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Technical Paper

Method for Preventing Contamination on Trucks Cabin Side Using CFD

Although ignored by most people not directly involved with highway and off-road commercial trucks operation the accumulation of dust and mud on cabin side can become a rather annoying issue. Besides adhering to the passengers clothes dirt contamination may also compromise driver visibility constituting a safety concern. For a truck manufacturer it can revert into quality complaints and negatively influence customers’ future buying decisions. In this context, fascia air deflectors are common devices used in truck industry to control the airflow over the cabin panels and ultimately prevent contamination deposition. This paper presents a methodology to avoid dust and mud accumulation on commercial trucks cabin doors based on the predicted airflow field by computational fluid dynamics (CFD) and a reference flow metric defined through a simple bench test.
Technical Paper

Frequency FE-Based Weld Fatigue Life Prediction of Dynamic Systems

In most aspects of mechanical design related to a motor vehicle there are two ways to treat dynamic fatigue problems. These are the time domain and the frequency domain approaches. Time domain approaches are the most common and most widely used especially in the automotive industries and accordingly it is the method of choice for the fatigue calculation of welded structures. In previous papers the frequency approach has been successful applied showing a good correlation with the life and damage estimated using a time based approach; in this paper the same comparative process has been applied but now extended specifically to welded structures. Both the frequency domain approach and time domain approach are used for numerically predicting the fatigue life of the seam welds of a thin sheet powertrain installation bracketry of a commercial truck submitted to variable amplitude loading. Predicted results are then compared with bench tests results, and their accuracy are rated.
Technical Paper

FE-Based Weld Fatigue Life Prediction of Powertrain Installation Bracketry

Mainly in the last 30 years so much research has been done on Fe-based calculation of seam welded thin-sheet structures fatigue life. However, available prediction methods have been developed for a limited range of geometries under ideal load conditions. Extrapolating to complex real world geometries and load conditions such those resultant from, for example, ground vehicles dislocation over rough surfaces, are least documented. One example of the application of seam welded thin-sheet structures in the ground vehicle industry is the powertrain installation bracketry. Such brackets are subject to variable amplitude loading sourced from powertrain and road surface irregularities and their fatigue strength is tightly dependent on the strength of their joints. In this paper, a FE-based force/moment method has been used for numerically predicting fatigue life of powertrain installation bracketry of a commercial truck submitted to variable amplitude loading.
Technical Paper

Wall Temperatures and Airflow Prediction in Automotive Headlights Utilizing the CFD Methodology

Nowadays the increase and maintenance of a car manufacturer market share is greatly influenced by the appeal its products design, wherein the headlights occupy a distinctive position. However, the headlights designers' constant search for newer and innovative designs sometimes yields difficulties regarding the thermal management of these components, requiring cautious material selection, and special care in the parabolas dimensioning and positioning of bulbs and vents in the case. This work shows how a simulation strategy based on the finite volume method can be utilized to predict the headlight airflow and plastic walls temperature distribution induced by the bulbs thermal radiation. The main goal of this modeling is to raise and treat potential temperature issues early in the development cycle, guiding the corrective design actions, and supporting the material selection and specification process.
Technical Paper

CFD Approach on Underhood Thermal Management of Passenger Cars and Trucks

This paper presents an analytical methodology developed to enhance passenger cars and trucks cooling and underhood thermal management process utilizing CFD (Computational Fluid Dynamics) technology. Aspects of vehicle frontal openings definition process based on isolated cooling package components airflow requirements are presented as well as the selection and specification of heat exchangers and fans, and the air flux and temperatures distribution management in the engine compartment.
Technical Paper

Cooling and Airflow Management Development for Trucks Considering Pass-by-Noise

A vehicle cooling system development and optimization success is strongly dependent on the prevention of recirculation zones and other areas of heat transfer and air flow concerns generated by underhood components. Traditionally, noise insulation package is defined without considering its impact on the thermal environment surrounding it. However, the airflow restriction created by the noise shields surfaces may become a huge air flow issue. This situation is usually verified on trucks designed for tropical markets and submitted to severe environments. This paper presents a development strategy coupling cooling and underhood air flow management package specification with pass-by-noise insulators design. The interaction between cooling and pass-by-noise developments must avoid the necessity of a later redesign phase. A CFD software, lab sound intensity noise source ranking tests as well as vehicle cooling testing are suggested as development tools.
Technical Paper

Pass-by-Noise Development for Trucks Considering Cooling and Airflow Management

The work carried out with external noise insulation has been demanding high importance in vehicle concept since the second External Noise Regulation in Brazil (Conama 001/ 1993). The engineering effort shall increase significantly for near future developments due to the new Regulation (Conama 272 / 2000) with more stringent limits. The effect over vehicle systems beyond noise requirements is not restricted to the addition of shields and insulators. The airflow restriction created by the noise shields surfaces may become a huge cooling issue. This situation is usually observed on trucks designed for tropical markets and submitted to severe environments. Lessons learned in a current development are the basis of the proposed methodology. Vehicle and lab sound intensity noise source ranking tests are suggested as development tools. The paper also presents a pass-by-noise development strategy that includes CAE airflow and cooling management tools.