Validation of Dynamic Hardening Models with Taylor Impact Tests at High Strain Rates

2014 ◽  
Vol 626 ◽  
pp. 389-396 ◽  
Author(s):  
Ming Jun Piao ◽  
Chung Hee Park ◽  
Hoon Huh ◽  
Ik Jin Lee
Keyword(s):  
High Strain ◽  
Strain Rates ◽  
High Strain Rates ◽  
Impact Tests ◽  
4340 Steel ◽  
Tension Tests ◽  
Wide Range ◽  
Hardening Models ◽  
Taylor Impact ◽  
Cook Model

This paper is concerned with the hardening behavior of 4340 steel at high strain rates from 104s-1to 106s-1. Tension tests were conducted using Instron 5583, HSMTM and SHPB testing machines at a wide range of strain rate from 10-3s-1to 103s-1. Three different impact velocities were performed for the Taylor impact tests to evaluate the reliability of Johnson–Cook model, modified Johnson–Cook model, modified Khan–Huang model, and Lim–Huh model at high strain rates for 4340 steel.

INVESTIGATING THE INFLUENCE OF ENVIRONMENTAL CONDITIONING ON EPOXY RESINS AT QUASISTATIC AND HIGH STRAIN RATES FOR MATERIAL OPERATING LIMIT

2021 ◽  
Author(s):  
SAGAR M. DOSHI, SAGAR M. DOSHI, ◽  
NITHINKUMAR MANOHARAN ◽  
BAZLE Z. (GAMA) HAQUE, ◽  
JOSEPH DEITZEL ◽  
JOHN W. GILLESPIE, JR.
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Yield Stress ◽  
High Strain ◽  
Operating Conditions ◽  
Strain Rates ◽  
High Strain Rates ◽  
Stress Strain ◽  
Wide Range ◽  
Environmental Aging

Epoxy resin-based composite panels used for armors may be subjected to a wide range of operating temperatures (-55°C to 76°C) and high strain rates on the order of 103-104 s-1. Over the life cycle, various environmental factors also affect the resin properties and hence influence the performance of the composites. Therefore, it is critical to determine the stress-strain behavior of the epoxy resin over a wide range of strain rates and temperatures for accurate multi-scale modeling of composites and to investigate the influence of environmental aging on the resin properties. Additionally, the characterization of key mechanical properties such as yield stress, modulus, and energy absorption (i.e. area under the stress-strain curve) at varying temperatures and moisture can provide critical data to calculate the material operating limits. In this study, we characterize mechanical properties of neat epoxy resin, SC-15 (currently used in structural armor) and RDL-RDC using uniaxial compression testing. RDL-RDC, developed by Huntsman Corporation, has a glass transition temperature of ~ 120°C, compared to ~ 85°C of SC-15. A split Hopkinson pressure bar is used for high strain rate testing. Quasistatic testing is conducted using a screw-driven testing machine (Instron 4484) at 10-3 s-1 and 10-1 s-1 strain rates and varying temperatures. The yield stress is fit to a modified Eyring model over the varying strain rates at room temperature. For rapid investigation of resistance to environmental aging, accelerated aging tests are conducted by immersing the specimens in 100°C water for 48 hours. Specimens are conditioned in an environmental chamber at 76 °C and 88% RH until they reach equilibrium. Tests are then conducted at five different temperatures from 0°C to 95°C, and key mechanical properties are then plotted vs. temperature. The results presented are an important step towards developing a methodology to identify environmental operating conditions for composite ground vehicle applications.

