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Abstract Reliability analysis of a large-scale system under random dynamic loads can be a very time-consuming task since it requires repeated studies of the system. In many engineering problems, for example, wave loads on an offshore platform, the excitation loads are defined using a power spectral density (PSD) function. For a given PSD function, one needs to generate many time histories to make sure the excitation load is modeled accurately. Global and local approximation methods are available to predict the system response efficiently. Each way has their advantages and shortcomings. The combined approximations (CA) method is an efficient method, which combines the advantages of local and global approximations. This work demonstrates two methodologies that utilize CA to reduce the cost of crude or separable Monte Carlo simulation (MCS) of linear dynamic systems when the excitation loads are defined using PSD functions.

Road vibrations cause fatigue failures in vehicle components and systems. Therefore, reliable and accurate damage and life assessment is crucial to the durability and reliability performances of vehicles, especially at early design stages. However, durability and reliability assessment is difficult not only because of the unknown underlying damage mechanisms, such as crack initiation and crack growth, but also due to the large uncertainties introduced by many factors during operation. How to effectively and accurately assess the damage status and quantitatively measure the uncertainties in a damage evolution process is an important but still unsolved task in engineering probabilistic analysis. In this paper, a new procedure is developed to assess the durability and reliability performance, and characterize the uncertainties of damage evolution of components under constant amplitude loadings.

Despite numerous research efforts, there is no reliable and widely accepted tool for the prediction of erosion prone material surfaces due to collapse of cavitation bubbles. In the present paper an Erosion Aggressiveness Index (EAI) is proposed, based on the pressure loads which develop on the material surface and the material yield stress. EAI depends on parameters of the liquid quality and includes the fourth power of the maximum bubble radius and the bubble size number density distribution. Both the newly proposed EAI and the Cavitation Aggressiveness Index (CAI), which has been previously proposed by the authors based on the total derivative of pressure at locations of bubble collapse (DP/Dt>0, Dα/Dt<0), are computed for a cavitating flow orifice, for which experimental and numerical results on material erosion have been published. The predicted surface area prone to cavitation damage, as shown by the CAI and EAI indexes, is correlated with the experiments.

The research on the characteristics of vehicle movement is the premise to guarantee the smooth operation of electric vehicles, and it’s also the basis for developing the vehicle ability in depth. Therefore, it’s essential to study on the vehicle movement characteristics. And steering on ramp is a typical working condition for tracked vehicle. Firstly, the kinematics and dynamics of tracked vehicle during the steering process on ramp are analyzed in detail aiming at the problem that it’s complex and difficult to describe the process of steering, and the dynamics model of tracked vehicle is established in the condition of the offset of instantaneous steering center and the sliding of the track and other factors. Second, the relationships between driving force, steering radius and slop are obtained by simulation, and the variation rules of these parameters are analyzed. Finally, the model of steering on ramp is verified using electric tracked vehicle.

Durability and reliability performance is one of the most important concerns of a recently developed Thermal Regeneration Unit for Exhaust (T.R.U.E-Clean®) for exhaust emission control. Like other ground vehicle systems, the T.R.U.E-Clean® system experiences cyclic loadings due to road vibrations leading to fatigue failure over time. Creep and oxidation cause damage at high temperature conditions which further shortens the life of the system and makes fatigue life assessment even more complex. Great efforts have been made to develop the ability to accurately and quickly assess the durability/reliability of the system in the early development stage. However, reliable and validated simplified engineering methods with rigorous mathematical and physical bases are still urgently needed to accurately manage the margin of safety and decrease the cost, whereas iterative testing is expensive and time consuming.

