Asymmetry Thermal Analyses of Self-Supporting Friction Stir Welding

Due to the inherent issue of requiring rigid back support, friction stir welding (FSW) has serious limitations for the welding of hollow structures. Self-supporting friction stir welding was proposed to join hollow aluminum extrusions, which could reduce the hindrance of the welding tool and the requirement of rigid back support. In this paper, finite element modeling analyses were carried out for the asymmetric temperature field in the process of self-supporting FSW. The peak temperature of the stir zone appeared in the upper shoulder affected zone, followed by the lower shoulder affected zone. In the upper shoulder affected zone, a peak temperature was not shown at the center of the curve due to the positive correlation between heat generation and radius and different heat dissipation rates. Considering the influence of thermal input and rotation speed on joint formation, 200 mm/min travel speed and 800 rpm rotation speed are the most proper parameters for 5-mm-thick 6082-T6 aluminum alloy self-supporting FSW butt welds.

Sustainable Analysis of Process Parameters during MIG Welding of 1018 Mild Steel

The present work analyses MIG in terms of strength and consumption of energy during joining of similar AISI 1018 Mild Steel plates. Sustainable manufacturing is the creation of various manufactured products that generally use different processes that will minimize negative impact on environment, conserve natural resources and energy, are also safe for the employees, consumers and communities as well as economically sound. Sustainable manufacturing highlights on the necessity of an energy effective process that optimize consumption of energy. AISI 1018 mild steel is extensively used in automotive industries for pins, worms, dowels gears, non-critical tool components etc. Main important output responses are Tensile Strength and energy consumption during MIG Welding Process by taking Current, Travel Speed and Voltage as effective input variables. The main objective is to optimize energy consumption as well as tensile strength also determination of main influential process parameters on energy Consumption and tensile strength by using Taguchi Method. Contour plot has been also shown.

Investigation of Control Method for Connected-Automated Vehicle to Multiplex Dedicated Bus Lane

Dedicated bus lanes (DBLs) have been widely utilized to ensure public transport priority. To improve overall road efficiency, various control methods of multiplexing DBL are developed and discussed. In this study, we focus on the control method which is based on the connected-automated vehicle (CAV) technology, and the proposed method is validated by using microscopic traffic simulation. The simulation results show that two proposed control methods of multiplexing DBL can reduce the average delay and the average number of stops and increase the travel speed. In comparison, the real-time control method based on the CAV technology offers better effects than the improved signal light control method.

Effect of brass interlayer on microstructure, mechanical and corrosion behaviour of friction stir welded AA6061-T6 alloy

In this study, friction stir welding (FSW) was performed on AA6061-T6 with and without brass interlayer. The FSW with interlayer was performed for various tool rotational speeds (600–1000 r/min) and at constant travel speed (25 mm/min). The defect-free joint with uniform distribution of brass particles in the stir zone (SZ) and formation of the uniform composite structure was observed at an intermediate optimized tool rotational speed of 800 r/min due to the proper material flow. A strong metallurgical bond between brass particles with aluminium alloy resulted in the formation of Al2Cu and Al4Cu9 strengthening intermetallic compounds (IMCs). The average grain size obtained for the weld with interlayer is smaller than weld without interlayer. The presence of the interlayer enhanced the hardness and the tensile strength compared to the weld without interlayer. This improvement in mechanical properties with interlayer is attributed to the formation and uniform distribution of strengthening IMCs. The corrosion analysis was carried out in 3.5% NaCl solution using immersion test and electrochemical polarization test. The weld with interlayer showed enhanced corrosion resistance than the weld without interlayer which is attributed to the formation of major Al2Cu IMC which has less activation energy for the corrosion process.

The Impact of Rolling Stock Heterogeneity on Tram Stop Dwell Time

The prediction of stop dwell time is a major issue in travel speed modeling, i.e., in the definition of travel time for high-frequency and high-ridership rail public transport. This is due to the numerous influential factors associated with stop dwell time, variable both in space and time, such as passenger flow, vehicle and stop design characteristics, and traffic organization. To investigate the impact of the heterogeneity of tram vehicles on stop dwell time, a survey was conducted regarding the tram network of the City of Zagreb. The dwell time at three consecutive island stops served by three different tram vehicle types was analyzed. The stops are located near the city center, in a separate tram corridor, at the far side of signalized intersections. Dwell time was determined and evaluated through the statistical analysis of observed, measured, and video-recorded data. The results show that at stops with up to 200 passengers per hour, the dwell time is around 15 s. For volumes of 20 passengers or less per tram, the dwell time is mostly affected by the tram door opening mechanism and opening/closing time. As the passenger volumes become higher, the number of doors per vehicle becomes more significant.