Concrete behaviour in direct tension tests at high strain rates

2013 ◽  
Vol 65 (11) ◽  
pp. 660-672 ◽  
Author(s):  
Ezio Cadoni ◽  
George Solomos ◽  
Carlo Albertini
Keyword(s):  
High Strain ◽  
Strain Rates ◽  
High Strain Rates ◽  
Direct Tension ◽  
Tension Tests

Anand Viscoplasticity Model for the Effect of Aging on Mechanical Behavior of SAC305 Operating at High Strain Rate and High Temperature

2015 ◽  
Author(s):  
Pradeep Lall ◽  
Di Zhang ◽  
Jeff Suhling ◽  
David Locker
Keyword(s):  
High Temperature ◽  
High Strain ◽  
Operating Temperature ◽  
Uniaxial Stress ◽  
Strain Rates ◽  
High Strain Rates ◽  
Plastic Properties ◽  
Long Term Storage ◽  
Wide Range ◽  
Operational Life

Portable products such as smartphones and tablets stay in the powered on condition for a majority of their operational life during which time the device internals are maintained at higher than ambient temperature. Thus, it would be expected for interconnects in portable products to be at a temperature high than room temperature when subjected to accidental drop or shock. Furthermore, electronics in missile-applications may be subjected to high strain rates after prolonged period of storage often at high temperature. Electronics systems including interconnects may experience high strain rates in the neighborhood of 1–100 per sec during operation at high temperature. However, the material properties of SAC305 leadfree solders at high strain rates and high operating temperatures are scarce after long-term storage. Furthermore, the solder interconnects in simulation of product drop are often modeled using elastic-plastic properties or linear elastic properties, neither of which accommodate the effect of operating temperature on the solder interconnect deformation at high operating temperature. SAC305 solders have been shown to demonstrate the significant degradation of mechanical properties including the tensile strength and the elastic modulus after exposure to high temperature storage for moderate periods of time. Previously, Anand’s viscoplastic constitutive model has been widely used to describe the inelastic deformation behavior of solders in electronic components under thermo-mechanical deformation. Uniaxial stress-strain curves have been plotted over a wide range of strain rates (ε̇ = 10, 35, 50, 75 /sec) and temperatures (T = 25, 50, 75, 100, 125°C). Anand viscoplasticity constants have been calculated by non-linear fitting procedures. In addition, the accuracy of the extracted Anand constants has been evaluated by comparing the model prediction and experimental data.

A modified Johnson–Cook model for tensile flow behaviors of 7050-T7451 aluminum alloy at high strain rates

2015 ◽  
Vol 631 ◽  
pp. 214-219 ◽  
Author(s):  
Jin Qiang Tan ◽  
Mei Zhan ◽  
Shuai Liu ◽  
Tao Huang ◽  
Jing Guo ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
High Strain ◽  
Strain Rates ◽  
High Strain Rates ◽  
Cook Model

Validation of the Hardening Behaviors for Metallic Materials at High Strain Rate and Temperature by Using the Taylor Impact Test

2016 ◽  
Vol 715 ◽  
pp. 153-158
Author(s):  
Ming Jun Piao ◽  
Hoon Huh ◽  
Ik Jin Lee ◽  
Hyung Won Kim ◽  
Lee Ju Park
Keyword(s):  
Tensile Tests ◽  
Thermal Softening ◽  
Experimental Results ◽  
Uniaxial Tensile ◽  
Strain Rates ◽  
Metallic Materials ◽  
Softening Effect ◽  
Impact Tests ◽  
Wide Range ◽  
Taylor Impact

This paper is concerned with the validation of the dynamic hardening behaviors of metallic materials by comparing numerical and experimental results of the Taylor impact tests. Several uniaxial tensile tests are performed at different strain rates and temperatures by using three kinds of materials: 4130 steel (BCC); OFHC copper (FCC); and Ti6Al4V alloy (HCP). Uniaxial material tests are performed at a wide range of strain rates from 10−3 s−1 to 103 s−1. Moreover, tensile tests are performed at temperature of 25 °C and 200 °C at strain rates of 10−3 s−1, 10−1 s−1, and 102 s−1, respectively. A modified Johnson–Cook type thermal softening model is utilized for the accurate application of the thermal softening effect at different strain rates. The hardening behaviors of the three materials are characterized by comparing the seven sequentially deformed shapes of the projectile from numerical and experimental results of Taylor impact tests.