Fatigue, creep, oxidation, or their combinations have long been recognized as the principal failure mechanisms in many high-temperature applications such as exhaust manifolds and thermal regeneration units used in commercial vehicle aftertreatment systems. Depending on the specific materials, loading, and temperature levels, the role of each damage mechanism may change significantly, ranging from independent development to competing and combined creep-fatigue, fatigue-oxidation, creep-fatigue-oxidation. Several multiple failure mechanisms based material damage models have been developed, and products to resist these failure mechanisms have been designed and produced. However, one of the key challenges posed to design engineers is to find a way to accelerate the durability and reliability tests of auto exhaust in component and system levels and to validate the product design within development cycle to satisfy customer and market's requirements.

Abstract Geometric variation stemming from manufacturing can be a limiting factor for the quality and reliability of products. Therefore, manufacturing assessments are increasingly being performed during the early stages of product development. In the aerospace industry, products are complex engineering systems, the development of which require multidisciplinary expertise. In such contexts, there are significant barriers against assessing the effects of geometric variation on the functionality of products. To overcome these barriers, this article introduces a new methodology consisting of a modelling approach linked to a multidisciplinary simulation environment. The modelling approach is based on the parametric point method, which allows point-scanned data to be transferred to parameterised CAD models. In a case study, the methodology is implemented in an industrial setting.

Real-time control systems have continued to advance along with other electronic devices and are now being utilized in the heavy-duty truck industry. These systems are designed to electronically control events as they happen and provide up-to-date diagnostic information, thus increasing the operating efficiency, reliability and safety of the vehicle. Real-time control systems have a potential for many different applications beyond those which are currently being employed in the trucking industry.

Diesel particulate trap systems are one of the effective means for the control of particulate emission from diesel vehicles. Hino has been researching and developing various diesel particulate trap systems for city buses. This paper describes two of the systems. One uses a wall flow filter equipped with an electric heater and a sensing device for particulate loading for the purpose of filter regeneration. Another makes use of a special filter named “Cross Flow Filter” with an epoch-making regeneration method called “Reverse Jet Cleaning”, by which it becomes possible to separate the part for particulate burning from the filter. Both systems roughly have come to satisfy the functions of trap systems for city buses, but their durability and reliability for city buses are not yet sufficient.

The paper will review existing seals used in off-highway heavy equipment, both radial lip seal applications and face type seal applications in general use on track vehicles. With the trend towards improved reliability and durability, together with the never ending quest for quality and product improvements, the paper will discuss a number of seal development programs which will result in products that meet the new and projected future requirements for seals from the off-highway heavy equipment manufacturers.

This is an assessment of Japanese High Speed Surface Transport (HSST) policy, vision, goals, and magnetic levitation development and commercialization strategy. It includes a status report for a test program now underway to demonstrate the safety, reliability and economic viability of the HSST-100 maglev train system. HSST-100 is one of three types of HSST maglev trains planned for implementation in Japan: HSST-100 for 100 km/h urban service, HSST-200 for 200 km/h medium range suburban service, and HSST 300 for the 300 km/h long range interurban application. For the HSST-100 program, included are detailed specifications for the vehicle, location of the Chubu (Central Japan) test site South of Nagoya, test site guideway specifications, guideway switching concept, test site facility description, major test activities, and test event schedule.

The key words in the marketplace for off-highway vehicles are durability, performance, and efficiency. A manufacturer of these vehicles recognizes that one way to successfully address these needs is by a well thought through electronics design. With the computer sophistication now being incorporated into off-highway vehicles, engineers must work closely to assure electromagnetic compatibility (EMC) of the entire system. A properly established EMC program extending from concept to final design will support each of a product's specified operations and still function as an integrated whole. This paper describes the process for designing the EMC for an off-highway vehicle.

It is commonly believed that running-in behavior is related to engine reliability and fuel economy. This paper uses a methodology to find the influence of running-in, based on telematics data. In this paper, the key related telematics parameters are identified to assess running-in behaviors through feature analytics with telematics vehicle real-road data. By analyzing these parameters, truck groups subjected to different running-in behaviors are classified to evaluate the relationship between running-in behaviors and fuel economy.

