Wyniki wyszukiwania - BazTech

1

Mechanical characterization of steel for fastening in a wide range of strain rate

Cadoni E., Bragov A. M., Dotta M., Forni D., Konstantinov A., Lomunov A., Ripamonti A.

Engineering Transactions

|

2011

|

Vol. 59, iss. 2

101-117

EN

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 di?erent issues required to implement the dynamic test results in numerical code have been analyzed. Different experimental techniques have been used for di?erent strain rates: univer- sal machine, Hydro-Pneumatic Machine, JRC-Modi?ed 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 manu- facturing 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 Dy- namic Investigation of Materials in Nizhny Novgorod, in the frame of the Swiss – Russian Joint Research Program.

2

Mechanical response of HPFRCC in tension and compression at high strain rate and high temperature

Cadoni E., Bragov A. M., Caverzan A., Prisco di M., Konstantinov A., Lomunov A.

Engineering Transactions

|

2010

|

Vol. 58, iss. 3/4

139-151

EN

The mechanical response of High Performance Fibre-Reinforced Cementitious Composite (HPFRCC) has been analyzed at high strain rates and high temperature. Two experimental devices have been used for compression and tension tests: the traditional Split Hopkinson Pressure Bar for compression and the JRC-Split Hopkinson Tension Bar for tension. The HPFRCC was thermally damaged at 3 temperatures (200 C, 400 C and 600 C) in order to analyze the dynamic behaviour of this material when explosions and fires took place in a tunnel. Results show that significant peak strength increases both in tension and in compression. The post-peak strength in tension depends on the thermal damage of the material. Its strainrate sensitivity and thermal damage have been illustrated by means of a Dynamic Increase Factor. These results show that it is necessary to implement new expression of the DIF for the HPFRCC, therefore more and more accurate and experimental studies using Kolsky-Hopkinson Bar methods are needful.

3

Liquid sloshing excited by pressure on a sport of a free Surface

Cattani C., Konstantinov A.

Vibrations in Physical Systems

|

2002

|

Vol. 20

208--209