Procedia Engineering最新文献

The assessment of service life of composite thermo-structural parts is a primary issue for the aeronautic industry. To this end, a unified damage model for woven composites undergoing both static and fatigue loadings is presented here. Its specificity resides in its rate damage evolution law, which enables to predict the behaviour of the material under cyclic or random fatigue loadings.

Local government have a pivotal role in city planning. However, meeting the conflicting priorities such as plan for urbanization, promote economic prosperity, ensure environmental sustainability besides creating safe, vibrant and liveable places, create major challenges for local administration. While rapid urbanization continue to displace people from their local places, the frequency of disaster events at the local scale and increasing disaster risks place unique challenges on people and their places. This emphasises the need for local government to understand the local places and invest in planning for cities that improve resilience and enhance human connectivity to their places. Meeting these multidimensional needs in local spaces require embedding local and scientific knowledge, past experiences and community expectation to plan and design cities that also deliver multiple social outcomes. Both place-based approach to city planning and creating disaster resilient cities have gathered momentum, however, they continue to occur in isolation. Maximizing these multiple social, environmental and economic outcomes, emphasize the need to align both resilience principles for sustainable urbanization and place based approach planning concepts to plan for places for people. Drawing from these principles and organizational change theory, a conceptual framework is proposed that provide a new lens for local government to plan for place based resilient cities. This place based approach for resilient cities framework incorporates the thinking for change as a dynamic process across the time scales and by understanding the relationship between people and their place. The model proposed is in an Australian context, yet has significant implication for communities at all levels when planning for places for people.

Carbon dioxide, a byproduct of fossil-fuel combustion, is a greenhouse gas, which traps solar radiation in the atmosphere. This cause climate change and global warming issues. Biodiesel has gained increasing attention as an alternative to fossil fuels for reducing the greenhouse gas emissions from the transportation sector. Yellow oleander (Thevetia peruviana) grows extensively in gardens as a decorative tree throughout Sri Lanka. The plant is a potential source of feed stock for biodiesel production as it produces fruit with two seeds with higher oil content as 49.6% (db) and it is a non-utilized oil crop without any economic value. The objective of this study is to produce biodiesel by transesterifying using extracting oil and to determine its properties. Yellow oleander oil with proper free fatty acid limit was pretreated with NaOH as catalyst and anhydrous methanol amount as 20% of oil volume. The produced yellow oleander methyl ester was characterized. It was observed as gross calorific value as 37.74 MJ/kg (ASTM D 240), flash point of 118°C (ASTM D 93), Kinematic viscosity at 40°C of 5.96 mm2/s (ISO 3105:1976), specific gravity of 0.8874 (ASTM D 1298) and density at 15°C of 887 kg/m3. All the tested parameters are within the accepted limits of the biodiesel thus making it an alternate fuel as transportation fuel for diesel engines.

This paper is to investigate the smoke flow temperature beneath the ceiling in an atrium-style subway station. Numerical simulations were carried out in a full-scale model to study the temperature profile beneath the ceiling by considering different fire source locations. Results show that the maximum smoke temperature beneath the ceiling can be predicted using the three models developed by Alpert, Heskestad and McCaffrey. The choice of the most suitable model depends on the fire source location. For the longitudinal temperature distribution along the ceiling, if the disturbance region is far away from the fire source, the temperature profile can be well correlated by the Li’s model. However, if the disturbance region is close to the fire source, the models proposed by Li and He should be used together. The temperature profile beneath the ceiling in this kind of subway station with different fire source locations can be obtained by the combination of these models.

The importance of private sector engagement on risk reduction is increasingly mentioned over the last years. The Sendai Framework for Disaster Risk Reduction 2015-2030 stresses that the private sector should be a crucial partner in achieving disaster resilience. However, the contribution by the private sector is still rare and mostly undertaken by large multinational firms with just a few positive impacts on the local level.

Particularly manufacturing firms are heavily exposed to floods in Indonesia; Jakarta and Semarang are prominent examples. Broader flood risk reduction measures are still insufficiently developed. Therefore, it is argued that firms can reduce the flood risk through collective adaptation measures. We understand collective adaptation as collaborative activities to reduce risks that firms are either initiating or participating together with other firms, the community, NGOs and authorities.

