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Materials science and engineering is one of the hot research topics in the world, among which mechanical properties of materials play a critical role in application of the new materials. Based on this, a special session Mechanical Properties of Materials was held within the 2nd Global Conference on Materials Science and Engineering, Nov. 20-22, 2013. This special issue contains a selection of twenty scientific papers, which are focused on the structure, mechanical properties, and strength of materials. In this review, the selected papers from the special session are summarized. Introduction. The Global Conference on Materials Science and Engineering (CMSE) is an annual event since 2012. The CMSE 2013 was held by Hubei University of Science and Technology in the City of Xianning (Hubei, China), November 20-22, 2013. Within this event, a special session named Mechanical Properties of Materials was held. In this session, 31 papers were selected for publication, of them 20 papers are published in this special issue (1-20), two more (21, 22) in the next issue, and 9 papers are published by Materials Research Innovations (23-31). All papers underwent the standard peer-review process of the journal and were accepted for publication based on the evaluation of at least two independent anonymous reviewers. Highlighted Papers. Results of the study (1) indicate that crack tip stress distribution characteristics and crack propagation dynamics are closely related to the microstructure evolution caused by the change of a strain rate and temperature. At a lower strain rate and temperature, the crack propagated by a brittle mechanism without the change in atomic configuration near the crack tip. The stress concentration occurred at the crack tip of a growing crack. The crack propagation exhibited a gradual brittle-to-ductile transition with increasing temperature and strain rate, the peak stress was accompanied by the appearance of the microstructure evolution ahead of the crack tip. In (3), uniformly distributed TiC nanoparticle-reinforced iron-based composites were successfully prepared by planetary milling in argon and subsequent hot pressing. Nearly full density composite specimens could be obtained via milling for 6 h followed by hot pressing at 1100C under 50 MPa. Comparatively spherical TiC particles and fine fibrous Fe3C phases were observed in the iron matrix composite. Microstructural analysis results show that the average diameter of TiC particles and the length of Fe3C phases tend to decrease with an increase in the TiC volume content. Her and Wu (7) studied the annealing effect on the microstructure and mechanical properties of titanium nitride (TiN) films. Atomic force microscopy analysis demonstrated that surface roughness of TiN films decreased from 3.83 to 2.43 nm as the annealing temperatures increased from 100 to 300C. Atomic force microscopy image of

One of the most important challenges of storing fluids in thin walled pressure vessels under internal pressure is preventing crack propagation. At low temperatures, steel shows brittle crack propagation characteristic, which is highly dangerous. In this paper, a new numerical model is presented, in order to investigate the reinforcement of a cracked thin walled pressure vessel by composite patch. The extended finite element method (XFEM) technique is used to model brittle crack propagation through the thickness of a thin-walled pressure vessel utilizing the multi-scaling technique. Crack propagation in the thickness of a pressure vessel was studied utilizing the combination of XFEM approach in fracture mechanics and multi-scaling technique. Then, the critical energy, which is the maximum strain energy that the pressure vessel can absorb before the brittle crack starts to propagate, was calculated using the numerical techniques of XFEM. In order to increase the critical energy, cohesive elements and composite patches with different stacking sequence, which were extracted from previous experimental and analytical studies, were used, and the best stacking sequence was identified using the current XFEM code. Moreover, the optimization was carried out using the traditional optimization technique for reinforcing with composite patches, which was based on the optimum ratio of the increased critical energy to the thickness of the reinforcement. Results obtained show that, keeping constant the reinforcing thickness and changing the stacking angle, the maximum energy capacity is increased by 7–11%. Also, by increasing the thickness of the reinforcement, a significant growth in strain energy capacity (up to 40%) is observed. The Hashin damage criterion was used to ensure that none of the laminas’ damage during the crack propagation is critical.

For enhancing the flexural strength of existing reinforced concrete beams provision of external bars at the soffit of the beam is identified as one of the cost effective and easy to execute method. This paper discusses the finite element modeling and nonlinear analysis of reinforced concrete beams with additional external reinforcing bars at the soffit level using ANSYS 12.0 software. Finite element modeling of reinforced concrete beams is carried out using discrete reinforcement modeling and the results are compared with experimental results of twenty numbers of beam specimens under four-point bending. SOLID65, SOLID45, and LINK8 elements were used finite element modeling of the beam. COMBIN39 spring elements were used for simulating the frictional contact between the soffit and the external bars. Wide range graphical display of the results such as deflected shape of the beam, strain variation along the length and depth of the beam and crack propagation at various loading stages were generated by creating a batch file using ANSYS parametric design language.

This paper examines the low-cycle fatigue and cracking-resistance characteristics of 12Kh1MF steel by testing specimens and full-size sections of steam lines produced from a single industrial batch of pipes with an external diameter of 194 mm and a wall thickness of 36-39 mm. The steel was also subjected to standard long-term strength tests and its chemical composition and mechanical properties were determined. The results of the investigation satisfied the technical requirements on the supply of steam lines and varied on the level of mean grade values.