Abstract Automated vehicles require some level of subsystem redundancy, whether to allow a transition time for driver re-engagement (L3) or continued operation in a faulted state (L4+). Highly automated vehicle developers need to have safe miles accumulated by vehicles to assess system maturity and experience new environments. This article presents a conceptual framework suggesting that hardware newly available to commercial vehicle application can be used to form a steering system that will remain operational upon a failure. The key points of a provisional safety case are presented, giving hope that a complete safety case is possible. This article will provide autonomous vehicle developers a view of a near term possibility for a highly automated commercial vehicle steering solution.

Abstract Articulated vehicles contribute to the major portions of cargo transport through roads. Fifth wheel (FW) is an important component in these vehicles, which acts as the bridge between tractor and trailer and is often used as a parameter to adjust the axle loads. Ride and comfort studies linked to FW position exist. However, its influence on durability is often not considered seriously. In this article, three different FW positions placed at 200 mm, 400 mm, and 600 mm in front of the rear axle are studied virtually on a 4×2 tractor with three-axle semitrailer combination. To assess the risk associated with FW movement, acceleration-based pseudo-relative damage, power spectral density (PSD), and level crossing plots are analyzed for each FW position. Further, fatigue analysis is done on the cab structural components to understand the durability. Outcome shows that the FW position has an influence in determining the cab dynamics and durability of the components to a great extent.

Differences, where they exist, are shown in Appendix A. This SAE Standard establishes a classification of materials intended for the manufacture of piston rings based on mechanical properties and the stresses that these materials are capable of withstanding. This document applies to the manufacture of piston rings up to and including 200 mm diameter for reciprocating internal combustion engines. It also applies to piston rings for compressors working under similar conditions.

The fulfillment of the strict market requirements for customers in the “off-road” vehicles segment is crucial to increase the value and reliability of the products and services available by a manufacturer of heavy-duty vehicles. The need for a product that meets these demands becomes an outstanding factor of a manufacturer, since it provides active customer care services, aiming at the preventive and/or corrective “in loco” maintenance for its vehicles and equipment. This work proposal encompasses the development, manufacturing and management, by its dealers, of a remote maintenance unit (RMU), customized and configured with all the equipment required to support active maintenance services, both preventive and corrective, in the operation/work region of the customer. Thus, the target is the minimization of the running time of its vehicles and/or equipment to the nearest service station, or even of the wait time for concluding a service.

Compact excavators are designed to perform a variety of functions within a small vehicle envelope. The vehicle size presents constraints on the structure as well as the hydraulic system. A unique open-center hydraulic system has been designed and developed which optimizes system performance, size, and cost. The hydraulic circuit was designed to provide smooth, reliable operation of as many as ten vehicle functions simultaneously.

A new oval test track will be designed, constructed and operated in a manner that will successfully pull-together representatives from virtually all of the key interests in dealing with the challenging issues of highway pavement and truck durability. With construction scheduled to begin in the Summer of 1998 and completion scheduled for late 1998 or early 1999, the mission and commitment for this venture is to pull-together the people from several state DOTs, respective universities, and, of vital importance, the truck manufacturing industry. Results from these tests, over a period of a few years, will provide answers that not only greatly improve performance of hot mix asphalt pavements in all state DOTs, but also efficiently and productively address issues of durability and wear performance of medium / heavy duty trucks and key components.

Eaton has been working on technologies for cost effective, reliable and safe Automated Mechanical Transmissions (AMTs) since the mid 1970's. The company has introduced three different systems since the late 1980's, but all three systems were constrained by the lack of precise engine speed control during shifting. With the advent of electronic engine controls the constraint has been removed and precise engine speed control during shifting can be easily accomplished. The result is a simplified system that is powerfully intelligent and fully capable of automatic shifting i.e., the transmission system determines when to shift and executes the shift without any driver inducement across the broad spectrum of truck usage. This paper discusses some of the AMTs available to the truck market, showing how the system benefits both the OEM and the end user.