A Direct Correlation of Strength With Impact Velocity in the Taylor Test

1989 ◽  
Vol 111 (3) ◽  
pp. 327-330 ◽  
Author(s):  
P. P. Gillis ◽  
S. E. Jones
Keyword(s):  
Impact Velocity ◽  
Impact Test ◽  
Constitutive Law ◽  
Material Strength ◽  
Post Mortem ◽  
Specimen Length ◽  
Rate Dependent ◽  
Taylor Test ◽  
Undeformed Specimen ◽  
Taylor Impact

This paper presents a method for analyzing the results of a Taylor impact test. From post-mortem measurements of final specimen length and final undeformed specimen length the dynamic material strength on impact, σo, is correlated with impact velocity, V, through the relation σo=−Y−BV2 where Y and B are presumed to be material constants. This relation provides a rate-dependent constitutive law that is potentially useful in situations such as rod penetration, for example.

A Rate-Dependent Interpretation of the Taylor Impact Test

1989 ◽  
Vol 111 (4) ◽  
pp. 254-257
Author(s):  
S. E. Jones ◽  
P. P. Gillis ◽  
J. C. Foster ◽  
L. L. Wilson
Keyword(s):  
Yield Strength ◽  
Impact Velocity ◽  
Constitutive Relations ◽  
Material Constant ◽  
Constitutive Law ◽  
Material Strength ◽  
Rate Dependent ◽  
Post Test ◽  
Static Yield ◽  
Taylor Impact

A new one-dimensional theory for estimating the dynamic yield strength of materials, based on post-test measurements of Taylor impact specimens, has been developed by the authors. This theory offers the advantage of mathematical simplicity, while requiring only measurements of final specimen length, final undeformed length, and impact velocity as experimental data inputs. It is observed that the theory can accommodate a variety of material constitutive relations while preserving its basic simplicity. In particular, the dynamic material strength on impact, Y, can be directly correlated with impact velocity V through the relation Y = − Y0 − BV2. Here Y0 is the static yield strength and B is a material constant. This relation provides a rate-dependent constitutive law that is potentially useful in situations such as rod penetration, for example.

scholarly journals Load Characteristics in Taylor Impact Test on Projectiles with Various Nose Shapes

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 713
Author(s):  
Jun-Cheng Li ◽  
Gang Chen ◽  
Feng-Lei Huang ◽  
Yong-Gang Lu
Keyword(s):  
Impact Velocity ◽  
Impact Analysis ◽  
Impact Test ◽  
Impact Load ◽  
Loading Test ◽  
Impact Theory ◽  
Nose Shape ◽  
Taylor Impact ◽  
Taylor Impact Test ◽  
The Impact

This study focused on the impact load produced by a projectile and its potential application in the Taylor impact test. Taylor impact tests were designed and carried out for projectiles with four types of nose shapes, and the impact deformation characteristics and variation of the impact load as a function of the nose shape and impact velocity were studied. The overall high g loading experienced by the projectile body during the impact was discussed, and based on classical Taylor impact theory, impact analysis models for the various nose-shape projectiles were established and the causes of the different impact load pulse shapes were analyzed. This study reveals that the nose shape has a significant effect on the impact load waveform and pulse duration characteristics, while the impact velocity primarily affects the peak value of the impact load. Thus, the loading of specific impact environments could be regulated by the projectile nose shape design and impact velocity control, and the impact load could be simulated. Research results support the assumption that the Taylor impact test can be applied to high g loading test.

Optimizing material strength constants numerically extracted from taylor impact data

1997 ◽  
Vol 37 (3) ◽  
pp. 333-338 ◽  
Author(s):  
D. J. Allen ◽  
W. K. Rule ◽  
S. E. Jones
Keyword(s):  
Material Strength ◽  
Taylor Impact ◽  
Impact Data

Constitutive Response of Passivated Copper Films: Experiments and Analyses

2001 ◽  
Vol 695 ◽  
Author(s):  
Y.-L. Shen ◽  
U. Ramamurty
Keyword(s):  
Thermal Loading ◽  
Silicon Oxide ◽  
Kinematic Hardening ◽  
Copper Film ◽  
Temperature Response ◽  
Copper Interconnects ◽  
Constitutive Law ◽  
Copper Films ◽  
Rate Dependent ◽  
Constitutive Response

ABSTRACTThe constitutive behavior of passivated copper films is studied. Stresses in copper films of thickness ranging from 1000 nm to 40 nm, passivated with silicon oxide on a quartz or silicon substrate, were measured using the curvature method. The thermal cycling spans a temperature range from - 196 to 600°C. It is seen that the strong relaxation at high temperatures normally found in unpassivated films is nonexistent for passivated films. The copper film did not show any rate-dependent effect over a range of heating/cooling rate from 5 to 25°C/min. Further analyses showed that significant strain hardening exists during the course of thermal loading. In particular, the measured stress- temperature response can only be fitted with a kinematic hardening model, if a simple constitutive law within the continuum plasticity framework is to be used. The analytic procedures for extracting the film properties are presented. Implications to stress modeling of copper interconnects in actual devices are discussed.

