Refine Your Search




Search Results

Technical Paper

Optimization of Front End Cooling Module for Commercial Vehicle Using CFD Approach

Assessment of cooling performance in the design stage of vehicle allows a reduction in the number of needed prototypes and reduces the overall design cycle time. Frontend cooling and thermal management play an essential role in the early stages of commercial vehicle design. Sufficient airflow needs to be available for adequate cooling of the under-hood components. The amount of air mass flow depends on the under-hood geometry details, positioning and size of the grilles, fan operation and the positioning of the other components. Thermal performance depends on the selection of heat exchanger. This paper describes the effects of several design actions on engine cooling performance of a commercial vehicle with the help of Computational Fluid Dynamics (CFD) simulation tool Fluent™. Front of vehicle design is captured in detailed FE model, considering front bumper, grille, cabin, cargo and surrounding under-hood and underbody components.
Technical Paper

Numerical and Experimental Investigation of Residual Stresses in Cold Formed Truck Frame Rail Sections

Cold formed carbon steel C sections are often employed as load carrying structural members in heavy commercial trucks. The cold forming operations employed during the making of these members generate certain amount of residual stresses throughout the sections. As the residual stresses play a significant role in determining the structural behavior of truck frame rail members, a careful assessment of residual stresses resulting from cold forming operation is needed. In the present investigation, residual stresses in frame rail corner sections were numerically predicted with the help of non-linear Finite Element (FE) analysis in ABAQUS and compared with the experimentally measured residual stress values using X-ray diffraction technique. It has been observed that the numerically predicted residual stresses are in agreement with the experimentally measured residual stresses in forming direction.
Technical Paper

Capacity of a Welded Structure of Direct-Quenched Ultra-High-Strength Structural Steels

Abstract The development of weldable high-strength and wear-resistant steels have made modern structures such as booms and mobile equipment possible. These sorts of novel and effective designs could not be constructed with traditional mild steel. Unfortunately, the use of these novel steels requires proper design, and there is no practical design code for these novel steels. This paper addresses stability issues, which are important considerations for designs with high-strength steels, and the properties of the heat-affected zone, which may require special attention. Fatigue design is also discussed in this paper, and the importance of the weld quality is highlighted, along with discussions on which details in the weld are the most important. By comparing the test results with the classical load limit solution, it is determined that full plastic capacity is reached and that the samples display good strain properties.
Technical Paper

Simulation of Impact to Dumper Bodies Made of Modern QT-Steels

Abstract The use of modern quenched and tempered steels in dumper bodies to reduce weight to increase the payload and reduce the fuel consumption is briefly discussed. Modern quenched and tempered steels in combination with adopted design concept will further increase weight savings of the dumper body. Use of these materials may lead to 4 times longer wear life than ordinary steels. One of the main load cases for a dumper body is impact of an object, i.e. boulders and rocks, into the body. A well-proven test setup is used to develop a model to predict failure and depth of the dent after the impact. A material model with damage mechanic was utilized to predict fracture. The developed model was used to study the effect of the geometry of the impacting object, thickness of the plate and unconstrained plate field. The model was also implemented in larger model and compared with a full scale test of dumper body.
Technical Paper

Structural Strength Simulations of Ladder Frame Chassis for Light Agriculture Truck

Abstract A vehicle of interest in this paper was a light agriculture truck. In order to obtain reliable predictions of stress generated in the frame under loads, a combination of experimental tests and computer simulations was arranged. Since the focused deformations were bending and torsion modes, the truck driven up one-wheel ramp and two-wheel ramp was investigated. Strains results obtained from both tests and simulations were compared. The discussions and conclusions were made regarding the accuracy and further improvements of the simulations.
Technical Paper

Techniques for Aerodynamic Analysis of Cornering Vehicles

Abstract When a vehicle travels through a corner it can experience a significant change in aerodynamic performance due to the curved path of its motion. The yaw angle of the flow will vary along its length and the relative velocity of the flow will increase with distance from the central axis of its rotation. Aerodynamic analysis of vehicles in the cornering condition is an important design parameter, particularly in motorsport. Most racing-cars are designed to produce downforce that will compromise straight-line speed to allow large gains to be made in the corners. Despite the cornering condition being important, aerodynamicists are restricted in their ability to replicate the condition experimentally. Whirling arms, rotary rigs, curved test sections and bent wind tunnel models are experimental techniques capable of replicating some aspects of the cornering condition, but are all compromised solutions.
Technical Paper

Research on Torsional Characteristic of Separate Frame Construction for a Light Off-Road Vehicle

