Refine Your Search

Topic

Author

Affiliation

Search Results

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

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.
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

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

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

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

Laser Welding of Advanced High Strength Steels for Tailor Welded Blank (TWB) Applications

2009-12-13
2009-28-0012
One of the most popular weight reduction strategies in auto bodies is usage of tailor welded blanks (TWB). TWBs with high-strength low-alloy steels and advanced high-strength steels (AHSS) offer possibility of significant weight reduction. In the present work laser welding studies were carried out to fabricate TWB's involving 1.6 mm thickness AHSS DP 590 (dual phase steel) and 0.8 mm thickness conventional IF (interstitial free) steel in different combinations and characterized for their metallurgical and formability characteristics. Fusion zone microhardness was varying with change in material combination. While DP590-DP590 and IF-IF have shown fusion hardness of 300-350HV and 150-180HV, respectively, the dissimilar DP590-IF showed a fusion zone hardness of 250-330HV.Beam offsetting towards the thinner side has reduced the peak hardness. Microstructural analysis revealed mixture of martensite and refined ferrite in the fusion zone of dissimilar welds.
Technical Paper

Process Simulation Integration in Product Design

2009-01-21
2009-26-0089
The effect of processing parameters on the material properties is an important design consideration in plastic part design. The process may cause anisotropic properties due to matrix and fiber orientation, develop internal stresses during cooling, cause thickness variation etc. These effects if not considered in the product design and analysis, may result in premature product failure, reduced safety factor, fit and finish issues or higher costs and weight due to over design. Injection molded long glass polypropylene and blow molded PC/ABS have been used in automotive structural parts requiring to meet stringent static and dynamic loads as per the regulatory legislation. This paper demonstrates the use of injection molding and blow molding process simulation to incorporate the process effect on material and structure properties.
Technical Paper

The Challenge of Achieving Euro 4 Emissions on Sports Utility Vehicle Fitted With 2.2l CRDe Engine

2009-01-21
2009-26-0023
With newer emission norms getting introduced, OEMs are struggling hard to achieve those norms. This is because selection of appropriate technology for stringent emission norms has to be ensured in order to control higher costs and also to control adverse affect on fuel consumption. This paper briefs about the real life experience in developing Euro 4 emissions on a Sports Utility Vehicle (SUV) fitted with 2.2 liter CRDe engine. The base vehicle used is BSIII emission complaint. Efforts were made to optimize the overall emission system without use of any particle trapping device in the exhaust and with conventional air intake system. Steady and transient operating speeds of the driving cycle were optimized through common rail technology. Maximum benefits from common rail technology were captured which also were assisted by efficient Exhaust Gas Recirculation (EGR) cooling and intercooling.
Technical Paper

Development of Prediction Method of Static Torque Sharing Distribution of Planetary Gear Sets Generated by Manufacturing Error Distribution

2011-04-12
2011-01-0719
This paper discusses a method of predicting the torque distribution on planet gears originating in manufacturing errors, which is necessary for appropriate strength design of the gears in planetary gear sets. First, an expression of relation between manufacturing errors and the torque on the planet gears in a normal n-planet planetary gear set was derived. As a result, an equation expressing the distribution of torque to the planet gears was obtained. Tests were conducted to verify the validity of the equation in the case of a 4-planet planetary gear set. In order to predict the distribution of torque, it was necessary to estimate the stiffness of the planetary gear set that was the subject of the relational expression. These stiffness values were calculated by numerical analysis using a 3D FEM, into which blueprint values and material property values were input.
Technical Paper

Ultimate Load Capacity of Spot Welds Made of Ultra High Strength Steels

2011-04-12
2011-01-0788
Spot welds have two separation modes: interfacial and button pullout. Most of existing publications [8,9,10,11,12] focused on button pullout. This is because for the same sheet metal and gage combination, button pullout leads to higher separation load than interfacial separation. With the push for lighter vehicles, high strength and ultra high strength steels are used. To further reduce mass, welding flanges are getting narrower. The welding tips are getting smaller. The weld nugget diameters are smaller as a result. The separation mode for certain load cases is no longer nugget pullout, but interfacial instead. This lowers the weld's maximum load capacity. In order for CAE simulated prediction to correlate to physical behaviors of vehicle structures, it is important to define and reconfirm separation criteria. New tests and analyses are necessary.
Technical Paper

