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Technical Paper

Research on Simulation Method of Spot-weld Based on Vehicle Modal Analysis

2011-05-17
2011-01-1694
Spot-weld in most of vehicle modal analysis is modeled as a Rigid-beam, which is found that the stiffness of spot-weld can not be controlled and is highly dependent on mesh. A new simulation method of spot-weld is put forward by using Elastic-beam and modal analysis of a light bus is done. The experimental validation of real cars is completed and the results show that the simulation method of spot-weld using Elastic-beam is more accurate and effective.
Journal Article

Finite Element Model for Spot Welds Using Multi-Point Constraints and its Dynamic Characteristics

2011-05-17
2011-01-1697
In this paper, we focus on the ACM2 (Area Contact Model 2) model as a simplified spot weld model suitable for vibration analysis and reveal its dynamic characteristics. First, the theoretical background of the multi-point constraint (MPC) used in the ACM2 model is explained. Next, we examine in detail the effect of the mesh pattern surrounding a spot weld on the modal properties (natural frequency and mode shape) of a spot welded structure. Finally, an appropriate mesh size in the area of the spot weld for the ACM2 model is presented. As an example, we used two steel plates joined by three spot welds. The results show that the configuration and size of the patch (group of shell elements in the ACM2 model) significantly affect the modal properties of the model. When the centers of the patch and the solid element that represent the spot weld are coincident, the natural frequencies monotonically increase with the patch size.
Technical Paper

Simulation of Airborne Path Attenuation of Partial Enclosures

2011-05-17
2011-01-1720
Partial enclosures are a very common way to reduce noise emissions from machinery. However, partial enclosures exhibit complex acoustic behavior that is difficult to predict. The boundary element method (BEM) was used to model the airborne path of a partial enclosure. Simulation results were compared to measurement with good agreement. Special attention is given to the determination of negative insertion loss. It is demonstrated that the enclosure insertion loss will be negative at the Helmholtz frequencies for the enclosure.
Technical Paper

Understanding the Effect of Spot-Weld/Bolt Joint Distribution on the Sound Radiation from Panel Structures

2011-05-17
2011-01-1723
It is well known that sound radiation from a rectangular panel can be significantly affected by its boundary condition. However, most of the existing investigations are primarily focused on sound radiation from plates with simply supported boundary conditions. The objective of this paper is to study the effect on sound radiation of the boundary supporting conditions generally specified in the form of discrete and/or distributed restraining springs. This will have practical implications. For example, in automotive NVH design, it is of interest to understand how the sound radiation from a body panel can be affected by the number and distribution of spot-welds. It is demonstrated through numerical examples that the distribution of spot-welds can be tuned or optimized, like other conventional design parameters, to achieve maximum sound reduction.
Technical Paper

Multi Layered Maps for Enhanced Environmental Perception

2011-09-13
2011-01-2244
Traditionally, an in-vehicle map consists of only one type of data, tailored for a single user function. For example, the navigation maps contain spatial information about the roads. On the other hand, a map built for adaptive cruise control use consists of the detected vehicles and their properties. In autonomous vehicle research, the maps are often built up as an occupancy grid where areas are classified as passable or impassable. Using these kinds of maps separately, however, is not enough to support the traffic safety enhancing and advanced driver assistance systems of today and tomorrow. Instead of using separate systems to handle individual safety or planning tasks, information could be stored in one shared map containing several correlated layers of information. Map information can be collected by any number of different sensor devices, and fusion algorithms can be used to enhance the quality of the information.
Journal Article

Modeling of Thermophoretic Soot Deposition and Hydrocarbon Condensation in EGR Coolers