Abstract A key problem of designing a light off-road vehicle with separate frame construction is to improve its torsional characteristic, which has a significant influence on the performance of the vehicle. Inevitably, a certain distortion of the body would be produced by the vibration and impact passing from the road. In present research, an analysis model of light off-road vehicle is established based on the theories and methods of finite element (FEM). The static stiffness of the body is simulated and the deformation of openings on the body, mainly the windows and the doors of the vehicle is studied. On the working conditions of torsion and braking combination, torsion and cornering combination, diagonal dangling, ultimate torsion of unilateral wheels and diagonal wheels, the static strength of separate frame construction is studied as well. The stress concentration regions are obtained according to the results of simulation.
Technical Paper

Innovative Door Design for Commercial Vehicles

Abstract Design of body structures for commercial vehicles differs significantly from automotive due to government, design and usage requirements. Specifically, heavy truck doors are not required to meet side impact requirements due to their height off the ground as compared to automobiles. However, heavy truck doors are subjected to higher loads, longer life, and cannot experience permanent deformation from overload events. Aluminum has been used intensively in commercial vehicle doors and cab structures for over 50 years by several different manufacturers in North America. It has been only in the last few years that aluminum has appeared in automotive door structures other than in high-end luxury vehicles. Commercial vehicle customers are expecting the same features found in premium automobiles resulting in opportunities to learn from each other's designs. In order to optimize the strength and weight of a commercial vehicle door, a new aluminum intensive structure was developed.
Technical Paper

Effects of Liquid Cargo on Lateral Stability of B-Train Combination

Abstract Road train vehicles have been applied as one of the common and efficient ways for transportation of goods, specifically hazardous liquid cargos, in different nations. These vehicles have a wide variety of lengths and towing systems such as the fifth wheel or the dolly draw-bar. Based upon specific regulations, they could be authorized to move on specific roads. In order to avoid hazard and danger in case of accidents, safety performance of a B-train vehicle as a specific type of road train vehicles is investigated in this paper. A Multi-Body Dynamic (MBD) model, which consists of a prime mover and two trailers coupled by fifth wheels, are simulated in the initial phase of the study. The developed dynamic model is capable of simulating required tests as well as the SAE lane change, along with a constant radius turn for the purpose of roll and yaw stability analysis and safety evaluation. The effects of variation of the fluid fill level are considered in this research.
Technical Paper

Fluid - Structure Interaction Analysis and Optimization of an Automotive Component

Abstract This paper discusses the behavior of a flexible flap at the rear end of a generic car model under aerodynamic loads. A strong bidirectional coupling between the flap's deflection and the flow field exists which requires this system to be simulated in a coupled fluid-structure manner. A coupled transient aerodynamic and structural simulation is performed for a generic car model with a flexible/deformable flap at the rear end. An automatic workflow is established which generates new flap designs, derived from an initial flap design by applying a mesh deformation technology, and performs the coupled fluid-structure interaction analysis. For each shape variation, the flap's maximum displacement is monitored and used to classify the individual flap designs. This process allows for design of experiment (DOE) studies in an automated manner. Several shape variations of the flap and their impacts on the maximum deflection are investigated.
Journal Article

Components Durability, Reliability and Uncertainty Assessments Based on Fatigue Failure Data

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.
Technical Paper

Design of an Aluminum Truck Body Mounted on Chassis for Dry Cargo

The truck body on chassis for dry freight applies to several types of goods, including packagings, broken or unitized cargoes. In Brazil, this equipment is traditionally made of wood and recently of steel. Moreover, in overseas countries the manufacturing of aluminium bodies is quite common (mainly in Europe and the United States), for economic, operational and environmental reasons, such as: weight reduction and resulting increase in payload capacity of the vehicle; easy manufacturing and repair; recyclability of the material used. This paper presents the main features and technical requirements from the Design of a Aluminium Truck Body mounted on a 3-axle truck, with 23 tons of deadweight (Gross Weight) and 5.4m of distance between axes.
Technical Paper

The Current State of Pre-Formed versus Bulk Cavity Filler Technologies in the Automotive, Medium Duty and Heavy Truck Markets

The use of acoustic cavity fillers to prevent the propagation of air borne and structure borne noise, water and dust into the interior spaces of vehicle structures has been in practice for many years. Various technologies are available to OEMs to provide sealing that will prevent water and dust penetration, maximize performance of vehicle HVAC systems, and minimize the propagation of noise into a vehicle under operating conditions. The current state of the application of these technologies in the automotive, medium duty and heavy duty truck markets will be reviewed. Comparisons will be drawn between two categories of cavity fillers: pre-formed heat reactive expandable parts; and bulk applied chemically reacting polyurethane foam. Typical OEM material requirements will be discussed for these technologies. The pros and cons of these competing technologies, as well as their acoustic performance applied to a full vehicle will be considered.
Technical Paper

Durability Analysis of a Bus by Virtual Test Model (VTM)

