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Concrete subjected to high strain rates behaves notably differently in comparison to quasi-static conditions, which can be affected by the addition of steel fibers. The influence of steel fibers on the dynamic compressive behavior of self-compacting concrete (SCC) was studied experimentally using Split Hopkinson Pressure Bar (SHPB) tests. The investigations were performed in a range of quasi-static rates up to dynamic strain rates of 462 1/s. The effect of steel fibers on the stress-strain diagram, dynamic increase factor (DIF) and failure pattern of SCC conducted under high strain rates was analyzed. The experimental results presented in this paper and the ones from recent works of other authors indicate that application of steel fibers reduces the strain-rate sensitivity of different concretes and has a beneficial effect on the specimen failure pattern. Moreover, the conducted SHPB tests show an important role of fibers in reduction of the strain rates reached in the specimen under the same pressure level in comparison to plain concrete specimens.

The article provides a discussion on the studies comprising active experiments conducted on passenger car and analytical experiment on application of neural networks in the identification of pressure level in tires of a vehicle based on vibration signals. The purpose of research was to analyze the possibilities of monitoring of pressure in tires during the diagnostics tests of shock absorbers. The paper presented on last International Congress on Technical Diagnostics in 2008 examined the influence of changes of pressure in tires on the results of diagnostics test of shock absorbers. Those influences were observed in typical test methods used in vehicles service stations and even in new vibration methods. The article presents some results of research on neural network classification method of pressure in tires level. Tested solutions can be used as the preliminary module of diagnostics system during the shock absorber test. The signal processing methods were based on application of time, frequency and time-frequency transformations which enables obtaining the signals information carried in one or two domains simultaneously, namely those of time and frequency.

Recently, composite materials are used in many fields because their properties are high strength, high stiffness, and they have light weight, good corrosion resistance and good thermal conductivity. However, composite materials have relatively a lot of problems, especially delamination, compared with common materials such as a steel and aluminum, etc. Therefore, having the interlaminar fracture toughness for a laminate composite is important. In this study, the end notched flexure (ENF) specimens are employed in order to evaluate modeⅡ interlaminar fracture toughness for CFRP laminate composites. Three kinds of a/L ratio were applied to these specimens under the different pressure level. Also, we discuss the relation of crack growth and the interlaminar fracture toughness in terms of AE characteristics using ENF test.

In this paper, non-linear interactions between a stent and an artery are analyzed using the finite element method [ANSYS (Ver 10.0)]. The material property of the artery is assumed to be hyper-elastic. The loading conditions were applied in three steps, according to the pressure level (pressure increase, constant load pressure, and pressure decrease). From the results, the maximum von Mises stresses were measured in the area of contact of the stent and the artery. The maximum von Mises stresses of the stent and artery were obtained and the increase in the maximum pressure showed a decrease in the von Mises stress of the stent. The simulated results show that the distal end of the stent, which tilted after the expansion behavior in the artery, may damage the artery wall. The finite element model used in this study may help in designing the stent.