
Author(s):  
Kenji Nakai ◽  
Takashi Yokoyama
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Compressive Stress ◽  
Constitutive Modeling ◽  
High Strain ◽  
Strain Rates ◽  
Stress Strain ◽  
Strain Behavior ◽  
Least Squares Fit ◽  
Wide Range

The present paper is concerned with constitutive modeling of the compressive stress-strain behavior of selected polymers at strain rates from 10-3 to 103/s using a modified Ramberg-Osgood equation. High strain-rate compressive stress-strain curves up to strains of nearly 0.08 for four different commercially available extruded polymers were determined on the standard split Hopkinson pressure bar (SHPB). The low and intermediate strain-rate compressive stress-strain relations were measured in an Instron testing machine. Six parameters in the modified Ramberg-Osgood equation were determined by fitting to the experimental stress-strain data using a least-squares fit. It was shown that the monotonic compressive stress-strain behavior over a wide range of strain rates can successfully be described by the modified Ramberg-Osgood constitutive model. The limitations of the model were discussed.

Mechanical Properties of Doped Solder SAC-Q for High Strain Rate Testing at Extreme Surrounding Temperatures for 6 Months of Isothermal Aging

2021 ◽  
Author(s):  
Pradeep Lall ◽  
Vishal Mehta ◽  
Jeff Suhling ◽  
Ken Blecker
Keyword(s):  
High Temperature ◽  
High Strain Rate ◽  
Strain Rate ◽  
Isothermal Aging ◽  
High Strain ◽  
Thermal Exposure ◽  
Strain Rates ◽  
Strain Behavior ◽  
Wide Range ◽  
Electronic Parts

Abstract Electronic parts may often get exposed to high strains during shocks, vibrations and drop conditions in both commercial and defense applications. In addition, such electronic parts can often be simultaneously exposed to extreme surrounding temperatures between −65°C and 200°C after storage in non-climate-controlled conditions. Electronic equipment can be subjected to strain rates of 1 to 100 per second in shock and vibration. Many of the doped SAC soldering alloys in the electronic components, including SAC-Q, SAC-R, Innolot have found applications in long-term thermal exposure environments. Low temperature high strain-rate properties are needed to assure durability under high temperature storage followed by shock and vibration. There is scarcity of high strain-rate data on alloys exposed to high temperature aging operating at extreme low-temperatures and extremely-high temperatures. For this study, SAC-Q material was tested and analyzed at temperatures from −65°C to 200°C and at a strain rates of from 10 to 75 per second. Following the production and retrieval of the specimens, specimens were stored for isothermal aging for up to 6 months at 100°C temperature, before performing tensile test experiments at various operating temperatures. Stress vs strain curves are formed for the wide range of strain rates and surrounding temperatures. In addition, test results and data were complemented by the Anand viscoplasticity model and by calculating stress-strain behavior, evaluated in a wide range of working temperatures and strains rates.

Evaluation of Bodner-Partom Model Parameters at High Strain Rate

1986 ◽  
Vol 108 (1) ◽  
pp. 75-80 ◽  
Author(s):  
A. M. Rajendran ◽  
S. J. Bless ◽  
D. S. Dawicke
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Material Behavior ◽  
Model Parameters ◽  
Plate Impact ◽  
Plane Plate ◽  
Wide Range ◽  
Split Hopkinson ◽  
Stress States

The objective of this paper is to model the high strain rate material behavior of metals using Bodner-Partom visco-plastic constitutive model. A unique algorithm has been developed to evaluate the model parameters from the split Hopkinson Bar and plane plate impact tests data. The model parameters were successfully determined for the 6061-T6 aluminum, 1020 steel, and HY 100 steel. Using the evaluated model parameters, the test data obtained from an unusually wide range of stress states for these three metals were successfully modeled.

scholarly journals Intermediate Strain Rate Testing Devices

2020 ◽  
Author(s):  
Trunal Bhujangrao
Keyword(s):  
Experimental Data ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Full Range ◽  
Strain Rates ◽  
Intermediate Strain Rate ◽  
Wide Range ◽  
Rate Testing ◽  
Rate Test

The existing experimental tests are mainly designed to study the mechanical response of materials at various strain rates. Many researchers performed the experimental test in tension, compression, and shear (with torsion test) over a wide range of strain rates. They found out that material exhibits an increase in yield stress as well as flows stress with an increase in strain rate. It illustrates that there is a need for experimental data to study the material behaviour over the full range of strain rates, from quasi-static to high strain rate test. Many special techniques have been developed to bridge the strain rate gap between quasi-static and high strain rate testing to provide a method for an intermediate strain rate test for engineering materials. Some researchers have tried to conduct intermediate strain rate tests with standard servo-hydraulic load frames. However, the results of such tests are not accurate. The problem is that during the experiment, the whole machine is not in static equilibrium. The inertial effect influences the experimental data. The records obtained from these machines are often noisy with large oscillation. therefore, the comprehensive review is given to describes the development and evolution of the existing intermediate strain rate testing devices which includes the working principles, some critical theories, technological innovation in load measurement techniques, components of the device, basic technical assumption, and measuring techniques. In addition, some research direction on future implementation and development of an intermediate strain rate apparatus is also discussed in detail.

scholarly journals Processing, Microstructure and High Strain Rate Behaviour of Ti-6Al-4V Alloy Produced from a Blended Mixture Using Powder Compact Extrusion

2016 ◽  
Vol 704 ◽  
pp. 413-422 ◽  
Author(s):  
Ajit Pal Singh ◽  
Brian Gabbitas ◽  
Fei Yang ◽  
Rob Torrens
Keyword(s):  
Impact Toughness ◽  
High Strain Rate ◽  
Strain Rate ◽  
Powder Compact ◽  
High Strain ◽  
Axial Stress ◽  
Hot Extrusion ◽  
Vacuum Sintering ◽  
Wide Range ◽  
Quality Material

Powder compact extrusion (PCE) is an innovative way of processing titanium and titanium alloys to produce good-quality material with a wide range of compositions, microstructures and mechanical properties. This paper explores PCE processing of Ti-6Al-4V alloy prepared from a blended powder mixture, containing elemental hydride-dehydride (HDH) titanium powder and master alloy (60Al-40V) powder. The warm pressed compacts of blended powders were sintered using a vacuum sintering furnace prior to β extrusion. The resulting material was used to measure the performance under high strain rate and tri-axial stress state using Charpy v-notch testing. A comparison was made of the microstructure after vacuum sintering and hot extrusion in addition to oxygen measurements to determine the degree of oxygen pickup during each processing stage. A comprehensive study of fracture surfaces in selected samples was carried out using optical microscopy and scanning electron microscopy. Based on the results, it is clear that certain samples picked up varying amounts of interstitial impurities during processing and as a consequence a significant number of micro-cracks were observed in lamellar type microstructures. The oxygen content of all as-extruded samples was between 0.34-0.44 wt.% with resultant impact toughness in the range of 10-14 J. The best impact toughness attained for the lowest oxygen as-extruded rods was 20% lower than the literature values for wrought material. In terms of fracture behaviour, ductile dimples, cleavage facets and cracks passing through lamellar structures were observed in all samples. However, the quantity of these fracture features varied significantly in each sample.

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