Showing papers by "Stephen Ekwaro-Osire published in 2006"

Effect of Attachment Configuration on Impact Vibration Absorbers

Abstract: This experimental research deals with passive vibration control of a primary mass using an impact vibration absorber (IVA). This paper is on two types of IVAs, namely, a simple IVA and a compound IVA, which have different attachment configurations for the impacting mass. The main contribution of this work was to experimentally analyze the effect of attachment configuration on IVAs. Thus, the primary objective of this research was to compare the absorption characteristics of simple and compound IVAs in case of transient and forced vibration. The secondary objective was to determine the effect of system parameters on the absorption efficiency of a compound IVA for both transient and forced vibration. It was shown that, for forced vibrations, the simple IVA (compared to the compound IVA) has more pronounced inefficient absorption region. On the other hand, the compound IVA hardly has a clear inefficient absorption region. In the respective absorption region, it is noted that the simple IVA has a more prominent vibration absorption level. Practical applications of the results are also discussed.

Impact of Selection of Projects on Pan-Mentoring in Creative Engineering Design

Abstract: Pan-mentoring, a pedagogical approach to creative engineering design education, establishes a close relationship between the pan-mentor and a design team of students as well as among the individuals within the team. This paper focuses on the impact of the selection (and screening) of design projects on pan-mentoring in creative engineering design. The selected projects should, among others, have good prospects for successful completion, stimulate creativity, and be challenging. This paper will analyze four sources of design projects, namely, faculty projects, industry supported projects, student initiated projects, and projects for design competitions. A project-screening scheme will be discussed. An assessment will be performed on the student selection process. Additional data will be provided to show the impact of the project selection on the students' perception on the design activity. It will also be shown that a well selected project and the application of the pan-mentoring pedagogy can enhance engineering design education and help to prepare students for a fast changing future. This study was performed at two universities.

Effect of Reference Loading and Crack Configuration on the Stress Intensity Factors In Weight Function Method

Abstract: In calculating the stress intensity factors (SIFs) using the weight function method, the accuracy of the result depends upon proper selection of the set of reference loadings. The objective of the present work is to find a unique set of reference loadings to calculate the SIF at the tip of a crack of any configuration. Additionally, the universality of these reference loadings with respect to calculating the SIF for various crack configurations is examined. Two sets of crack configurations were considered, with and without a pre-existing crack. In each set, a horizontal crack and a slanted crack were analyzed.

Probabilistic Analysis of MEMS Asymmetric Gear Tooth

Abstract: Asymmetric gear teeth are used to improve the performance of gears by increasing the load capacity or by reducing vibrations. Recently these types of gears have found application in MEMS devices where the use of gears is on the rise. In this research a probabilistic computer program, in conjunction with a commercially available finite element program, is developed and the reliability of the asymmetric gear tooth is studied. Specifically, the probability of failure of the asymmetric gear is extracted for various parameters. The parameters considered included pressure angle, tooth height, and contact ratio. The efficacy of using asymmetric gear tooth is shown in this study.Copyright © 2006 by ASME

Developing An Assessment Regime For Pan Mentoring In Creative Engineering Design

Abstract: Pan-mentoring (from the Greek pan meaning all, to indicate a mentoring relationship with a team of students) is a pedagogical approach to creative engineering design education establishing a close relationship with and within design teams of students. The role of the pan-mentor consists of: helping students to effectively tap into their creativity as individuals and as teams; guiding them through the design process at both the individual and team level; and encouraging selfreflection and assessment. This paper develops and discusses an assessment regime for the three elements of pan-mentoring in creative engineering design. In the regime, student assessment, course assessment, and pan-mentor assessment are utilized. In this paper, the only data discussed is from a questionnaire (course assessment) completed by freshmen students. The results from this part of the assessment regime were favorable.

Modified Weibull Failure Theory for Size Effect Prediction of Brittle Thin Film

Abstract: A brittle thin film bonded to a substrate is common in MEMS components. At the edge of the interface, high stress gradients exist. It has been observed that mechanical strengthening of the thin film with decreasing film size occurs due to two constraints, namely, the microstructural constraint and the geometrical constraint. Consideration of both these constraints is required to properly predict the size effect impact on the strength of a brittle thin film. In this paper, a statistical approach is developed to predict the size effect of a brittle thin film on a substrate.Copyright © 2006 by ASME