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It is experimentally known that the surface color of bearing balls gradually becomes brown during long term operation of the bearings under appropriate lubrication conditions. That exhibits the possibility of an estimation method for residual life of ball bearings without any abnormal wear on the surfaces by precise color measurements. Therefore, we examined what set colors on bearing balls by surface observation using scanning electron microscopy and subsurface analysis using transmission electron microscopy. Results showed that an amorphous carbon layer had gradually covered ball surfaces during operation of the bearings. The layer not only changed ball color but also made overall ball shapes closer to a complete sphere. The report also introduces a uniquely developed color analyzer which enabled color measurements on metallic surfaces, such as the above-mentioned balls.

The life of a wheel bearing unit under real load conditions can now be calculated based on actual load histories. These load histories are recorded over many small but discrete time slices where the speed and loads within each time slice can be regarded as constant. This enables the equivalent load Peqv for each time slice to be evaluated by means of the classical bearing life theory of Lundberg and Palmgren. The relative damage contributed by each time slice is then obtained, and eventually, the overall probabilistic damage from the load histories can be established by accumulating the damage derived from each individual time slice. From the damage distribution, the resultant equivalent load PEQV, representing one/several sets of road recordings, can be evaluated using the Palmgren-Miner rule. This resultant equivalent load is then used to evaluate the bearing life by re-employing the bearing life theory of Lundberg and Palmgren.

Nowadays, bearings for motorcycle engines are required to be compact and light weight and have a considerably high performance. In order to meet these requirements, two measures were developed, that is High Refining Steel (HRS) and Special Heat Treatment (SH Treatment). In this paper described are the characteristics of HRS and SH Treatment and the results of investigation on them. The investigation results show that bearings of HRS and bearings with SH Treatment have more than twice longer life than standard bearings, particularly the bearings with SH Treatment have longer life even under lubricating conditions with a low viscous lubricating oil or with a contaminated lubricating oil. As a matter of fact, the bearings of HRS and the bearings with SH Treatment are used for the motorcycle engines and show excellent performances.

Stainless steel grades are now widely used for automotive exhaust systems, driven by the need to increase their durability and to reduce their weight. Exhaust Manifolds are subjected to more severe conditions and peak gas temperatures of 1000°C could be reached in new downsized gasoline engines. Also, longer guaranties are now required. This evolution is a direct consequence of the effort to decrease automotive pollutant emissions with new environmental regulations throughout the world. The paper will deal with the thermal-mechanical fatigue (TMF) damage prediction of fabricated automotive exhaust manifold fixed to the engine. A dedicated lifespan prediction approach was created based on elasto-viscoplastic behavior and damage models identification from different thermal-mechanical tests.

In this paper, a CAE (Computer-Aided Engineering) methodology to simulate the vibration test and predict fatigue life of head lamp bulb shield is presented. A modal analysis is performed first to determine the critical elements from the strain energy density distribution patterns. A random vibration frequency response analysis is then performed to monitor the stress response power spectral densities (PSDs) for critical elements due to the g-load input PSDs, measured at the mounting point in all three directions. Fatigue life can be estimated based on the stress response PSDs and material S-N curve by using Dirlik's method. The fundamentals for frequency domain fatigue analysis are reviewed and a case study with test correlation is then presented.

In the present paper a degradation assessment and life prediction method has been proposed for electro-hydraulic shift valve applied to control wet shift clutch in Power-shift steering transmission (PSST). Unlike traditional analysis of contaminant sensitivity, our work is motivated by the failure mechanisms of abrasive wear with a mathematic model. Plowing process included in abrasion will consecutively increase the roughness of mating surfaces and thereby enlarge the clearance space for leaking more fluid. It is an overwhelming wear mechanism in the degradation of shift valve within serious-contaminated fluid. Herein a mathematic model for assessment and prediction is proposed by considering particle morphology and abrasion theory. Such model has been verified for its applicability and accuracy through comparison between theoretical and experimental results. Assuming the proposed model to be general, valve wearing behavior in any hydraulic system can be simulated.

