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Recently, there has been a new method for setting bearing preload on tapered roller bearings in a power transmission system. To move this new method into production, an analytical model that relates the bearing preload to the stiffness of the bearing was developed. This work develops an analytical model that links the preload on multi-row tapered roller bearings to the stiffness of the power transmission system. This study also validates the proposed analytical model by comparing it to both previous work and commercially available simulation software. The analytical model has shown that it is highly sensitive to the number of rollers in the bearing, which is discussed in this work.

Designing a centrifugal pump impeller comes with challenges due to multiple parameters that affect the pump efficiency. A high velocity gradient exists in the flow between the impeller shroud and sidewall of the pump casing due to one surface stationary and the other moving at a high velocity. The internal rotating flow in the impeller shroud-sidewall gap is a major problem that leads to a decrease in pump performance. This study presents a design modification of the gap between the impeller shroud and the pump casing sidewall using an idler disk located in between, which rotates freely during pump operation. In this paper, a numerical analysis was performed to investigate the idler disk's effect on the pump performance for different volumetric flow rate values and idler disk geometries. ANSYS-2019-R1 was used (FLUENT solver) to carry out the computational fluid dynamics (CFD) analysis for evaluating the performance of the baseline and modified designs in a centrifugal pump.

Enhancing the performance of centrifugal pumps requires a thorough understanding of the internal flow. Flow simulation inside the pump can help understand the rotatory motion induced by the impellers, as well as the flow instabilities. The flow inside a centrifugal pump is three dimensional, disturbed and accompanied by tributary flow structures. When a centrifugal pump operates under low flow rates, a secondary flow known as recirculation starts to begin. The separation of flow occurs which creates vortices and decreases local pressure which induces cavitation. This phenomenon of recirculation will rise the Net Positive Suction Head Required (NPSHR). This work aims to improve the pump efficiency under low flow rates by adding multiple cylindrical disks at the pump inlet section to suppress the flow recirculation. In this study, a numerical simulation is carried out to investigate the influence on the pump internal flow by adding multi cylindrical disks.

Formula SAE Collegiate Competition teams now regularly integrate aerodynamic body kits with their vehicles which have significant benefits in producing downforce. This use of body kits (or aero packages) and the improvement to vehicle aerodynamics they provide, have resulted in these systems becoming a necessity for any team wishing to remain competitive in Formula SAE (FSAE). To address this the Lawrence Technological University (LTU) Formula SAE team incorporated an aerodynamic body kit into their 2018 vehicle. Using computational fluid dynamics (CFD) an aerodynamic analysis was performed comparing the efficacy of a car that did not have an aero package to a car that did. Two separate simulation programs were employed to effectively and accurately assess this change. By using both SolidWorks and SimScale software to generate data, the results of each were compared to assess the accuracy of each.

This paper presents methods of rapid prototyping design and manufacturing used in the development of a centrifugal pump impeller with curved spacer (CS). In this research subtractive and additive rapid manufacturing methods were applied to create complex curved spacer profiles for testing as part of geometry optimization process for a high speed and high flow rate centrifugal pump impeller. Seven models for the curved spacer were designed and each model was integrated with the bare impeller separately for simulation analysis. One design was selected for manufacturing with applying subtractive and additive processes. In subtractive manufacturing method, the raw material was removed from a solid shaft by a cutting process under digital control from a computer file. The complexity of the modified impeller spacer profiles required the use of expensive CNC machining with five axis capability.

AASHTO I-Beam is a standard structural concrete part for bridge sections. The flexural performance of an AASHTO I-Beam is critical for bridge design. This paper presents an application of Digital Image Correlation (DIC) Method in full-scale AASHTO I-Beam flexural performance study. A full-scale AASHTO I-Beam pre-stressed with steel strands is tested by three-point bending method. The full-scale AASHTO I-Beam is first loaded from 0 kips to 100 kips and is then released from 100 kips to 0 kips. A dual-camera 3D Digital Image Correlation (DIC) system is used to measure the deflection and strain distribution during the testing. From the DIC results, the micro-crack generation progress during the loading progress can be observed clearly from the measured DIC strain map. To enable such a large-scale DIC measurement, the used DIC setup is optimized in terms of the optical imaging system and speckle pattern size.

