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Technical Paper

A New Multi-point Active Drawbead Forming Die: Model Development for Process Optimization

1998-02-01
980076
A new press/die system for restraining force control has been developed in order to facilitate an increased level of process control in sheet metal forming. The press features a built-in system for controlling drawbead penetration in real time. The die has local force transducers built into the draw radius of the lower tooling. These sensors are designed to give process information useful for the drawbead control. This paper focuses on developing models of the drawbead actuators and the die shoulder sensors. The actuator model is useful for developing optimal control methods. The sensor characterization is necessary in order to develop a relationship between the raw sensor outputs and a definitive process characteristic such as drawbead restraining force (DBRF). Closed loop control of local specific punch force is demonstrated using the die shoulder sensor and a PID controller developed off-line with the actuator model.
Technical Paper

Machinability of As-Compacted P/M Parts: Effect of Material Chemistry

1998-02-23
980635
Since the advent of P/M technology as a near net shape production process, millions of mechanical components of various shapes and sizes have been produced. Although P/M continues to be one of the fast growing shaping processes, it suffers from the inability to produce intricate geometry's such as internal tapers, threads or recesses perpendicular to pressing direction. In such cases application of machining as a secondary forming operation becomes the preferred alternative. However, machining of P/M parts due to their inherent porosity is known to decrease tool life and increase tool chatter and vibration. Consequently, several attempts have been made to improve the machinability of P/M materials by either addition of machinability enhancing elements such as sulfur, calcium, tellurium, selenium, etc., or by resin impregnation of P/M parts.
Technical Paper

Blend Ratio Optimization of Fuels Containing Gasoline Blendstock, Ethanol, and Higher Alcohols (C3-C6): Part I - Methodology and Scenario Definition

2013-04-08
2013-01-1144
The U.S. Renewable Fuel Standard (RFS2) requires an increase in the use of advanced biofuels up to 36 billion gallons by 2022. Longer chain alcohols, in addition to cellulosic ethanol and synthetic biofuels, could be used to meet this demand while adhering to the RFS2 corn-based ethanol limitation. Higher carbon number alcohols can be utilized to improve the energy content, knock resistance, and/or petroleum displacement of gasoline-alcohol blends compared to traditional ethanol blends such as E10 while maintaining desired and regulated fuel properties. Part I of this paper focuses on the development of scenarios by which to compare higher alcohol fuel blends to traditional ethanol blends. It also details the implementation of fuel property prediction methods adapted from literature. Possible combinations of eight alcohols mixed with a gasoline blendstock were calculated and the properties of the theoretical fuel blends were predicted.
Technical Paper

Preparation and Characterization of Nanophase Gold Catalysts for Emissions Control

2008-10-07
2008-01-2639
Various gold catalysts were prepared using commercial and in-house fabricated advanced catalyst supports that included mesoporous silica, mesoporous alumina, sol-gel alumina, and transition metal oxides. Gold nanoparticles were loaded on the supports by co-precipitation, deposition-precipitation, ion exchange and surface functionalization techniques. The average gold particle size was ∼20nm or less. The oxidation activity of the prepared catalysts was studied using carbon monoxide and light hydrocarbons (ethylene, propylene and propane) in presence of water and CO2 and the results are presented.
Technical Paper

Design for 6 Sigma Application in Engine System Integration

2015-09-29
2015-01-2864
With stringent emission regulations, many subsystems that abate engine tailpipe-out emissions become a necessary part for engines. The increased level of complexity poses technical challenges for the quality and reliability for modern engines. Among the spectrum of quality control methodologies, one conventional methodology focuses on every component's quality to ensure that the accumulative deviation is within predetermined limits. This conventional methodology tightens the component tolerance during the manufacturing process and typically results in increased cost. Another conventional methodology that is on the other side of the spectrum focuses on tailoring an engine calibration solution to offset the manufacturing differences. Although the tailored engine calibration solution reduces manufacturing cost for components, it increases the development and validation cost for engines. Given the cost and time constraints, system integration plays an important role in engine development.
Technical Paper

Numerical Simulation of Unsteady Natural Convection in a Simplified Engine Bay Enclosure under Soak Conditions

2014-04-01
2014-01-0651
At the onset of soak, air and surface temperatures in an engine bay enclosure are elevated since temperature of heat sources are high while convective cooling is sharply reduced as a result of airflow being shut off from the inlet grilles of the vehicle leading to temperature spikes. Accurate simulation of this important thermal and flow regime that is natural convection driven, highly transient and complex is therefore very important. In this investigation, we simulate flow in the engine bay at the onset of soak with fixed thermal boundary conditions where the geometries representing the engine bay and components are simplified. Good agreement was observed with detailed experimental data available in references for both velocities and temperatures.
Technical Paper