Refuse Trucks are used to pick up garbage from houses. These trucks have huge robotic arms connected to the frame which are operated by hydraulic mechanism operated by the driver sitting inside the cab of the truck. The operator of the truck controls the robotic arm using a lever. Once the truck is positioned aside the garbage can, the operator moves the robotic arm outwards, grabs hold of the garbage can, picks up the garbage can and dumps the garbage into the truck. During this operation, the frame articulates and moves due to the frame suspension causing the cab to move along with the frame. This operation is performed about 1000 times a day, 5days a week for 12 years which could result in some amount of damage to the cab over its life. Since the time rate of application of the forces during the Automatic Side Loading operation is small compared to the lowest flexible mode of the cab, modal amplification is considered unlikely.

Of the possible Life Support Systems evaluation criteria, the criterion of "integral reliability" is proposed. This criterion incorporates three main indices: reliability, mass, and quality of life. It is possible to interrelate these indices only if the space mission is considered as a whole. It is shown that there must exist a LSS mass optimum with respect to mission reliability. The specific form of "integral reliability" expression and the number of terms depend on the mission scenario. This work considers different LSS for orbital station, Lunar base, and Mars mission scenarios.

In this paper we consider sample size selection for life tests when the product life follows the two parameter Weibull distribution. Two situations are considered: 1) an acceptance test where the purpose is to determine whether the product under test meets specified or historical life objectives and 2) a routine endurance test where the purpose is to determine a parameter’s value within a sufficiently small interval of uncertainty just to add to a growing body of knowledge and serve as an item of information in future as yet unformulated decision making processes.

The lead-acid couple is potentially capable of fulfilling the battery requirement for high performance electric delivery vehicles in the one tonne payload category. Development of such a battery, combining high energy density and good cycle life, involves extensive and painstaking testing. During the course of the Lucas development programme test methods and procedures have been evolved to ensure that the battery array with its supporting equipment is capable of fully performing the tasks required of it in such an application. Much of the experience gained is applicable to any electrochemical couple being developed for electric vehicle use.

One of the key selling criteria of brake linings is their related cost per life time. Individual wear rates must match a required service interval which in most cases is part of the warranty a vehicle is sold with. OEMs, brake manufacturers as well as friction material suppliers are therefore conducting in-depth investigations on the wear behaviour of brake systems and their friction pair. These consider various parameters influencing pad and rotor life expectancy as part of the pre selection process before running final fleet trials for confirmation. Thus, selecting the right test procedures and parameters for the determination of wear rates is key in enabling a confident life time prediction. As of today, a multitude of wear test procedures are used in the automotive industry, each of them related to the specific experience of the respective OEM or BM.

The knowledge of mechanical behaviour of material is vital for durability prediction and attending initial project requirements. Through the experimental evaluations is possible to measure this behaviour and use it as input in numerical simulations. Temperature changes considerably static and dynamic mechanical properties of materials, particularly in elastomers. This study was motivated to predict the durability under several working temperatures of center bearings rubber cushion of driveshafts that needs to achieve prespecified stiffness and durability parameters. Standardized specimens were tested in fatigue for experimental investigation of the rubber compound. Durability tests were performed in the final product sample and compared with tests performed in standardized specimens. It was concluded that this approach produces accurate results for fatigue predictions and provided useful equations for practical design applications and reducing product validation time.

Theoretical estimates are made of life time of Ceramic Turbocharger Rotor (CTR) for suitable mechanical design and suitable material selection. Life time of CTR is predicted taking into account the stress-temperature distribution in CTR, required failure probability, volume effect of strength and material properties. Three fatigue failure modes which are slow crack growth, oxidation, and creep failure are considered. The stress-temperature distribution in CTR in operation is estimated by means of Finite Element Method numerical analysis. The probabilistic design map is proposed as a function of turbine inlet temperature and tip speed.

