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Modal Expansion using Strain Mode Shapes
No full textReduction/expansion approaches have been conventionally used in correlation and validation studies. Recently, these approaches have also been used to extract full-filed results on structures using limited set of data measured. The expansion techniques are used to expand real-time data measured on components of vehicle chassis, utility scale wind turbines, and helicopter rotors. The resulted full-field data is used to monitor structures and determine their durability. With the advances in Digital Image Correlation (DIC), researchers are able to readily extract strain mode shapes of structures. However, the conventional reduction/expansion techniques are usually limited to displacement, velocity, or acceleration data. This can hinder correlation studies that compare the strain data between two models. Furthermore, this limitation does not allow researchers to expand strain-gage measured data for full-field structural monitoring and durability analysis. / In the current paper, a reduction/expansion technique has been developed to reduce/expand strain data. In this technique, measured strain at limited locations is expanded using strain mode shapes to extract full-field results on the entire surface and within the structure. This technique can also be used to reduce data for correlation studies. In order to demonstrate the merit of the approach, the proposed strain expansion approach was applied to the finite element model of a cantilever beam subjected to sinusoidal and impact excitations. The results show that the proposed approach can effectively expand the strain measured at limited locations. The approach could accurately predict the strain at locations where no sensors were placed
... and Dr. Diane Peters
No full text... and Dr. Diane Peters peer into an autonomous vehicle (prototype?) at the SAE World Congress 2017.https://digitalcommons.kettering.edu/autodrive_gallery/1002/thumbnail.jp
Paul Smith Talks to Kettering President McMahan About the University\u27s Work with Autonomous Vehicles
No full textInterview between host Paul W. Smith and Kettering University President Robert McMahan about the AutoDrive Challenge. Recorded May 8, 2017.https://digitalcommons.kettering.edu/autodrive_pubs/1000/thumbnail.jp
AutoDrive Section A Small Group Team Picture September 20th, 2017
No full textThis is an Autodrive team picture taken on Wednesday September 20th, 2017 for A section, containing a small group of the teams, sub-teams, faculty, and staff.https://digitalcommons.kettering.edu/autodrive_gallery/1006/thumbnail.jp
Mixed model multi-manned assembly line balancing problem: a mathematical model and a simulated annealing approach
No full textPurpose – This paper aims to study a generalized type of mixed-model assembly line with multi-manned workstations where multiple workers simultaneously perform different tasks on the same product. This special kind of assembly line is usually utilized to assemble different models of large products, such as buses and trucks, on the same production line. Design/methodology/approach – To solve the mixed-model multi-manned assembly line balancing problem optimally, a new mixed-integer-programming (MIP) model is presented. The proposed MIP model is nondeterministic polynomial-time (NP)-hard, and as a result, a simulated annealing (SA) algorithm is developed to find the optimal or near-optimal solution in a small amount of computation time. Findings – The performance of the proposed algorithm is examined for several test problems in terms of solution quality and running time. The experimental results show that the proposed algorithm has a satisfactory performance from computational time efficiency and solution accuracy. Originality/value – This research is the very first study that minimizes the number of workers and workstations simultaneously, with a higher priority set for the number of workers, in a mixed-model multi-manned assembly line setting using a novel MIP model and an SA algorithm
Temporal Variation in Ankle Fractures and Orthopedic Resident Program Planning in an Urban Level 1 Trauma Center
No full textPrevious studies have described the mechanism of ankle fractures, their seasonal variation, and fracture patterns but never in conjunction. In addition, the cohorts previously studied were either not from trauma centers or were often dominated by low-energy mechanisms. The present study aimed to describe the epidemiology of ankle fractures presenting to an urban level 1 trauma center. The records from an urban level 1 trauma center located in the Midwestern United States were retrospectively reviewed, and the injury mechanism and energy, time of injury, day of week, month, and patient characteristics (age, gender, comorbidities, smoking status) were collected. The fractures were classified using the AO (Arbeitsgemeinschaft für Osteosynthesefragen), Lauge-Hansen, and