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Technical Paper

CAE Approach for Light Truck Frame Durability Evaluation Due to Payload Increase

2004-11-16
2004-01-3411
The growing competition of the automotive market makes more and more necessary the reduction of development time and consequently, the increase of the capacity to quickly respond to the launching of the competitors. One of the most costly phases on the vehicle development process is the field durability test, both in function of the number of prototypes employed and the time needed to its execution. More and more diffused, the fatigue life prediction methods have played an important part in the durability analysis via CAE. Nevertheless, in order they can be reliable and really being able to reduce the development time and cost, they need to be provided with load cases that can accurately represent the field durability tests. This work presents a CAE approach used for light trucks in order to get a reasonable understanding of component durability behavior due to payload increase. In general, road load data is not available for a new payload condition.
Technical Paper

Development of Portable Self Contained Phase Shifting Digital Shearography for Composite Material Testing

2005-04-11
2005-01-0590
The use of composite materials in the automotive industry has become increasingly widespread. With this increase in use, techniques for non-destructive testing (NDT) have become more and more important. Various optical NDT inspective methods such as holography, moiré techniques, and shearography have been used for material testing. Among these methods, shearography appears to be most practical. Shearography has a simple optical setup due to its “self-referencing” system, and it is relatively insensitive against rigid-body motions. Measurements of displacement derivatives, and thus strain directly, rather than the displacement itself is achieved through this method. Therefore shearography detects defects in objects by correlating anomalies of strain which are usually easier than correlating the anomalies of the displacement itself, as in holography. To date shearography has shown potential as a NDT tool for identifying defects in small structures.
Technical Paper

Brake Pedal Feeling Comfort Analysis for Trucks with Pneumatic Brake System

2019-09-15
2019-01-2140
The brake pedal is the brake system component that the driver fundamentally has contact and through its action wait the response of the whole system. Each OEM defines during vehicle conceptualization the behavior of brake pedal that characterizes the pedal feel that in general reflects not only the characteristic from that vehicle but also from the entire brand. Technically, the term known as Pedal Feel means the relation between the force applied on the pedal, the pedal travel and the deceleration achieved by the vehicle. Such relation curves are also analyzed in conjunction with objective analysis sheets where the vehicle brake behavior is analyzed in test track considering different deceleration conditions, force and pedal travel. On technical literature, it is possible to find some data and studies considering the hydraulic brakes behavior.
Technical Paper

Development of a Commercial Truck Parabolic Leaf Spring Using CAE Simulation with Correlated Experimental Stress Analysis Results

2017-11-07
2017-36-0126
The development costs that new design requires are subject to everyday discussions and saving opportunities are mandatory. Using CAE to predict design changes can avoid excessive costs with prototypes parts, considering the high reliability those current mathematical models can provide. This paper presents the methodology used during the development of a parabolic leaf spring for the rear suspension of a commercial truck, considering mainly the parabolic profiles and stress distribution on the leaves, calculated using CAE software (ANSYS) and experimental tests to measure the actual stress on each leaf, certifying the correlation between computational calculations and real stress on the parts during bench and vehicle evaluations.
Technical Paper

Adaptive Nonlinear Model Predictive Cruise Controller: Trailer Tow Use Case

2017-03-28
2017-01-0090
Conventional cruise control systems in automotive applications are usually designed to maintain the constant speed of the vehicle based on the desired set-point. It has been shown that fuel economy while in cruise control can be improved using advanced control methods namely adopting the Model Predictive Control (MPC) technology utilizing the road grade preview information and allowance of the vehicle speed variation. This paper is focused on the extension of the Adaptive Nonlinear Model Predictive Controller (ANLMPC) reported earlier by application to the trailer tow use-case. As the connected trailer changes the aerodynamic drag and the overall vehicle mass, it may lead to the undesired downshifts for the conventional cruise controller introducing the fuel economy losses. In this work, the ANLMPC concept is extended to avoid downshifts by translating the downshift conditions to the constraints of the underlying optimization problem to be solved.
Journal Article

Legibility: Back to the Basics

2011-04-12
2011-01-0597
The objective for this study was to revisit some of the known factors that affect legibility including font characteristics, as well as, contrast polarity, luminance contrast, and color contrast under high ambient conditions as specified in SAE J1757. The study focused on older drivers due to their increased visual needs and limitations. The study was conducted in 2 phases: 1) a study of font characteristics; character height, character width, and stroke width using a central composite design. Subjects read a group of letters and numerals displayed on a laptop display using occlusion goggles. The reading time (Total Shutter Open Time or TSOT), reading errors, and a subjective Readability Rating (using a 4 point scale "Very Easy," "Easy," "Difficult," "Very Difficult") were recorded. Licensed drivers in three age groups, 25 to 44 yrs, 45 to 59 yrs, and 61 to 91 yrs participated. The response surfaces were generated and compared to the character sizes recommended in ISO 15008.
Journal Article