The survival of humanity in the upcoming decades will depend on the sustainability of the consumed products. There is a global effort to develop solutions to reduce environmental and energy impacts with the production of these products. This paper presents a careful analysis of automotive recycling and the role of aluminum in the life cycle of these vehicles. It is known that the number of vehicles is getting close to 1 billion units while the number of end-of-life vehicles (ELVs) has also been increasing dramatically throughout the entire planet. The average car has between 30 to 150 kg of aluminum, there is an increasing trend in this amount in exchange of a reduced final weight of the vehicle. Aluminum can be recycled repeatedly without losing its physical-chemical properties. There are two ways of obtaining the metal; one is by the direct extraction of natural resources through the mining of bauxite and the second through its recycling.

The objective of this study is to develop a design decision support tool that incorporates life cycle costing including the environmental effects of a system. A life cycle costing that incorporates the effects of the environment is essential to support the design decisions required during today''s product or system developments. Since the international environmental standards (ISO 14000 Series) were issued in the early 1990s, the leading companies in the automotive industry have been developing integrated assessment methodologies. These methodologies attempt to integrate cost, quality, environment and other related areas into the total life cycle assessment of a system. Therefore, it is important to develop a tool that integrates all information concerning the product in the early stages of development. It is also appropriate to support the decision-making in selecting the best design alternatives.

In the vein of the paper we presented at the last SAE Congress (SAE 970538), the evolution of the exothermic process of combustion (an event referred to popularly as ‘heat release’) in an engine is considered from the point of view of the utilization of fuel. Its consumption in the course of this process is expressed in a functional form, akin to that engendered for mathematical description of life. There are a number of such functions recorded in the literature and their salient features are revealed. Of particular relevance to fuel utilization in engines is a reverse form of the Vibe function (known in the English engine literature as the ‘Wiebe function’), which we call the fuel life function. Its parameters can be derived from numerical modeling of combustion in engines or from reduction of indicator diagram data.

This study is a life-cycle assessment (LCA) comparing two types of a powertrain structural component: one made of diecast primary aluminum and another hypothetical part made of semi-solid injection molded primary magnesium (Thixomolded®). The LCA provides an indication of the potential environmental burdens throughout the life-cycles of both parts, ranging from raw material acquisition to product end-of-life. Preliminary results show high sensitivity to selection of primary vs. secondary metals, and to the SF6 emission factor used in the model. Opportunities exist for reducing energy consumption using secondary instead of primary metals for both parts, although the use of such is influenced by market supply and demand

Life-cycle cost analysis can provide a solid basis to support improvements in how fleet managers use their vehicles and in how manufactures design them. The challenge to it be an established practice rests on getting quality data provided by fleet operators and on the understanding that the data is significantly influenced by both the operational environment and the quality of management (operations and maintenance). In 2012, a benchmark study was conducted using the public transportation system of Salvador, Bahia, Brazil. Twelve companies participated in the study. Although the primary purpose of the study was to assess the differences in the competitiveness among the twelve companies, the data collected provide a database that was very consistent in providing critical analysis of vehicle maintainability by generating life-cycle cost analysis. The study proved to be an important tool to link vehicle design to the operational and maintenance management of company fleets.

A detailed component performance, ratings, and cost study was conducted on series and parallel hybrid electric vehicle (HEV) configurations for several battery pack and main electric traction motor voltages while meeting stringent Partnership for a New Generation of Vehicles (PNGV) power delivery requirements. A computer simulation calculated maximum current and voltage for each component as well as power and fuel consumption. These values defined the peak power ratings for each HEV drive system's electric components: batteries, battery cables, boost converter, generator, rectifier, motor, and inverter. To identify a superior configuration or voltage level, life cycle costs were calculated based on the components required to execute simulated drive schedules. These life cycle costs include the initial manufacturing cost of components, fuel cost, and battery replacement cost over the vehicle life.

One of the most promising battery types under development for use in both pure electric and hybrid electric vehicles is lithium ion. These batteries are well on their way to meeting the challenging technical goals that have been set for vehicle batteries. However, they are still far from being able to meet the cost goals. The Center for Transportation Research at Argonne National Laboratory (Argonne) undertook a project for the United States Department of Energy (USDOE) to estimate costs of lithium ion batteries and to project how these costs might change over time, with the aid of research and development. Cost reductions could be expected as the result of material substitution, economies of scale in production, design improvements, or development of new supplies.