Refine Your Search

Topic

Author

Affiliation

Search Results

Technical Paper

Errors in the Driveline System Balancing Process

2001-04-30
2001-01-1504
Single-plane balancing is a very well-understood process, whereby an imbalance vector is determined and then opposed by a similar vector of equal magnitude but 180° out of phase. This is used in many situations to improve machine performance, vibration, noise etc. However, there is inherent in this process a sensitivity to errors of measurement and correction, since a large imbalance vector and the equally large correction vector must be of exactly equal magnitude and exactly 180° apart for perfect balance. This paper examines the effect of errors in measurement of the initial imbalance and correction of it on the residual balance of automotive drivelines. In particular, it examines the effects of the errors present in a system whereby a system balance correction is made, on a driveline assembly, at discrete points around a given plane (at bolt locations). Errors occur in measurement of vibration, in calculating correction masses and in applying those correction masses.
Technical Paper

Experimental Determination of Automotive System Response Characteristics

2001-04-30
2001-01-1477
Vehicle NVH performance is significantly affected by the dynamics of various primary systems. In the automotive industry, different design activities or vendors are responsible for designing various different systems simultaneously. Therefore, it is highly desirable to gain a better understanding of the individual system characteristics and the interaction between the primary systems to achieve a desirable overall NVH performance. Unfortunately, it is usually quite difficult to construct a proper fixture to accurately measure and quantify the actual uncoupled system characteristics. This paper examines an alternate approach of applying the FRF-based substructuring method to back-calculate the system response characteristics from the full vehicle system measurements. The results are then used to forward-compute the dynamic response of the vehicle, which are also validated by comparison to the direct response function measurements.
Technical Paper

The Effects of Front Suspension Parameters on Road Wheel Toe Dynamics

2001-03-05
2001-01-0482
Front road wheel toe dynamics directly affects tire wear and steering wheel vibration, which in turn negatively impacts customer satisfaction. Though static toe can be preset in assembly plants, the front road wheels can vibrate around steering axes or kingpin axes due to tire mass unbalance and nonuniformity. The frequency of the vibration depends on the wheel size and vehicle speed, while the amplitude of the vibration is not only dictated by the tire forces, but also by suspension and steering parameters. This paper presents a study on the sensitivities of the front road wheel toe dynamics to the parameters of a short-long-arm suspension (SLA) and a parallelogram steering system. These parameters includes hard point shift, steering gear compliance, gear friction, control arm bushing rates, friction in control arm ball joints, and compliance in tie rod outboard joints.
Technical Paper

Spot Weld Failure Loads under Combined Mode Loading Conditions

2001-03-05
2001-01-0428
Failure loads of spot welds are investigated under static and impact loading conditions. A test fixture was designed and used to obtain maximum loads of spot welds under a range of combined opening and shear loads with different loading rates. Optical micrographs of the cross sections of spot welds before and after failure were obtained to understand the failure processes under various loading rates and different combinations of loads. The experimental results indicate that under nearly pure opening loads, the failure occurs along the nugget circumferential boundary. Under combined opening and shear loading conditions, the failure starts from the tensile side of the base metal near the nugget in a necking/shear failure mode. The effects of sheet thickness and combined load on the load carrying behavior of spot welds are investigated under static and impact loading conditions based on the experimental results.
Technical Paper

The Effect of High Mileage Spot Weld Degradation on Vehicle Body Joint Stiffness

2001-03-05
2001-01-0426
Joint stiffness is a major contributor to the vehicle body overall bending and torsional stiffness which in turn affects the vehicle NVH performance. Each joint consists of spot welds which function as load paths between adjacent sheet metal. Spot welds tend to lose structural integrity as a result of fatigue, loosening, aging, wear and corrosion of parts as a vehicle accumulates mileage. Experimental methods are used to identify potential degradation mechanisms associated with a spot weld. A CAE model which simulates a vehicle body joint generically is used to determine the effects of each individual degradation mode of a spot weld on joint stiffness. A real life B-pillar to roof joint CAE model of a production vehicle is then employed to examine the significance of weld distribution on joint stiffness degradation. The knowledge derived from this study can be used as a guidance in designing vehicle body structures with respect to spot weld distribution.
Technical Paper