A vehicle’s exterior fit and finish, in general, is the first system to attract customers. Automotive exterior engineers were motivated in the past few years to increase their focus on how to optimize the vehicle’s exterior panels split lines quality and how to minimize variation in fit and finish addressing customer and market required quality standards. The design engineering’s focus is to control the deviation from nominal build objective and minimize it. The fitting process follows an optimization model with the exterior panel’s location and orientation factors as independent variables. This research focuses on addressing the source of variation “contributed factors” that will impact the quality of the fit and finish. These critical factors could be resulted from the design process, product process, or an assembly process. An empirical analysis will be used to minimize the fit and finish deviation.

This paper presents an experimental investigation of flow field instabilities in a centrifugal pump impeller at low flow rates. The measurements of pump hydraulic performance and flow field in the impeller passages were made with a hydraulic test rig. Analysis of Q-ΔP-η data and flow structures in the impeller passages were performed. In the present work, the effect of various flowrates on centrifugal pump impeller performance was analyzed based on pump measured parameters. The impeller’s geometry was modified, with positioning the curved spacer at the impeller suction side. This research investigates the effect of each inlet curved spacer model on pump performance improvement. The hydraulic performance and cavitation performance of the pump have been tested experimentally. The flow field inside a centrifugal pump is known to be fully turbulent, three dimensional and unsteady with recirculation flows and separation at its inlet and exit.

Cooling fans have many applications in industrial and electronic fields that remove heat away from the system. The process of designing a new cooling fan with optimal performance and reduced acoustic sources can be fairly lengthy and expensive. The use of CFD with support of mesh morphing, along with the development of optimization techniques, can improve the acoustic’s performance of the fan model. This paper presents a new promising method which will support the design process of a new cooling fan with improved performance and less acoustic surface power generation. The CFD analysis is focused on reducing the acoustic surface power of a given cooling fan’s blade using the surface dipole acoustic power as the objective function, which leads to an optimized prototype design for a better performance. The Mesh Morpher Optimizer (MMO) in ANSYS Fluent is used in combination with a Simplex model of the broadband acoustic modeling.

Today's strict fuel economy requirement produces the need for the cars to have really optimized shapes among other characteristics as optimized cooling packages, reduced weight, to name a few. With the advances in automotive technology, tight global oil resources, lightweight automotive design process becomes a problem deserving important consideration. It is not however always clear how to modify the shape of the exterior of a car in order to minimize its aerodynamic resistance. Air motion is complex and operates differently at different weather conditions. Air motion around a vehicle has been studied quite exhaustively, but due to immense complex nature of air flow, which differs with different velocity, the nature of air, direction of flow et cetera, there is no complete study of aerodynamic analysis for a car. Something always can be done to further optimize the air flow around a car body.

Thermal management systems (TMS) of armored ground vehicle designs are often incapable of sustained heat rejection during high tractive effort conditions and ambient conditions. During these conditions, which mainly consist of high torque low speed operations, gear oil temperatures can rise over the allowable 275°F limit in less than twenty minutes. This work outlines an approach to temporarily store excess heat generated by the differential during high tractive effort situations through the use of a passive Phase Change Material (PCM) retrofit thereby extending the operating time, reducing temperature transients, and limiting overheating. A numerical heat transfer model has been developed based on a conceptual vehicle differential TMS. The model predicts the differential fluid temperature response with and without a PCM retrofit. The developed model captures the physics of the phase change processes to predict the transient heat absorption and rejection processes.

Bearings are a major component in any rotating system. With continually increasing speeds, bearing failure modes take new unconventional forms that often are not understood. In high speed applications, rolling element forces and gyroscopic moments can be significantly high compared to the applied forces acting on a bearing. Such moments create a “driving” torque causing outer race to creep. In this paper a mathematical model for the dynamics of a rolling element in a high speed bearing is derived. Preload values counterbalancing the torque driving the outer race to rotate can be predicted from this model. An attempt to experimentally measure this torque using a specially designed apparatus with integrated strain gauge torque sensor is also described. Both model and experimental measurements are aimed at understanding, and therefore preventing bearing failures due to outer race (creep) rotations.

The American Axle & Manufacturing Inc. driveline dynamometer provides immense value for experimental validation of product NVH performances. It has been intensively used to evaluate product design robustness in terms of build variations, mileage accumulation, and temperature sensitivity. The current driveline dynamometer input motor system has multiple torsional modes which create strong coupling with test part gear mesh dynamics. Mechanical Engineering seniors at Lawrence Technological University designed, fabricated, and validated a mechanism to decouple the driveline dynamics from the driveline dynamometer dynamics. The student-designed decoupler mechanism is presented with experimental validation of effectiveness in decoupling driveline dynamometer dynamics from the driveline under test.

