ENGINEERING TRANSACTIONS
ROZPRAWY INŻYNIERSKIE
A QUARTERLY JOURNAL
- F. Pursche, L.W. Meyer:
Correlation between dynamic material behavior and adiabatic shear phenomenon for quenched and tempered steels
- R. Winzer, A. Glinicka:
The static and dynamic compressive behaviour of selected aluminium alloys
- E. Cadoni, A.M. Bragov, M. Dotta, D. Forni, A. Konstantinov, A. Lomunov, A. Ripamonti:
Mechanical characterization of steel for fastening in a wide range of strain rate
- P. Szeptyński:
Some remarks on Burzyński's failure criterion for anisotropic materials
- F. Pursche, L.W. Meyer:
Correlation between dynamic material behavior and adiabatic shear phenomenon for quenched and tempered steels
- Besides the common failure mechanism based on crack propagation, adiabatic shear failure
results from a collapse mechanism, mainly at high deformation rates. This failure incorporates
locally extreme high shear strains, but due to the small volume involved, it transpires in
a macroscopic brittle manner. This paper deals with the description of the influence of material
properties on adiabatic shear failure. In the literature, much information can be found, which
supports the theory that some material properties influence the occurrence of adiabatic shear
failure behavior in a positive or negative manner. The determination of propensity for the
investigated steels was done through special biaxial dynamic compression-shear-test in a drop
weight tower. The failure achieved in the test is only material-dependent. Furthermore, it
was found, that the theory of Culver with the competing processes of work hardening and
thermal softening is transferable on the tested materials in a qualitative manner. Additionally,
it was determined that few material properties have a strong controlling effect on the adiabatic
shear failure behavior and it is possible to determine a critical value for transition between
sheared and non sheared areas. Moreover, it could define a functional correlation of the failed
materials to certain properties. As a main result, the most important material property is the
dynamic compression behavior at high temperature. The stress level of the material and the
characteristic in dependence of temperature is decisive. Analytical considerations using high
temperature behavior patterns confirm this influence. Additionally, hardness and strength at
room temperature and the pure shear capability (hat-shaped specimen) are also important for
the evaluation of adiabatic failure behavior.
Contents
- R. Winzer, A. Glinicka:
The static and dynamic compressive behaviour of selected aluminium alloys
- The mechanical properties of structural aluminium alloys EN AW-5083 and EN AW-6082
in the 'H111' and 'T6' conditions, respectively, subjected to compressive loadings in the quasi-static and dynamic strain rate regimes, are investigated. Both alloys are used as structural
components not only in car body design or ship building, but also in civil engineering. Therefore, compression tests at room temperature were conducted using a servohydraulic Instron
machine, in order to determine the materials' behaviour at low and intermediate rates of deformation. In addition, to predict the dynamic response of these materials, the Split Hopkinson
Pressure Bar (SHPB) technique was utilized. For alloy 5083-H111, a changeover from negative
to positive strain rate sensitivity at dynamic strain rates is observable, whilst alloy 6082-T6
exhibits a mild trend towards positive strain-rate sensitivity. Furthermore, the coefficients of
the Johnson-Cook model, that are valid under dynamic conditions, are determined. The finite
element simulation of SHPB experiments shows that the constitutive model represents the
materials' behaviour quite well.
Contents
- E. Cadoni, A.M. Bragov, M. Dotta, D. Forni, A. Konstantinov, A. Lomunov, A. Ripamonti:
Mechanical characterization of steel for fastening in a wide range of strain rate
- In this paper, the preliminary results of the mechanical characterization in a wide range of
strain rate of the 30MnB4 steel, usually adopted for fasteners, are described. In this study the
different issues required to implement the dynamic test results in numerical code have been
analyzed. Different experimental techniques have been used for different strain rates: universal machine, Hydro-Pneumatic Machine, JRC-Modified Hopkinson Bar and Split Hopkinson
Pressure Bar. The failure at high strain rate has been examined by means of fast digital image
recording systems. The material shows enhanced mechanical properties increasing the strain
rate: this fact can be taken into consideration to improve the product design and the manufacturing process. The experimental research has been developed in the DynaMat laboratory
of the University of Applied Sciences of Southern Switzerland and in the Laboratory of Dynamic Investigation of Materials in Nizhny Novgorod, in the frame of the Swiss - Russian Joint
Research Program.
Contents
- P. Szeptyński:
Some remarks on Burzyński's failure criterion for anisotropic materials
- Some misstatements appearing in the final form of the failure criterion formulation, derived from Burzyński's hypothesis of material effort for anisotropic bodies, which haven't been
noticed in the literature as yet, are pointed out and discussed. Alternative interpretations of
the results obtained by Burzyński are presented. Propositions of different formulation of the
failure criterion, basing on original ideas of Burzyński, are given.
Contents
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