Temperature-Dependent Tension Plastic Deformation and Fracture Behavior of Ti-6.6Al-3.3Mo-1.8Zr-0.29Si Alloy at High Strain Rates

2014 ◽  
Vol 626 ◽  
pp. 115-120
Author(s):  
Jun Zhang ◽  
Qi Wei Zhang ◽  
Yang Wang
Keyword(s):  
Strain Rate ◽  
Titanium Alloys ◽  
High Strain ◽  
Impact Resistance ◽  
Strain Rates ◽  
Temperature Dependent ◽  
High Strain Rates ◽  
Tension Tests ◽  
Deformation And Fracture ◽  
Split Hopkinson

Titanium alloys have received great interest in the engineering applications requiring light weight and high impact resistance components. It is necessary to understand the mechanical properties of titanium alloys at high strain rates and various temperatures in the structural design. In the present paper, uniaxial tension tests at strain rates of 190, 500 and 1150s-1 and temperatures of 20, 150, 300°C are carried out using a modified split hopkinson tension bar system to investigate the effects of strain rate and temperature on tension behavior of the Ti-6.6Al-3.3Mo-1.8Zr-0.29Si alloy. Experimental results indicate that the alloy has the rate and temperature sensitivity and still keeps high strengths and toughness at temperature up to 300°C under high strain rate. SEM observations reveal that ductile fracture is the major fracture mode when the alloy is deformed at high strain rates.

Investigation of Deformation and Damage of Taylor Impact Test

2013 ◽  
Vol 395-396 ◽  
pp. 806-809
Author(s):  
Ying Li ◽  
Yu Wang ◽  
Xiao Bin Li ◽  
Wei Zhang
Keyword(s):  
Impact Test ◽  
High Strain ◽  
Impact Damage ◽  
Strain Rates ◽  
Velocity Impact ◽  
Numerical Tests ◽  
Impact Tests ◽  
Taylor Impact ◽  
Taylor Impact Test ◽  
Impact Damages

Taylor impact tests are used as experimental and numerical tests for determining the mechanical behavior of materials subjected to high strain rates. Taylor impact tests are numerically simulated in the velocity range from 150m/s to 250m/s. Deformations of different impact velocity; impact damages of the axis centre; and the reasons of impact damage are discussed in the numerical simulation of Taylor impact test.

scholarly journals Dynamic fracture of a dual phase automotive steel

2018 ◽  
Vol 183 ◽  
pp. 02047
Author(s):  
Sarath Chandran ◽  
Patricia Verleysen ◽  
Junhe Lian ◽  
Wenqi Liu ◽  
Sebastian Münstermann
Keyword(s):  
High Strain ◽  
Image Correlation ◽  
Fracture Mechanisms ◽  
Dual Phase ◽  
Strain Rates ◽  
High Strain Rates ◽  
Damage Initiation ◽  
Damage And Fracture ◽  
Wide Range ◽  
Stress States

Dynamic testing of sheet metals has become more important due to the need for more reliable vehicle crashworthiness assessments in the automotive industry. The study presents a comprehensive set of experimental results that covers a wide range of stress states on a dual phase automotive sheet steel. Split Hopkinson bar tensile (SHBT) tests are performed on dogbone shaped samples to obtain the plastic hardening properties at high strain rates. A set of purpose designed sample geometries comprising of three notched dogbone tension samples is tested at high strain rates to characterise the dynamic damage and fracture properties under well controlled stress states. The geometry of the samples is optimised with the aid of finite element analysis. During the tests, high speed photography together with digital image correlation are implemented to acquire full field measurements and to gain more insight into the localisation of strains at high strain rates. An experimental-numerical approach is proposed to effectively determine the fracture characteristics of the dual phase steel under extreme conditions. A modified Bai-Wierzbicki model is implemented to assess the damage initiation and subsequent failure. Additionally, the fracture mechanisms are studied utilizing scanning electron microscopy.

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