Caterpillar’s Autonomous Journey - The Argument for Autonomy

2016-09-27
2016-01-8005
Today’s business climate and economy demand new, innovative strategies from the initial kickoff of research and development - to the mining of ore from the earth - to the final inspection of a finished product in a mid-western factory. From startup companies with two employees to the largest companies, the world faces new and challenging requirements every day. The demands from companies, customers, executives, and shareholders continue to drive for higher outputs with more efficient use of personnel and investments. Fortunately, the rate of technology continues to exponentially accelerate, which allows those at the cutting edge of technology to capitalize. Caterpillar has been a pioneer in advanced technology since its inception and has been developing the foundation for autonomy over the past four decades.
Technical Paper

Initiating a Values Based Culture at Track-Type Tractors Division of Caterpillar Inc.

1999-03-01
1999-01-0250
During the early 1990s, the Track-Type Tractors Division (TTTD) of Caterpillar Inc. experienced several challenges. The Division faced increasing global competition in the midst of an economic recession. Although intense plant modernization and reorganization occurred in the five previous years, the business unit was not profitable. In 1993, Track-Type Tractors Division instituted its solution -- a change in its culture. Previously, the culture hindered the division’s ability to move forward. This was revealed in a 1992 review detailing the major obstacles inhibiting management from achieving divisional goals. The division leaders recognized that a change in business philosophy, as opposed to further plant modernization, was required to achieve production goals and stay globally competitive.
Technical Paper

Prediction and Measurement of Microstructure and Residual Stresses due to Electron Beam Welding Process

1999-04-14
1999-01-1872
Electron beam (EB) welding process is characterized by an extremely high power density that is capable of producing weld seams which are considerably deeper than width. Unlike other welding process, heat of EB welding is provided by the kinetic energy of electrons. This paper presents a computational model for the numerical prediction of microstructure and residual stress resulting from EB welding process. Energy input is modeled as a step function within the fusion zone. The predicted values from finite element simulation of the EB welding process agree well with the experimentally measured values. The present model is used to study an axial weld failure problem.
Technical Paper

Characterization of the Three Phase Catalytic Wet Oxidation Process in the International Space Station (ISS) Water Processor Assembly

2000-07-10
2000-01-2252
A three phase catalytic mathematical model was developed for analysis and optimization of the volatile reactor assembly (VRA) used on International Space Station (ISS) Water Processor. The Langmuir-Hinshelwood Hougen-Watson (L-H) expression was used to describe the surface reaction rate. Small column experiments were used to determine the L-H rate parameters. The test components used in the experiments were acetic acid, acetone, ethanol, 1-propanol, 2-propanol and propionic acid. These compounds are the most prevalent ones found in the influent to the VRA reactor. The VRA model was able to predict performance of small column data and experimental data from the VRA flight experiment.
Technical Paper

Direct Bonding of a Multi-Layer Circuit Substrate to a Heatsink

2007-10-30
2007-01-4220
Phoenix International, the electronics manufacturing group of John Deere, has developed a product and manufacturing process to address many of the shortcomings of conventional heatsinking technologies. In this process, a thin circuit board is bonded directly to a flat surface heatsink such as a finned extrusion or liquid-cooled plate. The major benefits of the proposed solution are the simplification of the manufacturing process and substantially improved conduction of heat away from high-power circuitry.
Technical Paper

Induction Hardening Simulation of Steel and Cast Iron Components

2002-03-19
2002-01-1557
The induction hardening process involves a complex interaction of electromagnetic heating, rapid cooling, metallurgical phase transformations, and mechanical behavior. Many factors including induction coil design, power, frequency, scanning velocity, workpiece geometry, material chemistry, and quench severity determine a process outcome. This paper demonstrates an effective application of a numerical analysis tool for understanding of induction hardening. First, an overview of the Caterpillar induction simulation tool is briefly discussed. Then, several important features of the model development are examined. Finally, two examples illustrating the use of the computer simulation tool for solving induction-hardening problems related to cracking and distortion are presented. These examples demonstrate the tool's ability to simulate changes in process parameters and latitude of modeling steel or cast iron.
Technical Paper

Reduction of the Environmental Impact of Essential Manufacturing Processes

1999-03-01
1999-01-0355
The drive of Design for the Environment is to reduce the environmental impact of both design and manufacturing processes. The most frequent method recommended is to substitute better materials and processes. However, there are processes that will continue to have undesirable environmental impacts due to the lack of knowledge of better methods. These processes are critical to manufacturing of products and can not be eliminated. All possible substitutions appear to have worse impacts. This paper explores modeling these processes and imposing a control method which permits an improvement of the environmental impact.
Technical Paper