Cruise Controller with Fuel Optimization Based on Adaptive Nonlinear Predictive Control

2016-04-05
2016-01-0155
Automotive cruise control systems are used to automatically maintain the speed of a vehicle at a desired speed set-point. It has been shown that fuel economy while in cruise control can be improved using advanced control methods. The objective of this paper is to validate an Adaptive Nonlinear Model Predictive Controller (ANLMPC) implemented in a vehicle equiped with standard production Powertrain Control Module (PCM). Application and analysis of Model Predictive Control utilizing road grade preview information has been reported by many authors, namely for commercial vehicles. The authors reported simulations and application of linear and nonlinear MPC based on models with fixed parameters, which may lead to inaccurate results in the real world driving conditions. The significant noise factors are namely vehicle mass, actual weather conditions, fuel type, etc.
Technical Paper

Evolution of the New Ford Aerostar Impact Extruded Aluminum Wheel

1984-11-01
841694
Ford's continued effort to improve fuel economy in automotive applications has emphasized the need for lightweight components that retain all the toughness associated with Ford truck vehicle characteristics. The application of an impact extrusion process to wheel design and manufacture, for Ford Aerostar, provides strength, performance and style more efficiently than other traditional processes. It results in a valuable 33% weight saving over comparable HSLA steel wheels, and provides the customer with uncompromised value. The Ford Aerostar Impact Extruded Aluminum Wheel was designed to be of one-piece construction, manufactured from a less than 1″ thick aluminum wafer-shaped blank. The process permits manufacture in half the steps of a conventional stamped steel wheel, and eliminates extensive machining required with forged or cast aluminum wheels.
Technical Paper

Commercial vehicle pedal feeling comfort ranges definition

2020-01-13
2019-36-0016
The brake pedal is the brake system component that the driver fundamentally has contact and through its action wait the response of the whole system. Each OEM defines during vehicle conceptualization the behavior of brake pedal that characterizes the pedal feel that in general reflects not only the characteristic from that vehicle but also from the entire brand. Technically, the term known as Pedal Feel means the relation between the force applied on the pedal, the pedal travel and the deceleration achieved by the vehicle. Such relation curves are also analyzed in conjunction with objective analysis sheets where the vehicle brake behavior is analyzed in test track considering different deceleration conditions, force and pedal travel. On technical literature, it is possible to find some data and studies considering the hydraulic brakes behavior.
Technical Paper

Mass Optimization of a Front Floor Reinforcement

2020-01-13
2019-36-0149
Optimization of heavy materials like steel, in order to create a lighter vehicle, it is a major goal among most automakers, since heavy vehicles simply cannot compete with a lightweight model's fuel economy. Thinking this way, this paper shows a case study where the Size Optimization technique is applied to a front floor reinforcement. The reinforcement is used by two different vehicles, a subcompact and a crossover Sport Utility Vehicle (SUV), increasing the problem complexity. The Size Optimization technique is supported by Finite Element Method (FEM) tools. FEM in Computer Aided Engineering (CAE) is a numerical method for solving engineering problems, and its use can help to optimize prototype utilization and physical testing.
Technical Paper

A Comparative Study of Automotive System Fatigue Models Processed in the Time and Frequency Domain

2016-04-05
2016-01-0377
The objective of this paper is to demonstrate that frequency domain methods for calculating structural response and fatigue damage can be more widely applicable than previously thought. This will be demonstrated by comparing results of time domain vs. frequency domain approaches for a series of fatigue/durability problems with increasing complexity. These problems involve both static and dynamic behavior. Also, both single input and multiple correlated inputs are considered. And most important of all, a variety of non-stationary loading types have been used. All of the example problems investigated are typically found in the automotive industry, with measured loads from the field or from the proving ground.
Technical Paper

Chassis Lightweighting Hole Placement with Weldline Evaluation

2020-04-14
2020-01-0493
Vehicle weight driven design comes amid rising higher fuel efficiency standard, and must meet the criteria - pass Proving ground test events that is equivalent customer usage. CAE Fatigue analysis for proving ground (CFP) is behind a success push to digitally simulate vehicle durability performance in high fidelity. The need for vehicle weight reduction often arises late in vehicle development phases when CAE Methods, time, and tangible cost effective opportunities are limited or non-existent. It is necessary to deploy a new CAE Method to identify opportunities for light-weighting hole placement in Chassis structures to deliver a cost effective light-weighting opportunity with no impact on fatigue life. The successful application of this methodology is on truck frame, which is key structural parts for vehicle chassis to support body and suspension and powertrain.
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