In this work, durability of the bus structure is evaluated with a Virtual Test Model (VTM).Full vehicle Multi Body Dynamics (MBD) model of the bus is built, with inclusion of flexibility of the bus structure to capture structural modes. Component mode synthesis method is used for creation of flexible model for use in MBD. Load extraction is done by performing MBD analysis with measured wheel inputs. Modal Superposition Method (MSM) is employed in FE along with these extracted loads for calculation of modal transient dynamic stress response of the structure. e-N based fatigue life is estimated. The estimated fatigue life from the modal superposition method show good correlation with the physical test results done in 6-poster test rig.
Technical Paper

Evaluation of Structural Strength of Flatbed Trailer for Service Loading Conditions

Commercial vehicle payload depends on the client for which the vehicle fleet owner is operating. Load carriers like flatbed trailer offer the flexibility to be loaded with a large number of light payloads or a few numbers of massive payloads. Such load carriers have to be evaluated for various possibilities of loading patterns that could happen in the market. The objective of this work is to evaluate flatbed trailer for its structural strength for different customer application cases, using computer simulation. Structural load cases due to payloads like containers, steel coils and cement bags are arrived at. Static structural analysis using MSC Nastran is performed to evaluate for the worst customer loading pattern from structural stress point of view. This paper also describes a simplified method for simulating the effect of trailer suspension, tractor suspension and the fifth-wheel coupling in the analysis whose detailed modeling is not possible at the concept level.
Technical Paper

Improvements in the Fatigue Assessment of Large Welded Structures Using the Nominal Stress Approach

By the fatigue assessment of large welded steel structures such as construction machines structures, the calculation engineer is confronted with a difficulty: the local stress approaches with fictitious notch radius that are very accurate cannot be used on the global structure because of the current computer limitations. Only a nominal stress can be estimated on the whole structure. The accuracy of the current commercial code methods that are using the nominal stress approach is not satisfying for most of the cases. The major problems are the following: only one SN-Curve (FAT-class) can be chosen for a weld the stress used for the calculation is based on the critical plane concept, not taking into account the direction of the weld (anisotropy of notch effects) and the geometrical weld parameters (e.g. weld throat thickness and penetration) choice of the FAT-class when the structural detail is not available in the IIW guideline.
Technical Paper

Frame Flexibility Influence on Commercial Vehicle Performance

Looking for fuel efficiency and improvement of the load capacity, new truck designs are targeting chassis weight reduction. As a consequence, the frame can become less stiff, and its higher flexibility can affect the vehicle handling and NVH performance. This paper presents a study of the effects of the frame compliance in regard to the vehicle dynamic behavior.
Technical Paper

Stress Analysis and Validation of Superstructure of 15-Meter Long Bus under Normal Operation

The strength of the superstructure of a bus is very critical to the safety of passengers, both in normal operation and in the event of accident. During the normal operation, the structure of the bus is subjected to several loads, which may be induced by its inertia during vehicle maneuvering (i.e. braking and cornering) or by external loads from the road (i.e. crossing over a speed bump). Moreover, there is a substantial possibility that these loads may lead to a structural failure. Hence, it is necessary to determine stresses occurred in the bus's superstructure to ensure its integrity under these driving scenarios. This paper presents techniques implemented to analyze stresses on the superstructure of a newly designed 15-meter long bus subjected to loads previously mentioned using Finite Element Method (FEM). The stress analysis technique used in each scenario is selected based upon the frequency intensity of load excitations and the dynamic responses of the structure.
Technical Paper

Strength Analysis of a Semi-Trailer Tractor Frame

According to the 3 Dimension model of the side member frame, a finite element analysis (FEA) model of semi-trailer tractor frame was established and the approach of applying loads and constraints was discussed. Then the frame stress was analyzed under four working conditions as well as the eigen frequency was calculated too. It was found that the maximum stress appeared on the rear channel side-rail under the bending and twisting condition, however it still meets the strength requirements. Natural vibration frequency is far away from the exciting force's frequency such as the suspension vibration and the engine incentive. The harmonic analysis results shows that the significant stress appeared on the connection part of the channel side - rail and the second cross beam, the balance beam axis, tubular cross member.
Technical Paper

Derivation of Extreme Static Durability Load Cases for FEA Based Vehicle Strength Evaluation

Validation of vehicle structure by use of finite element analysis is at the core of reduction of product development time. In the early phase of validation it is required to evaluate the strength of the vehicle structure to account for the loading during physical validation and service loading. In service the vehicle is subjected to variable loads. These act upon the components that originate from road roughness, maneuvers and power train loads. All systems in the vehicle represent more or less complicated elastic structures subjected to time varying loads. A time domain dynamic assessment of the vehicle structure is time consuming and expensive. Also in the early phase of design wherein several design iterations need to be carried out for design validation, it is practically impossible to conduct a dynamic analysis and fatigue life assessment. Extreme static load cases are traditionally being used for this process.