Pressure-Swirl Atomization in the Near Field

1999-03-01
1999-01-0496
To model sprays from pressure-swirl atomizers, the connection between the injector and the downstream spray must be considered. A new model for pressure-swirl atomizers is presented which assumes little knowledge of the internal details of the injector, but instead uses available observations of external spray characteristics. First, a correlation for the exit velocity at the injector exit is used to define the liquid film thickness. Next, the film must be modeled as it becomes a thin, liquid sheet and breaks up, forming ligaments and droplets. A linearized instability analysis of the breakup of a viscous, liquid sheet is used as part of the spray boundary condition. The spray angle is estimated from spray photographs and patternator data. A mass averaged spray angle is calculated from the patternator data and used in some of the calculations.
Technical Paper

FD&E Total Life T-Sample Residual Stress Analytical Predictions and Measured Results

2019-04-02
2019-01-0528
The SAE Fatigue Design & Evaluation Committee is actively working on a total life project for weldments, in which the welding residual stress is a key contributor to an accurate assessment of fatigue life. Physics-based welding process simulation and various types of residual stress measurement were pursued to provide a sufficiently accurate representation of the residual stress field at the failure location in the fatigue samples. A well-controlled and documented robotic welding process was used for all sample fabrication to provide accurate inputs for the welding simulations. Both destructive (contour method, x-ray diffraction (XRD) with etching) and non-destructive (surface XRD, energy dispersive diffraction (EDD), neutron diffraction(ND)) residual stress measurements were performed on the same or similarly welded samples. The sample is constructed with multiple-pass fillet welds, which induce large gradients in residual stress through the one-inch thickness.
Journal Article

Standardization of Graphics for Service Information and Translation Expense Reduction

2009-10-06
2009-01-2857
The cost of human natural language translation of Service Information, Assembly Instructions, Training Materials, Operator Manuals and other similar documents is a major expense for manufacturers. One translation avoidance method involves replacing most of a document’s text with still and/or animated graphics. While the graphics with minimum text concept has savings potential, clarity of communication must be maintained for widespread application of this technique. The necessary clarity should be achieved if standards are established for the symbols and graphical conventions used. This paper provides an example of a repair procedure documented using the graphics with minimum text paradigm, describes many of the anticipated standards and provides an update on the progress towards achieving a standard development project.
Technical Paper

Comparison of Total Fatigue Life Predictions of Welded and Machined A36 Steel T-Joints

2019-04-02
2019-01-0527
A new total fatigue life methodology was utilized to make fatigue life predictions, where total fatigue life is defined as crack initiation and subsequent crack propagation to a crack of known size or the component’s inability to carry load. Fatigue life predictions of an A36 steel T-joint geometry were calculated using the same total fatigue life methodology for both welded and machined test specimens that have the same geometry. The only significant difference between the two analyses was the inclusion of the measured weld residual stresses in the welded specimen life predictions. Constant amplitude tests at several load levels and R ratios were analyzed along with block cycle and variable amplitude loading tests. The accuracy of the life predictions relative to experimental test lives was excellent, with most within a factor of +/- two.
Technical Paper

Testing of Welded and Machined A36 Steel T-Joint Configuration Specimens

2019-04-02
2019-01-0535
For this latest SAE Fatigue Design and Evaluation project, fatigue tests were run by loading, in bending, both welded and machined T-Joint specimens that have the same geometry. The test rig setup consisted of a horizontally mounted actuator, with pinned joints at both ends, where the load is applied to the top of the vertical leg of the “upside down T” of a T-Joint specimen, while the horizontal legs of the “upside down T” were clamped to the bedplate. Specimens were tested until failure or until the specimen was unable to carry the commanded load. They were cycled under constant amplitude (at several load levels and R ratios), block cycle, and variable amplitude loadings. Welded and machined T-Joint specimens of the same geometry were included in the test plan such that fatigue life predictions could be compared to test lives for each case. Those comparisons would demonstrate the methodology’s relative predictive ability to manage welds, residual stress, etc...
Technical Paper

Numerical Prediction and Verification of Noise Radiation Characteristics of Diesel Engine Block

2019-06-05
2019-01-1591
To assess contribution of structure-borne noise from the engine, it is critical to characterize dynamic and vibro-acoustic properties of the engine components and assembly. In this paper, a component level study of a three-cylinder diesel engine block is presented. Virtual analysis was done to predict natural frequencies and mode shapes of the engine block at the first step. Then, these results were used to decide the optimum test location and an experimental modal test was conducted on the engine block. The initial virtual model was correlated with test using natural frequencies and mode shapes. Then, the virtual model was updated with damping derived from experimental modal test to match vibration frequency response functions. Further, the virtual model was used for prediction of vibro-acoustic transfer functions. The vibro-acoustic transfer functions were also obtained from test. The results of transfer function were correlated with test.
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