Danis-Weber systems. Of these systems, the Lauge-Hansen classification system resulted in the greatest number of “unclassifiable” cases. Most ankle fractures were due to high-energy mechanisms, with motor vehicle collisions the most common high-energy mechanism. The review found that most ankle fractures were malleolar fractures, regardless of the mechanism of injury. The ankle fracture patients had greater rates of obesity, diabetes, and smoking than present in the region where the hospital is located. The fractures were most likely to occur in the afternoon, with more fractures presenting on the weekend than earlier in the week and more fractures in the fall and winter than in the spring and summer. The temporal variation of these fractures should be considered for health services planning, in particular, in regard to resident physician staffing at urban level 1 trauma centers
Effects of Boundary Conditions and Inflation Pressure on the Natural Frequencies and 3D Mode Shapes of a Tire
No full textTires are one of the major sources of noise and vibration in vehicles. The vibration characteristic of a tire depends on its resonant frequencies and mode shapes. Hence, it is desirable to study how different parameters affect the characteristics of tires. In the current paper, experimental modal tests are performed on a tire in free-free and fixed conditions. To obtain the mode shapes and the natural frequencies, the tire is excited using a mechanical shaker and the response of the tire to the excitation is measured using three roving tri-axial accelerometers. The mode shapes and resonant frequencies of the tire are extracted using LMS PolyMax modal analysis. The obtained mode shapes in the two configurations are compared using Modal Assurance Criterion (MAC) to show how mode shapes of tires change when the tire is moved from a free-free configuration to a fixed configuration. It is shown that some modes of the tire are more sensitive to boundary conditions. Furthermore, the effects of inflation pressures on the resonant frequencies and mode shapes of the tire are studied by varying the pressure of the tire and measuring the change in modes of the tire
Breakdown of synthetic-clay-filled nanocomposite polypropylene
No full textA study on the breakdown of polypropylene filled with synthetic nano-clay is presented. The synthetic clay contents were 0 %, 2 %, 4% and 6 % by weight in host polypropylene. After preparing each specimen a power-frequency, sinusoidal voltage was applied to the specimen with a well-defined ramp-rate up to a level at which a breakdown occurred. The breakdown voltage of the specimen was considered as the measured rms voltage at the breakdown. The mean breakdown strength seems to improve about 13.5% for the nanocomposite with 2% synthetic clay as compared to the plain polypropylene. Although improvements were observed on the breakdown strength of nanocomposites with higher contents of synthetic clay the improvement was not as dramatic as was the case between the 0% and 2% contents in polypropylene. Thus, it can be concluded that the nanocomposite with 2% synthetic clay content is the optimum. Moreover, an overall improvement was determined on the breakdown strength of the nanocomposites with the increase of the voltage ramp-rate
Unveiling of the Chevy Volt 01
No full textThis is at an AutoDrive unveiling event on October 30, 2017. Pictured is the Chevy Volt car covered in a blue tarp.https://digitalcommons.kettering.edu/autodrive_gallery/1009/thumbnail.jp
Reduced Graphene Oxide on Nickel Foam for Supercapacitor Electrodes
Get PDFThe focus of this paper is the investigation of reduced graphene oxide (GO)/nickel foam (RGON) samples for use as supercapacitor electrodes. Nickel foam samples were soaked in a GO suspension and dried before being subjected to two different methods to remove oxygen. Atmospheric pressure annealed (APA) samples were treated with a varying number (10–18) of nitrogen plasma jet scans, where sample temperatures did not exceed 280 °C. Furnace annealed (FA) samples were processed in an atmosphere of hydrogen and argon, at temperatures ranging from 600 °C to 900 °C. Environmental Scanning Electron Microscope (ESEM) data indicated that the carbon to oxygen (C:O) ratio for APA samples was minimized at an intermediate number of plasma scans. Fourier Transform Infrared Spectroscopic (FTIR) and Raman spectroscopic data supported this finding. ESEM analysis from FA samples showed that with increasing temperatures of annealing, GO is transformed to reduced graphene oxide (RGO), with C:O ratios exceeding 35:1. X-ray Photoelectron Spectroscopy (XPS) and X-ray diffraction (XRD) data indicated the formation of RGO with an increasing annealing temperature until 800 °C, when oxygen reincorporation in the surface atomic layers becomes an issue. Supercapacitors, constructed using the FA samples, demonstrated performances that correlated with surface atomic layer optimization of the C:O ratio