Discrete-Direct Model Calibration and Uncertainty Propagation Method Confirmed on Multi-Parameter Plasticity Model Calibrated to Sparse Random Field Data

2021 ◽  
Vol 7 (2) ◽  
Author(s):  
Vicente J. Romero ◽  
Justin G. Winokur ◽  
George E. Orient ◽  
James F. Dempsey
Keyword(s):  
Strain Rate ◽  
Model Calibration ◽  
Structural Model ◽  
Uncertainty Propagation ◽  
Material Strength ◽  
Rate Dependent ◽  
Direct Model ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Force Displacement

Abstract A discrete direct (DD) model calibration and uncertainty propagation approach is explained and demonstrated on a 4-parameter Johnson-Cook (J-C) strain-rate dependent material strength model for an aluminum alloy. The methodology's performance is characterized in many trials involving four random realizations of strain-rate dependent material-test data curves per trial, drawn from a large synthetic population. The J-C model is calibrated to particular combinations of the data curves to obtain calibration parameter sets which are then propagated to “Can Crush” structural model predictions to produce samples of predicted response variability. These are processed with appropriate sparse-sample uncertainty quantification (UQ) methods to estimate various statistics of response with an appropriate level of conservatism. This is tested on 16 output quantities (von Mises stresses and equivalent plastic strains) and it is shown that important statistics of the true variabilities of the 16 quantities are bounded with a high success rate that is reasonably predictable and controllable. The DD approach has several advantages over other calibration-UQ approaches like Bayesian inference for capturing and utilizing the information obtained from typically small numbers of replicate experiments in model calibration situations—especially when sparse replicate functional data are involved like force–displacement curves from material tests. The DD methodology is straightforward and efficient for calibration and propagation problems involving aleatory and epistemic uncertainties in calibration experiments, models, and procedures.

EFFECT OF RELATIVE DENSITY AND VELOCITY TOWARDS DYNAMIC RESPONSE OF METAL FOAM

2015 ◽  
Vol 76 (9) ◽  
Author(s):  
Mohd Azman Y. ◽  
Juri S. ◽  
Hazran H. ◽  
NorHafiez M. N. ◽  
Dong R.
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Theoretical Prediction ◽  
Relative Density ◽  
Impact Velocity ◽  
Impact Test ◽  
Metal Foam ◽  
Element Analysis ◽  
Static Tests ◽  
The Impact

Dynamic response of ALPORAS aluminium foam has been investigated experimentally and numerically. The dynamic response is quantified by the force produced as the foam deforms as a function of time. Quasi-static tests are conducted to determine the quasi-static properties of the foam. In the impact test, the aluminium foams are fired towards a rigid load-cell and the force signals developed are recorded. Experimental dynamic stress is also compared with theoretical prediction using existing theory. Finite element model is constructed using LS-DYNA to simulate the impact test. Results from the experiment, finite element analysis and theoretical prediction are in acceptable agreement. Finally, parametric studies have been conducted using the verified model to investigate the effect of impact velocity and relative density towards the dynamic response of the foam projectile. It is found that the dynamic response of the foam is more sensitive towards impact velocity as compare with the foam relative density.

Modeling of Sleeved Taylor Impact Specimens

2003 ◽  
Author(s):  
William Keith Rule
Keyword(s):  
Stress State ◽  
Impact Test ◽  
Sliding Friction ◽  
Experimental Studies ◽  
Impact Testing ◽  
Strength Model ◽  
The Core ◽  
Post Test ◽  
Taylor Impact ◽  
Sliding Friction Coefficient

Recently experimental studies have been conducted using a novel form of the Taylor impact test consisting of sleeved cylinders. A soft material of known properties (OFHC Cu) was used for the core and the tight fitting sleeve was fabricated from the material of interest (AF1410 steel). On impact the mushrooming and sliding core places the sleeve in a stress state not normally found in Taylor impact testing. This paper describes a study conducted to evaluate the feasibility of backing out Johnson-Cook strength model coefficients from measured (post-test) deformed geometries of sleeved specimens using an explicit impact code (EPIC). In addition, modifications to the sleeved concept geometry (tapered and capped core) are also explored numerically as well as the sleeve/core sliding friction coefficient.

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