Analysis of dynamic mechanical behavior in reverse Taylor anvil-on-rod impact tests

Abstract

A one-dimensional analytical model has been developed for the reverse Taylor anvil-on-rod impact experiment to provide a method of extracting quantitative information from transient deformation states obtained from high-speed camera data. An indication of the plastic wave velocity and dynamic flow stress at varying locations and time are presented for two Cu OFE specimens impacted at 83 ± 1 and 205 ± 3 m/s. The results provide supporting evidence of previously reported "non-linear" and "quasi-steady" plastic wave propagation response, as well as a region of perfectly plastic behavior, which is independent of strain-rate in the higher impact velocity experiment. Additionally, the results show good agreement with the average value of dynamic yield stress calculated using Wilkins' analysis, based on a perfectly plastic material response. Furthermore, this work demonstrates the importance of careful design of Taylor impact experiments for * Corresponding author. Tel.: +1-404-894-2651. E-mail address: naresh.thadhani@mse.gatech.edu (N.N. Thadhani).2 minimizing measurement error and capitalizing on perfectly plastic response, for investigating the dynamic mechanical behavior of materials.

Dynamic response of reverse Taylor impact based on DIC technology

“…Eakins [8] adopted the analysis method similar to Taylor [1], an expression for the stress and strain was derived using the conservation equations of the elastic and elastic/plastic transition fronts. It should be noted that in all cases when conservation laws of mass and momentum are used, the equalities are performed between adjacent timeframes, rather than at a particular instance in time.…”

“…The original Taylor theory is no longer applicable and a new theory must be put forward for the reverse Taylor test. For the reverse test, Eakins et al [7,8] used the specimen outline data caught by high-speed camera to calculate the radius strain and plastic wave position on the direction of length. By developing the original Taylor theory, the flow stress along the rod was calculated by radius strain.…”

Determination of the Constants of Material Models Using Inverse Taylor Test

“…Johnson and Holmquist 24 examined the usefulness of Taylor test to determine the constants for various computational constitutive models such as the Johnson-Cook and Zerilli-Armstrong constitutive models. Eakins and Thadhani 25 have developed a one-dimensional analytical model for the reverse Taylor anvil-on-rod impact experiment to estimate the dynamic response of materials at high-strain rates. Their method is an extension to the method developed by Taylor 7 who has developed a theory for dynamic strength measurement from Taylor test about 60 years ago.…”

“…25 The value of the Gruneisen gamma was assumed as 0 = 2.12 (Ref. 25). Thermo-mechanical properties of copper used in this study are given in Table 3.…”

Dynamic deformation and fragmentation response of maraging steel linear cellular alloy

“…Flow boundaries were placed on the back surface and outer edges of the simulated anvil. The interface between the projectile and anvil was defined as frictionless, an appropriate approximation for these impact velocities [11]. Simulations were performed at 155 m/s and 306 m/s, and were terminated 50 μs after initial impact.…”