Metal Cutting as a Property Test

1967 ◽  
Vol 89 (3) ◽  
pp. 489-493 ◽  
Author(s):  
F. Lira ◽  
E. G. Thomsen
Keyword(s):  
Strain Rate ◽  
Metal Cutting ◽  
Effective Strain ◽  
Strain Rates ◽  
Rate Analysis ◽  
Cutting Test ◽  
Strain And Strain Rate ◽  
Conventional Tests ◽  
Strain Data ◽  
Cutting Speeds

It is suggested that a metal-cutting test can be utilized as a high-strain-rate property test at strains larger than those normally achievable in conventional tests. The strain and strain-rate analysis is performed on the chip root of a composite specimen whose interface records the necessary information in terms of deformed grid lines which become streamlines. In the stress analysis, it is necessary to assume that the shear stress calculated from transducer forces is constant throughout a thin shear zone observed at the higher cutting speeds. The results can be converted into effective-stress and effective-strain data and should permit the establishment of stress, strain rate, strain, and temperature relationships for materials at the larger strains and at the higher strain rates.

Comparison Analysis of Plastic Deformation in Metal Cutting with Cutting Simulation and Streamline Model

2011 ◽  
Vol 48-49 ◽  
pp. 323-326
Author(s):  
Xue Feng Bi ◽  
Cheng San Yang ◽  
Yu Lun Chi ◽  
Yong Xian Liu
Keyword(s):  
Plastic Deformation ◽  
Strain Rate ◽  
Metal Cutting ◽  
Test Point ◽  
Comparison Analysis ◽  
Point Tracking ◽  
Cutting Test ◽  
Strain And Strain Rate ◽  
Element Simulation ◽  
Deformation State

Strain and strain rate are two important parameters evaluating plastic deformation of workpiece in cutting process. Finite element simulation is implemented to estimate plastic deformation of wokrpiece in this paper. Flow net function in simulation is used to capture deformation state of grids on workpiece, and the deformation result is compared with that observed by Stevenson and Oxley in cutting test. Point tracking function in simulation is utilized to calculate strain and strain rate distribution along flow lines, and the results are also compared with that calculated by streamline model.

The effects of strain and strain rate on residual microstructures in copper

1986 ◽  
Vol 44 ◽  
pp. 420-421
Author(s):  
M. F. Stevens ◽  
P. S. Follansbee
Keyword(s):  
Strain Rate ◽  
Applied Stress ◽  
Threshold Stress ◽  
Rate Sensitivity ◽  
Viscous Drag ◽  
Strain Rates ◽  
Strain And Strain Rate ◽  
Threshold Strength ◽  
Mechanism Transition ◽  
Intrinsic Strength

The strain rate sensitivity of a variety of materials is known to increase rapidly at strain rates exceeding ∼103 sec-1. This transition has most often in the past been attributed to a transition from thermally activated guide to viscous drag control. An important condition for imposition of dislocation drag effects is that the applied stress, σ, must be on the order of or greater than the threshold stress, which is the flow stress at OK. From Fig. 1, it can be seen for OFE Cu that the ratio of the applied stress to threshold stress remains constant even at strain rates as high as 104 sec-1 suggesting that there is not a mechanism transition but that the intrinsic strength is increasing, since the threshold strength is a mechanical measure of intrinsic strength. These measurements were made at constant strain levels of 0.2, wnich is not a guarantee of constant microstructure. The increase in threshold stress at higher strain rates is a strong indication that the microstructural evolution is a function of strain rate and that the dependence becomes stronger at high strain rates.

Comparison of Two Complete Solutions in an Axisymmetric Extrusion With Experiment

1969 ◽  
Vol 91 (3) ◽  
pp. 543-548 ◽  
Author(s):  
A. H. Shabaik ◽  
E. G. Thomsen
Keyword(s):  
Strain Rate ◽  
Effective Strain ◽  
Cone Angle ◽  
Low Friction ◽  
First Approximation ◽  
Strain And Strain Rate ◽  
Conical Die ◽  
Stream Lines ◽  
Half Cone ◽  
Half Cone Angle

An upper-bound and a potential solution to a forward extrusion problem were compared with experimental results obtained by the visioplasticity method. The process consisted of extruding a 2-in-dia billet of preforged lead through a conical die having a half-cone angle of 45 deg under the condition of relatively low friction. The comparison was made for steady state stream lines, velocities, strain rate components, effective strain and strain rate, grid distortion, and stress distribution. It was found that the curves were generally of similar shape and that some differences existed in magnitude only. It is suggested that the theoretical solutions can be used to advantage to a first approximation in predicting all important variables.