Critical Engine Geometry Generation for Rapid Powertrain Concept Design Assessment

1998-02-23
981090
This paper presents some of the design rules used to calculate critical geometry of engine components, and the object-oriented component hierarchy system in PET. This paper also presents parametric solid model assembling schemes used to dynamically construct an assembly of whole powertrain systems. Some examples of powertrain concept design, such as the estimation of friction, packaging, and moving component clearances, will be presented. The computational efficiency of this concept design method will be compared to traditional methods also.
Technical Paper

Current and Past Technologies for Headliners Including Acoustics, Recycling and Safety

1998-02-23
980951
Headliner technology will be presented in this paper. Older established technologies such as cut & score, fiberglass, hardboard and resinated cotton are still used because of their proven reliability and low cost. But newer processes including polyester, natural fiber, Tramivex™ and urethane offer reliability, structure, acoustic performance and some recyclability. Fiberglass has always been a leader in acoustical performance but has breakage and handability issues in the assembly plants. This paper will be divided in four sections. The first section discusses manufacturing processes for headliners covering current and past. It also covers the materials used and types of facing. This section will state why headliner technology used in the USA is different than Europe or emerging markets. Second section describes acoustics. It will explain performance as related to material types. Porosity, cell type, fiber length and diameter is explained as it relates to the absorption of sound.
Technical Paper

Design and Development of 25% Post-Industrial Recycled SMC Hood Assembly for the 1998 Lincoln Continental Program

1998-02-23
981019
This paper describes the process of incorporation of 25% post-industrial recycled sheet molded composite (SMC) material in the 1998 Continental Hood inner. 1998 Continental Hood assembly consists of traditional SMC outer and this recycled hood inner along with three small steel reinforcements. BUDD Plastics collects SMC scraps from their manufacturing plants. The scrap is then processed and made into fillers for production of SMC. Strength of SMC comes from glass fibers and fillers are added to produce the final mix of raw materials. This recycled material is approximately 10% lighter and less stiff than the conventional virgin SMC. This presented unique challenges to the product development team to incorporate this material into a production vehicle in order to obtain the desired goal of reducing land fill and improving the environment.
Technical Paper

A Protocol for Testing and Evaluation of Paint Spray Applicators for the Automotive Industry

1998-09-29
982289
In this paper we discuss the development of a paint applicator system test protocol developed by Ford Motor Company. The test protocol involves spraying commercially available automotive primers, basecoats and clearcoats with known characteristics onto 90 cm long by 30 cm wide phosphated panels (36 in by 12 in) at application conditions necessary to obtain a typical range of film builds. The film builds are then measured at frequent intervals to obtain build averages, standard deviations, and spray pattern sizes. From these, transfer efficiency and pattern uniformity are obtained. In addition, the quality of the applied paint is measured at well defined film builds using several instruments to determine whether the application system being tested is capable of achieving the superb appearance demanded by our customers. Details of the required test matrix, the measurement templates and some comparative results obtained using the Ford protocol will be presented.
Technical Paper

An Experimental Investigation of Spray Transfer Processes in an Electrostatic Rotating Bell Applicator

1998-09-29
982290
A better understanding is needed of the electrostatic rotating bell (ESRB) application of metallic basecoat paint to automobile exteriors in order to exploit their high transfer efficiency without compromising the coating quality. This paper presents the initial results from experimental investigation of sprays from an ESRB which is designed to apply water-borne paint. Water was used as paint surrogate for simplicity. The atomization and transport regions of the spray were investigated using laser light sheet visualizations and phase Doppler particle analyzer (PDPA). The experiments were conducted at varying levels of the three important operating parameters: liquid flow rate, shaping-air flow rate, and bellcup rotational speed. The results show that bellcup speed dominates atomization, but liquid and shaping-air flow rate settings significantly influence the spray structure. The visualization images showed that the atomization occurs in ligament breakup regime.
Technical Paper

