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In the present study, the effect of an La alloying element with different quantities (1, 3 and 5 wt.-%) on the microstructure, mechanical and dry sliding wear properties of Mg- 3Al-3Sn-3Sb alloy was investigated. The wear tests were done on the alloys using pin on-disk equipment against a 4140 steel disc as counterpart under three different sliding velocities of 0.3, 0.6 and 1.2 ms-1 and four different loads of 5, 10, 20 and 40 N. The microstructural results showed that the new intermetallic phases (La5Sn3 and LaSnSb2) were formed with addition of La to the main alloy. Also, it was observed that the hardness of the Mg-3Al-3Sn-3Sb alloy was raised with increasing La addition. Furthermore, the tensile properties of the Mg-3Al-3Sn-3Sb alloy improved with rising La content at room and elevated temperature. The wear rates of the alloys increase with increasing of the sliding speed and load. In addition to this, the wear rate of the Mg-3Al-3Sn-3Sb alloy was found to be higher than that of the La content alloys for all test conditions.

This article presents an implementation of one of the latest optimization methods of obtaining light vehicle designs. First, the problem of coupling with a bolted rim is optimized using the butterfly optimization algorithm (BOA). Finally, the BOA is used to solve the shape optimization of a vehicle suspension arm. It is utilized from the Kriging metamodeling method to obtain equations of objective and constraint functions in shape optimization. At the end of the research effort in this paper, the weight reduction of the suspension arm by using the BOA is 32.9%. The results show the BOA's ability to design better optimum components in the automotive industry. King Fahd University of Petroleum and Minerals Khon Kaen University

WOS: 000438680000042, In most decades, the height of structures and the number of basement floors have been increased especially in the valuable sites. By constructing the piles around the construction for safety purposes, a pool environment is occurred. Water accumulation in the excavation site due to various reasons might cause basement floors, forming a closed volume, to move upwards. This very risk is also prevalent for all the structural elements below soil in flood susceptible areas. This problem, which arises when necessary precautions are not taken, is generally overlooked by the engineer while aiming for the completed structure weight. Floating damage is completely different from the liquefaction of soil, which results from unexpected movements in a structure due to the loss of the bearing capacity of the soil. Unfortunately, this underestimated hazard is indicated in the standards and codes only for port structures in coastal areas. In this study, it is aimed to point out that the structural damage due to the buoyancy force can be avoided by paying attention to basic mechanical concepts and design procedures That's why, an office building in Hatay/Turkey which was damaged during construction as a result of the buoyancy force occurred in a flood has been chosen and examined as a case study.

Reliability-based design optimization (RBDO) is an effective method for structural optimization due to its ability to take into consideration uncertainties in design variables. Performance measure approach (PMA) based methods are commonly utilized to evaluate the probabilistic constraints of RBDO problems. The advanced mean value (AMY) method is a very commonly used due to its simpleness and effectiveness. However, the AMV method sometimes produces unstable and inefficient results for concave and highly nonlinear limit-state functions. In order to improve robustness and efficiency, many methods have been developed, for example, chaos control based and conjugate gradient-based methods. These methods lead to more stable results as compared with the AMV approach but they are inefficient for use in complex and convex limit-state functions. The RBDO of structural components is often a difficult issue due to complicated constraints. In this paper, a novel hybrid approach, referred to as "hybrid gradient analysis (HGA)" is introduced for the evaluation of both convex and concave constraint functions in RBDO. The HGA method combines AMV and conjugate gradient analysis (CGA). The robustness, simpleness and effectiveness of the proposed HGA method are compared with various PMA methods aimed at reliability such as AMV, chaos control (CC), conjugate mean value (CMV), modified chaos control (MCC), hybrid mean value (HMV) and CGA methods by means of several nonlinear convex/concave limit-state functions and structural RBDO problems. Reliability analysis and RBDO results point out that the HGA approach introduced here is more effective and robust than the well-known approaches. Ministry of Science, Industry and Technology of Turkey National Science Foundation U.S. Department of Energy Mississippi State University

WOS: 000456719900023, The purpose of this study is to investigate crankcase explosion in two-stroke marine diesel engine systematically by using fault tree analysis method in fuzzy environment for system reliability and shipping sustainability. Maritime accidents might cause deadly and costly results in both human lives, commodities, environmental and financial aspects. Crankcase explosion is one of the most dangerous causalities that might possibly damage both ship structure and crew members. In this study, we determine all root causes of crankcase explosion, and calculate the probabilities in a stepwise manner by implementing field expert consultations. As a result, we find that the occurrence probability of the crankcase explosion is 1.249428E-007 which is close to real case. Bearing originated hot spots and personnel failures are also found as the most risky events.