CAE based ‘Multi Objective Optimization approach for Spot Weld Connections Layout’ in Automotive Structure

2011-04-12
2011-01-0794
Spot weld connections are used extensively in the automotive industry to join panels of automotive structures. Spot weld connections play a very vital role in the overall structural rigidity and integrity of the Body in White. The spot weld connections and layout have direct impact on functionability of automotive structure and capital investment for robots, guns and operators. There is continuous pressure on automotive engineers to reduce the number of spot weld connections in a structure without compromising on the structural performance across various disciplines such as crash, NVH & durability. Hence the need is felt to develop a generic and systematic CAE simulation procedure which will guide the designer towards arriving at an optimum design, with minimum number of spot weld connections, which meet all the performance requirements of the structure.
Technical Paper

Welding Automobile Body Without Expulsion

2011-04-12
2011-01-0776
Each automobile body contains 4,500 to 6,500 spot welds joining its body components together. The quality of these welds directly influences the rigidity and integrity of the body. Because of this, producing good welds and monitoring the weld quality in real time with non-destructive testing method is of the utmost importance to the automotive industry. This paper describes a method that consistently produces good welds and monitors the quality of weld in real time. An experiment was performed to prove the soundness of this concept. The result of this experiment is presented in the later part of the paper.
Technical Paper

The Effect of Strain on Stainless Steel Surface Finish

2011-04-12
2011-01-0774
The bright surface finish of exterior automotive moldings made from stainless steel can become hazed and reflections distorted as a result of forming done during the manufacturing processes. Bright moldings are frequently used to give styling differentiation accents to vehicle exteriors. Stainless steel provides cost effective differentiation with a material that is durable and relatively easy to form to shapes desired by the stylist. Because of the desirable attributes of stainless steel, an understanding of the threshold of unacceptable surface appearance is necessary to maximize showroom appeal and avoid customer complaints that result in warranty claims. This paper quantifies the effect that manufacturing strain and strain rate have on the surface finish of 436M2 stainless steel. Controlled experiments were conducted on production grade stainless steel strips subjected to a variety of strain and strain rates typical of manufacturing processes.
Technical Paper

Dimensional Quality Control of Repeated Molded Polymer Battery Cell Housings in Automotive Energy Systems

2011-04-12
2011-01-0244
Current manufacture of alternative energy sources for automobiles, such as fuel cells and lithium-ion batteries, uses repeating energy modules to achieve targeted balances of power and weight for varying types of vehicles. Specifically for lithium-ion batteries, tens to hundreds of identical plastic parts are assembled in a repeating fashion; this assembly of parts requires complex dimensional planning and high degrees of quality control. This paper will address the aspects of dimensional quality for repeated, injection molded thermoplastic battery components and will include the following: First, dimensional variation associated with thermoplastic components is considered. Sources of variation include the injection molding process, tooling or mold, lot-to-lot material differences, and varying types of environmental exposure. Second, mold tuning and cavity matching between molds for multi-cavity production will be analyzed.
Technical Paper

Measurement of Strain Distribution for Hole Expansion with Digital Image Correlation (DIC) System

2011-04-12
2011-01-0993
Abstract Advanced high strength steels (AHSS) are increasingly used in automotive industry. A major issue for AHSS stamping is edge cracking. This failure mode is difficult to predict by conventional forming limit curve (FLC). The material edge stretchability is mainly evaluated using the hole expansion test. In this study, digital Image Correlation (DIC) is applied for strain measurement. DIC is a non-contact, full field, high accuracy and direct measurement technique that provides more detailed information for the evolution of strains on the sheet surface. Tests were conducted for five AHSS and nine cases. This paper will explain in detail the DIC technique and its results.
X