Engineering Moveable Glass Window Seals of Automotive Door Using Upfront CAE

1998-09-29
982383
The traditional moveable glass window seal development process has relied heavily on physical prototypes for design verification. Due to frequent styling changes and an overall reduction in design time, physical prototypes for the glass window seals have proven to be inadequate. Utilization of computer aided engineering (CAE) tools is necessary in order to shorten lead time. CAE tools will help to decrease expensive prototyping, free up valuable manufacturing line time, and improve overall quality. A cross functional approach has been applied to expand the scope beyond traditional methods of moveable glass window seal design, such as wedged boarding, into new computerized modeling methods. The CAE was used to address major requirements of the glass window seals including glass velocity, glass stall force, sealing-ability, seal durability, seal assembly, seal appearance, and regulator motor current.
Technical Paper

Paint Inspection Lighting

1998-09-29
982315
An improved defect detection system for painted surfaces has been developed which significantly increases topographic defect visibility (dirt-in-paint, sags/runs/drips, sealer-under-paint, spits, craters, etc.) for the final inspector / polisher. These minor defects can then be repaired before leaving the “spillout” deck. A new luminaire was designed to maximize the contribution of several applicable principles. The new process has significantly reduced the number of defects leaving the spillout area, doubled the number of “zero defect” vehicles, and increased energy savings from 25-40%. The improved Paint Inspection Lighting process was issued as a Uniform Process specification by the Ford Motor Company Vehicle Operations and was implemented in all of the Ford North American assembly plants.
Technical Paper

Laser & Fine Plasma Trimming of Sheet Metal Parts for Low Volume Production

1998-09-29
982333
This study compared laser and fine plasma technology for cutting typical electro-galvanized steel and aluminum automotive stampings. Comparisons were made of various aspects of cut quality, accuracy, disturbance of parent material, cycle time, and capital and operating costs. A sensitivity analysis was included to determine how different scenarios would impact the operating costs. It was found that both processes were capable of high quality cuts at 3800mm/min. Capital savings were achievable through the fine plasma system, but careful consideration of the specific application was essential. This work will allow for an advised comparison of options for sheet metal flexible cutting.
Technical Paper

Paint Bake Influence on AA7075 and AA7085

2017-03-28
2017-01-1265
The typical paint bake cycle includes multiple ramps and dwells of temperature through e-coat, paint, and clear coat with exposure equivalent to approximately 190°C for up to 60 minutes. 7xxx-series aluminum alloys are heat treatable, additional thermal exposure such as a paint bake cycle could alter the material properties. Therefore, this study investigates the response of three 7xxx-series aluminum alloys with respect to conductivity, hardness, and yield strength when exposed to three oven curing cycles of a typical automotive paint operation. The results have indicated that alloy composition and artificial aging practice influence the material response to the various paint bake cycles.
Technical Paper

Non-Linear Finite Element Analysis of Valve Seats and Valve Guides Assembly in Engine Cylinder Head

2017-03-28
2017-01-1090
In the shop floor, cracking issue was noticed during assembly of valve seat and valve guide in the engine cylinder head, especially near the valve seating area. This paper reveals a non- linear finite element methodology to verify the structural integrity of a cylinder head during valve seat and valve guide assembly press-in operation under the maximum material condition, i.e., smallest hole size on cylinder head for valve seat and guide and largest diameter of valve seat and guide. Material and geometrical nonlinearities, and contact are included in this method to replicate the actual seat and guide press-in operation which is being carried out in shop floor. The press-in force required for each valve seat and valve guide assembly is extracted from simulation results to find out the tonnage capacity of pressing machine for cylinder head assembly line. Stress and plastic deformation due to assembly load are the criteria checked against the respective material yield.
Technical Paper