WOS: 000373167400006, In the Van Earthquake of magnitude Mw = 7.2 on October 23, 2011, 48,666 buildings were severely damaged or collapsed, 604 people lost their lives and 1301 people were injured. During this earthquake, not only the buildings designed in accordance with the old earthquake codes but also the ones designed in accordance with the current Turkish Earthquake Code (TEC) were severely damaged. The purpose of this study is to reveal the reasons why the RC buildings designed in accordance with the current TEC as a result of static and dynamic calculations were severely damaged in the recent earthquakes. In this study, first, the buildings that were designed in accordance with the last two earthquake codes and damaged during the Van Earthquake on 23 October 2011 have been examined. Then, another severely damaged building that was designed in accordance with the TEC 2007 has been chosen as a possible model for similar situations. In order to explore the reasons behind the damage, detailed examination has been made both in the damaged structure and in its design calculations. Both situations in the project and implementation of the design have been analyzed by using IdeCAD and Sta4CAD modeling, as well as Sap2000 through which weak structural members have been determined. The findings have been evaluated in terms of design and implementation flaws, in compliance with the TEC 2007, modeling and acceptance error. When analyzed by modeling of its project, the building has not revealed any insufficient columns; however, in its implementation analysis, the damaged members have appeared to be insufficient. It has been determined that the damage was due to improper implementation of the project, incompatible production according to the TEC 2007 and lack of inspection. To mitigate possible fatalities and damages in the future earthquakes, implementations should be fully represented in the model of the projects, structural members in the projects should be built identically to their design, attention should be paid to the anticipated limitations in TEC 2007 during implementation, and stages of project and implementation should be inspected sufficiently. (C) 2016 Elsevier Ltd. All rights reserved., Mustafa Kemal University, The studies performed in the region after the Van Earthquake have been carried out by M. Cemal Genes from Zirve University, Hakan T. Turker and Selcuk Kacin from Mustafa Kemal University along with Mustafa Kemal University Civil Engineering students Muhammet Sadik Lenk, Bekir Danyildiz, Aytac Guler and Ilker Basaran with the sponsorship of Mustafa Kemal University. Hatay Chamber of Civil Engineers has provided logistic support contacting the Van branch. Civil Engineers Ilhan Gunay and Ferman Toro, who work in Van and Ercis, have supported on-site examinations in the area. Civil Engineers Muzeyyen Balcikanli and Bunyamin Akyol have also helped with the study. Sap2000, IdeCAD and Sta4CAD softwares have given support regarding the licenses. The authors express their sincere thanks to the above-mentioned people, institutions and organizations for the support they have provided.

WOS: 000372851000015, This paper describes the fatigue failure of a rotary dryer in a chemical plant. The process conditions required the dryer to be rotated continuously at a speed of about two and half revolutions per minute. The shell structure of this large drum is formed by combining segmented shell parts using bolted ring flange joints. Because of the gross weight of the dryer in operation time, each joint was subjected to bending moment. In the first two years in service, micro cracks were occurred by fatigue. The failure was analyzed using the fatigue curves given in ASME Boiler and Pressure Vessel Code Section VIII Division 2 and EN 13445 Unfired Pressure Vessels Part 3 Codes. Finally, flange joints were removed from the drum and new cylindrical parts adapted to the drum using butt welding after reaching better results in FEM and fatigue calculation. (C) 2016 Elsevier Ltd. All rights reserved.

WOS: 000451968400003, In this study, the weldability of lower strength St 37 grade steel plate with a higher strength steel plate (i. e., St 44) using the friction stir welding technique has been studied. St 37 grade steel sheets are widely used in various industries. However, the joining of St 37 steel plates with higher strength grades such as St 44 grade steel is usually required when the strength of St 37 grade is not sufficient. Therefore, microstructural and mechanical properties of friction stir welded St 37-St 44 butt joints were investigated by conducting optical microscopy, microhardness measurements, and tensile testing. A fine-grained recrystallized microstructure was observed in the weld regions of the joints produced. The highest tensile strength, i. e. 385 MPa, was exhibited by the joint produced at 630 rev x min(-1).

WOS: 000381839900017, This paper describes the fatigue failure of girth gear manufactured from low alloy cast steel of rotary dryer in a chemical plant. The cracks of T-section web of the girth gear occurred at the end of 25 year working period because of stress intensity factor. Because of normal condition of working surfaces of teeth, spare gear was not thought and repair welding was the only option. Nickel based super alloy electrode was used for repairing and it had been successful until the new gear was ordered. The factors behind the fatigue failure and the reasons of temporary repairment were discussed using the cause-effect diagram. Higher grade bolt using instead of design grade, insufficient stiffener of web, insufficient preparation of repair welding and wide section welding beads at the welding deposits were found as the reasons of changing the girth, gear with the new one. (C) 2016 Elsevier Ltd. All rights reserved.