Our own research has revealed that particularly small and medium-sized enterprises (SMEs) rarely engage in collective flood adaptation. Based on our findings, this paper examines which circumstances determine the willingness of SMEs to contribute to flood risk reduction. Instruments in order to increase the willingness to collective adaptation are also discussed.

Scenario-based experiments with 120 SMEs have been conducted in Jakarta and Semarang. These scenarios contain different risk reduction measures (polder system, river expansion and sensitization program), each with different actors’ constellation of contribution. Comparative logistic regressions have been applied to determine context-specific factors, e.g. risk behavior, firm-specific characteristics or level of flood-proneness that influence the willingness to contribute to flood risk reduction.

Overall, the paper provides deeper insights in understanding firms’ engagement in flood risk reduction and gives answers of how firms can be motivated to become an active player on building resilience.

In the automotive light-duty passenger vehicles, double dry clutch provides high comfort and fuel efficiency to passengers with automated gear box. Its functional performance and quality depends on its diaphragm spring. Fatigue analysis on this component and correlation is quite complex because of several manufacturing processes involved like stamping, heat stabilization and shot-peening. The procedure to predict the diaphragm fatigue strength is described in the paper; also it integrates the new simulation softwares capabilities to handle the process effects for evaluation of diaphragm.

This paper outlines the different simulation stages involved to access the fatigue assessment on diaphragm spring; also it is done at various life situations of vehicle: normal, parking, overloading conditions. A great attention is paid for correlation through measurement fitting in simulation.

Between each manufacturing process simulation, the deformed shape and its residual stress-strain data are mapped using customized scripts. After the process simulations, fatigue actuation on diaphragm is done for new, semi-worn and worn positions of clutch. Miner’s damage and its summation are done at each critical point in diaphragm to determine its total life under nominal design.

The Tooth Flank Fracture, TFF, is a failure mode observed in the surface-hardened of gear tooth flanks. There is a fatigue phenomenon which initiates from a subsurface crack that occurs in the transition zone between the hardened layer and the core structure of the tooth. It is substantially initiated close to the mid-height of the tooth in the single pair of contact area from a crack that progresses in a direction normal to the active surface flanks and also spreads in the thickness of the tooth up to the breakage of the non-active flank, slightly above the root fillet.

The two main modes of fatigue damages for gears are: (i) contact fatigue and (ii) tooth bending root fatigue, are well established and addressed in the international standards such as ISO 6336 part 2 and 3. However, up to now, there is no detailed calculation method to determine the load capacity related to the Tooth Flank Fracture, TFF.

The main objective of this work is to develop an efficient and a standardized methodology to identify the occurrence risk of the Tooth Flank Fracture (TFF) in cylindrical gears. Then, to estimate the risk of appearance of TFF, we have studied two fatigue criteria which are introduced in a developed numerical model. The developed approach, which is based on the Hertz theory with the half-space approach, has been validated by finite elements simulations, revealing a good compliance of the “simplified” criteria proposed initially by Dang Van to characterize this failure mode. Good agreement of this criterion is also observed after a comparative study relative to some experimental tests carried out in literature. An advanced parametric study is carried out to properly identify the real impact of the case hardening depth on this damage mode.

Due to the existence of the converging intersections and diverging intersections, the urban underground road of multi-point entry and exit can show complicated forms in the air flow rate and smoke movement in a comparison with the underground road with single-point entry and exit. In this paper, the strategies of original ventilating and exhausting smoke of a certain urban underground of multi-point entry and exit road were simulated and evaluated by using ventilation simulation software IDA RTV. The partial ventilation scheme where the number of fans was reduced was analyzed. The running strategy of fans in the tunnel under three conditions was determined. And the influence of the fans in ramp tunnel on the wind speed of main road was studied. Results indicate that when exhausting smoke in branch section, The mode of operation where jet fan in the section is fully operated is unreasonable, which would lead to excessive wind speed downstream of the shaft. The running of the ramp fan has a certain influence on the wind speed of the main tunnel. In the ventilation and smoke control design, the ramp position and the operating mode of the ramp fan should be fully considered. Operating fans downstream of the shaft reversely can exhaust smoke more effectively. The results provide the theoretical basis for the ventilation and exhaust design of other complicated underground roads.