2009-06-15
2009-01-1939
EGR coolers are effective to reduce NOx emissions from diesel engines due to lower intake charge temperature. EGR cooler fouling reduces heat transfer capacity of the cooler significantly and increases pressure drop across the cooler. Engine coolant provided at 40–90 C is used to cool EGR coolers. The presence of a cold surface in the cooler causes particulate soot deposition and hydrocarbon condensation. The experimental data also indicates that the fouling is mainly caused by soot and hydrocarbons. In this study, a 1-D model is extended to simulate particulate soot and hydrocarbon deposition on a concentric tube EGR cooler with a constant wall temperature. The soot deposition caused by thermophoresis phenomena is taken into account the model. Condensation of a wide range of hydrocarbon molecules are also modeled but the results show condensation of only heavy molecules at coolant temperature.
Technical Paper

The Effect of Forced Cool Down on Cold Start Test Repeatability

2009-06-15
2009-01-1976
Increasing the number of cold-start engine cycles which could be run in any one day would greatly improve the productivity of an engine test facility. However with the introduction of forced cooling procedures there is the inherent risk that test-to-test repeatability will be affected. Therefore an investigation into the effects caused by forced cooling on fuel consumption and the temperature distribution through the engine and fluids is essential. Testing was completed on a 2.4 litre diesel engine running a cold NEDC. The test facility utilises a basic ventilation system, which draws in external ambient air, which is forced past the engine and then drawn out of the cell. This can be supplemented with the use of a spot cooling fan. The forced cool down resulted in a much quicker cool down which was further reduced with spot cooling, in the region of 25% reduction.
Technical Paper

Acoustical Study of Micro- Perforated Plates for Vehicle Applications

2009-05-19
2009-01-2037
Micro-perforated plate (MPP) absorbers are perforated plates with holes typically in the sub mm range and perforation ratios around 1%. The values are typical for applications in air at standard temperature and pressure (STP). The underlying acoustic principle is simple, it is to create a surface with a built in damping which effectively absorbs sound waves. To achieve this, the acoustic impedance of a MPP absorber is normally tuned to be of the order of the characteristic wave impedance in the medium (~ 400 Pa*s/m in air at STP). The traditional application for MPP absorbers has been building acoustics often combined with a so called panel absorber, to create an absorption peak at a selected frequency. However, MPP absorbers made of metal could also be used for noise control close to or at the source in many vehicle applications.
Technical Paper

Boundary Conditions Affecting Gear Whine of a Gearbox Housing Acting as a Structural Member

2009-05-19
2009-01-2031
Vehicle cabin gear whine levels have long been known to contribute to driver annoyance and perceptions of poor quality in passenger cars and trucks, as well as contributing to operator fatigue in helicopters and heavy machinery. For material handling vehicles, radiated gear whine not only influences annoyance and fatigue of operators, but also creates unwanted noise in the operational environment such as warehouses and plants. Upfront management of gear whine levels using predictive software tools is therefore critical for satisfactory design of gearboxes used in such applications. One challenge, however, is selecting the proper boundary conditions for modeling a gearbox acting as a load-bearing structural member used in the material handling vehicles.
Technical Paper

Simple Test Method for Squeak & Rattle Evaluation of Door Trim by Using Statically Repeated Loading Robot Arm

2009-05-19
2009-01-2112
Recently, major car maker is specified squeak and rattle test method for subsystems or components by objective method. Generally these test method is focused on vibration environmental conditions. Especially, door trim which is located close to occupant is required additional test for squeak and rattle which is produced by occupant's interaction with door trim. To evaluate this condition, generally it can be tested by subjective method such as striking or pushing and twisting several positions of door trim. Dosing so is very time consuming and including variation results as different decisions. So, this paper suggest a new approach for evaluating squeak and rattle which is relating occupant contacting conditions to interior part, especially interior door trim. Multi-axis robot arm is examined to push automatically several points of door trim.
Technical Paper

Analytical and Experimental Approach to Acoustic Package Design

2009-05-19
2009-01-2119
The interior noise signature of passenger vehicles is a significant contributor to a customer's perception of quality. The vehicle acoustic package can be an important piece to the acoustic signature, and can be utilized not just to reduce the sound levels inside the vehicle but also to shape the sound such that it meets the expectations of the customer. For this reason the definition, design, and development of an acoustic package can be vital to meeting vehicle-level acoustic targets. In many situations this development is conducted experimentally, requiring the availability of prototype vehicles and acoustic package components. Of more value is the ability to develop components early in the design phase, leveraging analytical tools to define component-level requirements and targets to meet the vehicle-level targets, and ultimately meet the final customer expectations.
Technical Paper