Investigation of the axial compressive behavior of Kevlar fibers using the dynamic loop test

2019 ◽  
Vol 89 (18) ◽  
pp. 3825-3838
Author(s):  
Ahmad Abuobaid ◽  
Raja Ganesh ◽  
John W Gillespie
Keyword(s):  
Strain Rate ◽  
High Speed ◽  
Failure Strain ◽  
Kink Band ◽  
Test Method ◽  
Strain Rates ◽  
Compressive Failure ◽  
Band Formation ◽  
Rate Dependent ◽  
Strain And Strain Rate

A dynamic loop test method for measuring strain rate-dependent fiber properties was developed. During dynamic loop testing, the fiber ends are accelerated at constant levels of 20.8, 50 and 343 m/s2. The test method is used to study Kevlar® KM2-600, which fails in axial compression due to kink band formation. The compressive failure strain and strain rate at the onset of kink band formation is calculated from the critical loop diameter ( D C), which is monitored throughout the test using a high-speed camera. The results showed that compressive failure strain increases with strain rates from quasi-static to a maximum strain rate of 116 s−1 by a factor of ∼3. Kink angles (φ) and kink band spacing ( D S) were 60 ° ± 2 ° and 16 ± 3 μm, respectively, over the strain rates tested. Rate-dependent mechanisms of compressive failure by kink band formation were discussed.

Medium to High Strain-Rate Characterization of Lead Free Solder Alloys Through Metal Cutting Experiments

2019 ◽  
Author(s):  
Yuvraj Singh ◽  
Anirudh Udupa ◽  
Srinivasan Chandrasekar ◽  
Ganesh Subbarayan
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Metal Cutting ◽  
High Strain ◽  
Lead Free ◽  
Strain Rates ◽  
Lead Free Solder ◽  
Orthogonal Metal Cutting ◽  
Free Solder

Abstract Studies on medium to high strain-rate characterization (≥ 0.1s−1) of lead-free solder are relatively few, primarily due to the lack of available methods for testing. Prior work in literature uses Split Hopkinson Bar (SPHB) experiments for high strain-rate characterization (≥ 300s−1) [1,2], while a modified micro-scale tester is used for medium strain-rate characterization (0.005s−1 to 300s−1) [3] and an impact hammer test setup for testing in a strain-rate regime from 1s−1 to 100s−1 [4]. However, there is still limited data in strain-rate regimes of relevance, specifically for drop shock applications. In this paper, we present orthogonal metal cutting as a novel method to characterize lead-free solder alloys. Experiments are carried out using a wedgelike tool that cuts through a work piece at a fixed depth and rake angle while maintaining a constant cutting velocity. These experiments are conducted at room temperature on Sn1.0Ag0.5Cu bulk test specimens with strain-rates varying from 0.32 to 48s−1. The range of strain-rates is only limited by the ball screw driven slide allowing higher strain-rates if needed. The strains and strain-rates are captured through Particle Image Velocimetry (PIV) using sequential images taken from a high-speed camera just ahead of the cutting tool. The PIV enables non-contact recording of high strain-rate deformations, while the dynamometer on the cutting head allows one to capture the forces exerted during the cutting process. Results for the stress-strain response obtained through the experiments are compared to prior work for validation. Orthogonal metal cutting is shown to be a potentially attractive method for characterization of solder at higher strain-rates.

scholarly journals Dynamic Mechanical Characteristics and Constitutive Modeling of Rail Steel over a Wide Range of Temperatures and Strain Rates