Cylinder Head Design Process to Improve High Cycle Fatigue Performance

2017-03-28
2017-01-1074
Cylinder head design is a highly challenging task for modern engines, especially for the proliferation of boosted, gasoline direct injection engines (branded EcoBoost® engines by Ford Motor Company). The high power density of these engines results in higher cylinder firing pressures and higher operating temperatures throughout the engine. In addition to the high operating stresses, cylinder heads are normally heat treated to optimize their mechanical properties; residual stresses are generated during heat treatment, which can be detrimental for high-cycle fatigue performance. In this paper, a complete cylinder head high cycle fatigue CAE analysis procedure is demonstrated. First, the heat treatment process is simulated. The transient temperature histories during the quenching process are used to calculate the distribution of the residual stresses, followed by machining simulation, which results in a redistribution of stress.
Technical Paper

The Finite Element Analysis of Axle Nut Crimping

2017-03-28
2017-01-1323
In the assembly of axles and wheel hubs, a nut is frequently used to fasten them as one unit. In order for the nut to hold the assembly in its final position, crimping is a widely-used method which prevents nut from loosening. A reliable crimping process not only prevents movement of the nut during axle operation but should also minimize the possibility of cracking the rim. If the nut cracks during assembly, it can start to rust and deteriorate. The service life span of the axle assembly hence shortens as a result. The quality of crimping operation is determined by the component designs, the process parameters, and the crimping tool geometry. It would be time-consuming and costly to evaluate these factors empirically; let alone the requirement of prototypes in the early stage of a new program. A dynamic finite element methodology which adopts the Arbitrary Lagrangian-Eulerian formulation from ABAQUS explicit solver is developed to simulate the complete crimping process.
Technical Paper

Residual Effects of Metal Forming on Seat Belt Pull Analysis Results

2017-03-28
2017-01-1307
Automotive industries are emphasizing more and more on occupant safety these days, due to an increase in awareness and demand to achieve high safety standards. They are dependent on simulation tools to predict the performance of subsystems more accurately. The challenges being encountered are designs which are getting more complex and limitations in incorporating all real-life scenarios, such as to include all manufacturing considerations like forming and welding effects. Latest versions of solvers are slowly introducing new options to include these actual scenarios. Ls-Dyna is one of the explicit solvers to introduce these possibilities. The process of including stamping details into crash simulation is already being performed in the automotive industry. However, for seatbelt pull analysis, this has not been explored much.
Technical Paper

Use of Plastic Trim Fasteners for Automotive Trimming Applications

2017-03-28
2017-01-1304
For many years, the use of in-mold fasteners has been avoided for various reasons including: not fully understanding the load cases in the part, the fear of quality issues occurring, the need for servicing, or the lack of understanding the complexity of all failure modes. The most common solution has been the use of secondary operations to provide attachments, such as, screws, metal clips, heat staking, sonic welding or other methods which are ultimately a waste in the process and an increase in manufacturing costs. The purpose of this paper is to take the reader through the design process followed to design an in-molded attachment clip on plastic parts. The paper explores the design process for in-molded attachment clips beginning with a design concept idea, followed by basic concept testing using a desktop 3D printer, optimizing the design with physical tests and CAE analysis, and finally producing high resolution 3D prototypes for validation and tuning.
Technical Paper

Effective Application of CAE Guidance for Hemmed Closures Throughout the Vehicle Development Process

2017-03-28
2017-01-1310
The perceived quality of automotive closures (flushness and margin) is strongly affected by flanging and hemming of the outer panels and assembly respectively. To improve the quality of closures, the traditional hardware approach needs significant amount of time and costly die re-cuts and trials with prototype panels. Thus, such approach may delay the vehicle program and increase the overall investment cost. The proposed CAE methodology provides upfront design guidance to dies and panels, reduces time and increases cost savings associated with flanging and hemming while improving overall quality of the closures. In this proposed approach, as a first step, analytical formulae and design of experiments (DOE) are followed to estimate magnitude of design parameters of panels and dies as the upfront design guidance.
X