Application of Tuned Mass Damper to Address Discrete Excitation Away From Primary Resonance Frequency of a Structure

2009-05-19
2009-01-2125
Tuned mass dampers (TMDs) or vibration absorbers are widely used in the industry to address various NVH issues, wherein, tactile-vibration or noise mitigation is desired. TMDs can be classified into two categories, namely, tuned-to-resonance and tuned-to-discrete-excitation. An overwhelming majority of TMD applications found in the industry belong to the tuned-to-resonance category, so much of information is available on design considerations of such dampers; however, little is published regarding design considerations of dampers tuned-to-discrete-excitation. During this study, a problem was solved that occurred at a discrete excitation frequency away from the primary resonance frequency of a steering column-wheel assembly. A solution was developed in multiple stages. First the effects of various factors such as mass and damping were analyzed by using a closed-form solution.
Technical Paper

Research on Pb-free Electroless Ni Plating for Pistons of General-purpose Engines

2009-11-03
2009-32-0065
Ni-P-B plating applied to the piston of a general-purpose engine with an aluminum alloy cylinder contains some thousands ppm of Pb, which is used as the treating liquid stabilizer, in its plating. But, Pb is considered an environmental hazardous and it is necessary to reduce its amount in the plating. Our previous researches, however, reveal that Pb plays a major role in wear and seizure resistance. In order to obtain the sliding properties equivalent to Ni-P-B plating that contains Pb, therefore, it is necessary to review the composition of Ni-P-B plating. In this research, therefore, we specifically focus on the plating hardness of Ni-2%P plating subject to the temperature environment in which the piston operates, and discuss whether the same sliding effects as that of the Pb containing Ni-P-B plating is obtainable by restraining the hardness decrease.
Technical Paper

Development of High Fatigue Strength Valve Spring Using Control of White Layer by Nitriding

2009-11-03
2009-32-0082
For the requirements of high power output, lightweight and improved fuel consumption of motorcycles to respond to global environmental needs, high fatigue strength to cope with high stress is becoming more important than ever for valve springs. To satisfy such needs, a new alloy steel that softens less in tempering (1),(2) and nitriding that increases surface hardness of valve springs has been developed using oil-tempered silicone-chrome steel wire as the base material. Also, with regards to shot-peening to create compression residual stress on the surface, studies are being performed for multi-stage and high-hardness peening. The research reported in this paper is aimed at an increase of internal hardness after nitriding while maintaining the cold-coiling-ability by adding elements that reduce softening from tempering while reducing non-dissolved carbide in the material.
Technical Paper

AN OPTIMAL SOLUTION THROUGH LEAN MANUFACTURING USING VALUE STREAM MAPPING TOWARDS EFFICIENT PRODUCTION FOR A WORLD- CLASS AUTOMOBILE BRAKES MANUFACTURING COMPANY

2009-12-13
2009-28-0054
Today, numerous companies have a major opportunity to reduce their costs and customer lead time and cycle time through the application of Lean Manufacturing processes. In recent years, almost every manufacturing industry has been trying to get ‘lean’. Lean thinking represents a set of principles and techniques for the identification and elimination of wastages in manufacturing and administrative processes. Value Stream Mapping (VSM) which is one of the lean manufacturing approaches has emerged as the preferred way to support and implement the lean approach. VSM is a helpful tool to identify the waste and improvement areas. VSM enables a company to see the entire process in both its current and desired future state, and develop the road map that prioritises the projects or tasks to bridge the gap between the current state and the future (lean) state.
Technical Paper