Measuring regional accessibility with public transport – case of Koroška region, Slovenia

Public transport plays a major role in sustainable mobility planning. This is even more obvious on regional level, where distances are often too long for cycling, therefore public transport remains only viable sustainable travel mode. In the process of preparation of regional SUMP, evaluation of accessibility is one of crucial steps. However, accessibility measurement can be a challenging task. In Slovenia, there have been several studies measuring frequency and access to closest stop, ignoring travel speed and destinations that could be reached. However rapid increase in computing power, software development and availability of schedule data in GTFS format, opened an opportunity to evaluate accessibility more precisely. We performed an analysis for Koroška region in Slovenia. Accessibility was measured with OpenTripPlanner with OpenStreetMap data for road network and schedules in GTFS format. Travel times were measured in both directions for all inhabited cells in a grid resolution of one hectare and central settlements of intermunicipal importance. The results of the analysis are important in terms of understanding how many citizens can access settlements of intermunicipal importance with public transport. This will serve as a baseline measure in regional SUMP preparation and will enable future iterations and comparisons. It also enables us to see the gaps in public transport supply and propose improvements. Open-source tools and open data enables this method to be used in other regions as well.

Measuring regional accessibility with public transport – case of Koroška region, Slovenia

Public transport plays a major role in sustainable mobility planning. This is even more obvious on regional level, where distances are often too long for cycling, therefore public transport remains only viable sustainable travel mode. In the process of preparation of regional SUMP, evaluation of accessibility is one of crucial steps. However, accessibility measurement can be a challenging task. In Slovenia, there have been several studies measuring frequency and access to closest stop, ignoring travel speed and destinations that could be reached. However rapid increase in computing power, software development and availability of schedule data in GTFS format, opened an opportunity to evaluate accessibility more precisely. We performed an analysis for Koroška region in Slovenia. Accessibility was measured with OpenTripPlanner with OpenStreetMap data for road network and schedules in GTFS format. Travel times were measured in both directions for all inhabited cells in a grid resolution of one hectare and central settlements of intermunicipal importance. The results of the analysis are important in terms of understanding how many citizens can access settlements of intermunicipal importance with public transport. This will serve as a baseline measure in regional SUMP preparation and will enable future iterations and comparisons. It also enables us to see the gaps in public transport supply and propose improvements. Open-source tools and open data enables this method to be used in other regions as well.

Optimizing The Functional Performance of Road Network using Vulnerability Assessment to Cope with Unforeseen Road Incidents

An Urban Road network is often used for multipurpose trips, due to their transportation functions, such as attractiveness and orientation, as well as social, ecological, and economic features. In Indonesia, road incidents have reportedly increased during the last decade because of a higher frequency of natural hazards, accidents, and on-street mass demonstrations. These incidents are found to degrade or terminate road access, forcing users to utilize alternative routes and decreasing the service performance in adjacent directions. Due to the unexpected occurrences at any location and time, there is a need to investigate the impact of random incidents on road performances. Several accessibility indexes have also been used to evaluate the vulnerability of road networks. However, this is less practical in Indonesia, with the road authority using functional performances as the indicator. This indicates the need for an index to be developed based on road performance parameters. Therefore, this study aims to develop a road performance-based vulnerability index known as the RCI (Road Criticality Index). Combined with a traffic simulation tool, this system is used as an alternative index to assess vulnerabilities, by identifying the road(s) providing worse consequences due to unforeseen incidents. This simulation was conducted by using the PTV Visum, assuming a road section is closed due to the worst incident scenarios. The result showed that the RCI offered a more comprehensive assessment than the existing indicator (volume capacity ratio). The RCI included travel speed and mobility components for evaluating both local and global road performances. With the knowledge of the most vulnerable locations and their consequences, road authorities can prioritize maintenance and development strategies based on the criticality index. Also, preventive measures should be conducted to mitigate risk under a constrained budget. This methodology can be applied to sustainably enhance the resilience of urban road networks.

X-ray CT Analysis of the Cross-Section of a 3D-Printed Deformed Layer

In this study, we experimentally analyzed the deformation shape of stacked layers developed using three-dimensional (3D) printing technology. The nozzle traveling speed was changed to 80, 90, 100, and 110 mm/s when printing the layers to analyze its effect on layer deformation. Furthermore, the cross-sectional area and the number of layers were analyzed by printing five layers with overall dimensions of 1000 (w) × 2200 (l) × 50 (h) mm (each layer was 10 mm high) using Vernier calipers. Moreover, we analyzed the interface and cross-sectional area of layers that are difficult to confirm visually using X-ray computed tomography (X-ray CT) analysis. As a result of measuring the deformation at the center of the layer, it was confirmed that the deformation was greater for lower nozzle traveling speeds. Consequently, the X-ray CT analysis verified that the layer had the same cross-sectional area irrespective of the layer printing order at the same nozzle travel speed, even if the layer was deformed.