The experimental methods focused on utilizing the newly developed NOVA induction heating and hardening manufacturing process as an adapted method to produce high performance engine valve springs. A detailed testing plan was used to evaluate the expected and theorized possibility for fatigue life enhancement. An industry standard statistical analysis method and tools were employed to objectively substantiate the findings. Fatigue cycle testing using NOVA induction-hardened racing valve springs made of ultra-high tensile material were compared to data for springs with traditional heat treatment and those with standard processing. The results were displayed using Wöhler and modified Haigh fatigue life diagrams. The final analysis suggests that NOVA processed springs have a seemingly slight, yet significant benefit in fatigue life of 5 - 7% over springs processed through a competing method.

A new inter-disciplinary degree program has been developed at Lawrence Technological University: the Master of Science in Mechatronic Systems Engineering Degree (MS/MSE). It is one of a few MS-programs in mechatronics in the U.S.A. today. This inter-disciplinary program reflects the main areas of ground vehicle mechatronic systems and robotics. This paper presents areas of scientific and technological principles which the Mechanical Engineering, Electrical and Computer Engineering, and Math and Computer Science Departments bring to Mechatronic Systems Engineering and the new degree program. New foundations that make the basis for the program are discussed. One of the biggest challenges was developing foundations for mechanical engineering in mechatronic systems design and teaching them to engineers who have different professional backgrounds. The authors first developed new approaches and principles to designing mechanical subsystems as components of mechatronic systems.

To stay competitive, new products require faster development time at low cost and good quality. Defense as well as commercial industries are forced to use analytical tools to stay competitive in a tough market. The use of simulation tools and approximation techniques in evaluating product performance during the early stages of the product development has a major impart on the product development efficiency, effectiveness, and lead time. Building physical prototypes of complex systems is expensive and it is difficult and time consuming to develop them. It is extremely beneficial to know as much as possible about the product performance and to optimize its dynamic characteristics before the first physical prototype is built.

The reliability of engine valve springs is a very important issue from the point of view of warranty. This paper presents a combined experimental and statistical analysis for predicting the fatigue limit of high tensile engine valve spring material in the presence of non-metallic inclusions. Experimentally, Fatigue tests will be performed on valve springs of high strength material at different stress amplitudes. A model developed by Murakami and Endo, which is based on the fracture mechanics approach, Extreme value statistics (GUMBEL Distribution) and Weibull Distribution will be utilized for predicting the fatigue limit and the maximum inclusion size from field failures. The two approaches, experimental and theoretical, will assist in developing the S-N curve for high tensile valve spring material in the presence of non-metallic inclusions.

All-wheel drive (AWD) vehicle performance considerably depends not only on total power amount needed for the vehicle motion in the given road/off-road conditions but also on the total power distribution among the drive wheels. In turn, this distribution is largely determined by the driveline system and its mechanisms installed in power dividing units. They are interwheel, interaxle reduction gears, and transfer cases. The paper presents analytical methods to evaluate the energy and, accordingly, fuel efficiency of vehicles with any arbitrary number of the drive wheels. The methods are based on vehicle power balance equations analysis and give formulas that functionally link the wheel circumferential forces with slip coefficients and other forces acting onto an AWD vehicle. The proposed methods take into consideration operational modes of vehicles that are tractive mode, load transportation, or a combination of both.

A low cost fault tolerant and redundant multiplex wiring system specifically designed for automotive applications is described in this paper. Although there are many multiplex wiring systems are being used to simplify the car wiring harness, but very few are low cost, fault tolerant and redundant at the same time. Most of the system address mainly the protocol and software issues and neglected the reliability of the multiplex wiring system. This paper addresses the fault tolerant and redundancy of the system and use hardware based integrated circuit to convert from parallel to serial at the transmitter side and serial to parallel at the receiver side.

The airflow through a standard automotive throttle body is not exactly proportional to the displacement of the accelerator pedal. Therefore, another method is needed to open the butterfly valve in order to ensure that airflow through the throttle body is metered equal to pedal displacement. This paper finds that the implementation of a cam-type pulley is necessary to achieve this prescribed goal.