LASER SURFACE HARDENING OF CRANKSHAFT

2009-12-13
2009-28-0053
The present work involves systematic study on identification of process parameters and processing conditions for effective laser surface-hardening of automotive crankshaft and its implementation in the industry, utilizing a diode laser integrated to a 6-axis robot and a turn/tilt table. The crankshaft chosen was made of low-alloyed 0.52% C steel and required hardening at two contact regions of bearing/flange seat areas and a pin area (on a different axis than the actual shaft). The subjected areas had features like oil holes, sharp corners and wide areas. The target was to develop laser hardening process resulting in hardened case-depth of above 200 µm with a hardness of 500 - 650 HV at different locations mentioned. Additionally, It was targeted to minimize the processing time and also eliminate any post process machining operations.
Technical Paper

Numerical Studies on the Effect of Cooling Vent Setting and Solar Radiation on Air Flow and Temperature Distribution in a Passenger Car

2009-12-13
2009-28-0048
Owing to the dynamic life style, considerable time is spent in traveling. Consequently, the demand for thermal comfort of passengers in vehicles has increased. And, to provide thermal comfort, the vehicles are equipped with Heating, Ventilation and Air Conditioning (HVAC) systems. However, the tendency to use more glass in vehicle styling, fuel-economy constraints, environmentally safe refrigerants and reduced condenser air flow, particularly at idling conditions, hampers the goal of achieving the desired thermal comfort of passengers. Thus, it is imperative to evaluate the performance of the HVAC units and the effect of their delivery systems to predict the impact on the airflow, temperature distribution and thermal comfort of passengers. CFD simulations have gained importance for such evaluations, which include both steady state and transient calculations.
Technical Paper

Battle Tank Fuel Capacity (Total Volume) Monitoring system

2009-12-13
2009-28-0051
As information is going to be a strategic weapon in all future warfare, every country is taking giant steps to access the accurate information about the combat situation so that right decision is taken at right time A Battle Tank can effectively annihilate the enemy targets, until it has Ammunition Stocks and can successfully maneuver through the enemy locations until the fuel lasts, thus replenishing the same is a foremost important winning factor in war. So, the Information about the exact quantity of Fuel, Ammunition available in the Fighting vehicle (Tanks) at any point of time dictates its deployability into the deeper enemy territories. Worldwide, all Main Battle Tanks (MBT), are fitted with a capacitance based fuel level indicating system. The difficulty is that it can indicate only the volume of a particular fuel tank to which it is fitted, where as a MBT may have many fuel tanks, to utilize the space wherever possible.
Technical Paper

Simulation and Validation of Passenger Compartment Soaking and Cooling under Solar Load

2009-12-13
2009-28-0050
Predicting the thermal comfort of the passenger compartment or the vehicle cabin using computational fluid dynamics (CFD) analysis helps reduce the cost and time of a heating ventilation and air-conditioning (HVAC) system development in any new vehicle program. This paper presents the simulation results of cabin soaking and cooling analysis done on an actual sports utility vehicle (SUV) prototype under constant solar load using the commercial CFD package Fluent™. These results are compared with test results. Cabin cooling and soaking analysis for a closed loop system that would include the HVAC system, the IP duct and the cabin with the air-conditioner (AC) operating in the recirculation mode is simulated. The heat rejected in the evaporator is assumed to be constant and this closed loop system analysis eliminates the need to be dependent on test results for input conditions like air flow rate and air temperature at duct inlet ports.
Technical Paper

Development and Validation of Utility Matrix for Automotive Interiors in Real World Usage

2009-01-21
2009-26-0072
As the real world usage profile of customers is becoming increasingly dynamic the need for more utility features in interior parts of vehicle has increased. The main purpose of the study is to analyze how the changing customer style actually influences the volume requirement of the utility spaces i.e. at the glove box, console door pocket etc. In the present study, an exhaustive list of utilities, and a utility matrix based on the user characteristics for automotive interiors is developed. Based on customer reviews on the web and expert opinions, seven user profiles were defined. The selection matrix is arrived at by using the usability index, accessibility index and the disbursement index. The matrix is evaluated using statistical methods and validated for real world usage. The selection matrix is used to identify relatively important utility features and preferred locations in automotive interior parts.
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