2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Peijie Liu ◽  
Yanming Quan ◽  
Guo Ding
Keyword(s):  
Strain Rate ◽  
Mechanical Behavior ◽  
Split Hopkinson Pressure Bar ◽  
Rail Steel ◽  
Strain Rates ◽  
Dynamic Mechanical ◽  
Flow Response ◽  
Strain And Strain Rate ◽  
Average Absolute Relative Error ◽  
Wide Range

Rail steel plays an indispensable role in the safety and stability of the railway system. Therefore, a suitable constitutive model is quite significant to understand the mechanical behavior of this material. Here, the compressive mechanical behavior of heat-treated U71Mn rail steel over a wide range of strain rates (0.001 s−1–10000 s−1) and temperatures (20°C–800°C) was systematically investigated via uniaxial quasistatic and dynamic tests. The split Hopkinson pressure bar (SHPB) apparatus was utilized to perform dynamic mechanical tests. The effects of temperature, strain, and strain rate on the dynamic compressive characteristics of U71Mn were discussed, respectively. The results indicate that the flow response of U71Mn is both temperature-sensitive and strain rate-sensitive. However, the influence of temperature on the flow response is more remarkable than that of strain rate. On the basis of the experimental data, the original and modified Johnson-Cook (JC) models of the studied material were established, respectively. Using correlation coefficient and average absolute relative error parameters, it is revealed that better agreement between the experimental and predicted stress is reached by the modified JC model, which demonstrates that the modified one can characterize the mechanical behavior of the studied material preferably.

VERIFICATION OF THE SHB TEST RESULTS BASED ON THE ONE-DIMENSIONAL STRESS WAVE THEORY

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1068-1073
Author(s):  
TOMOKAZU MASUDA ◽  
KENJI SAITO ◽  
IZUMI MORITA ◽  
SHUSHI IKEDA ◽  
KOICHI MAKII ◽  
...  
Keyword(s):  
Strain Rate ◽  
Stress Wave ◽  
High Speed ◽  
Wave Theory ◽  
High Speed Photography ◽  
Strain Rates ◽  
One Dimensional ◽  
Strain And Strain Rate ◽  
Deformation Behaviors ◽  
The One

In order to evaluate dynamic deformation behaviors under high strain rates, Kobe Steel has developed and applied a Split-Hopkinson Bar (SHB) apparatus. This paper discusses the validity of the strain measurements and strain rates measured by this SHB apparatus. The strain waves that propagated in the incident and transmitted bars and the specimen are captured using a high-resolution type high-speed photography in detail. The strain wave propagated many times in the incident and transmitted bars and the specimen when the specimen was not broken. The amount of the deformation of the specimen decreases with the propagation frequency of the incident wave. On the other hand, to improve accuracy at the strain and strain rate calculated by the one-dimensional stress wave theory, Young's modulus, the longitudinal wave speed, and the density were accurately determined. It was understood that the calculation value showed the strain and strain rate captured with the high-speed photography are a good agreement. As a result, the validity of the measurement accuracy of this SHB could be shown.

scholarly journals Dynamic Shear Characteristic and Fracture Feature of Inconel 690 Alloy under Different High Strain Rates and Temperatures

2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
Tao-Hsing Chen ◽  
Chih-Kai Tsai ◽  
Te-Hua Fang
Keyword(s):  
Strain Rate ◽  
Shear Strain ◽  
High Strain ◽  
Rate Sensitivity ◽  
Shear Behaviour ◽  
Strain Rates ◽  
Dynamic Shear ◽  
Fracture Feature ◽  
Strain And Strain Rate ◽  
Inconel 690

The high strain shear rate behaviour of Inconel 690 alloy was investigated by using the split Hopkinson torsional bar. The shear strain rates were tested at 900 s−1, 1900 s−1, and 2600 s−1and at temperatures of −100°C, 25°C, and 300°C, respectively. It was found that the dynamic shear behaviour of Inconel 690 alloy was sensitive to strain rate and temperature. The fracture shear strain increased with increasing strain rate and temperature. In addition, the strain rate sensitivity was increased with increasing strain and strain rate but decreased with increasing temperature. Finally, the fracture surfaces were found to contain dimple-like features, and the dimple density increased with increasing strain rate and temperature.

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