Tom Eppes

Implementation of a Remote Analog and Digital Communications Laboratory for e-Learning

Rapid changes in the field of engineering technology have increased the need for universities to provide engineering and engineering technology students with meaningful and relevant practical experiences; however, limited available resources in the provision of laboratory hardware and infrastructure have been the principal impediment in achieving this objective. Such hardware limitations have been increasingly marginalizing the quality of engineering and engineering technology education. E-learning can be used to help universities and technical colleges overcome this problem. One approach that can be implemented to overcome this problem is to expand e-learning activities in programs with limited resources to take advantage of online computer-based technology. In this model, remote instrumentation technology and the internet are merged to interface students with the physical world

Laser percussion drilling modeling utility

Laser percussion drilling is widely used in the aerospace industry to produce cooling holes in jet engine components. A variety of theoretical models have been developed to predict the outcome of the drilling process. However, to utilize these models often requires sophisticated software to perform the required numerical analyses. A simple and easy-to-use computer utility Drilling Routine for Estimating, Analyzing, and Modeling (DREAM) was developed. DREAM is a free-standing MATLAB-based design that offers a convenient and flexible way to predict a variety of drilling process outcomes and can be executed on any Windows-based platform. This paper discusses the features that have been incorporated into the latest release.

Multiphysics modeling with high priority research applications

Baccalaureate engineering graduates are facing an emerging class of design challenges that span multiple disciplines of science and technology. Sophisticated computational techniques, combining the representative physics of multiple domains, are needed to accurately model and predict results. Many engineering degree programs offer major specific modeling courses or embed simulations on a limited basis. For example, mechanical undergraduates may be exposed to solid modeling and computational fluid dynamics while electrical majors apply finite element techniques to electromagnetic problems. Few engineering curricula offer multiphysics design and research experiences. Where available, they are typically restricted to post-graduate studies; consequently, most baccalaureate graduates receive little or no exposure to areas of expertise outside of their discipline. This is inconsistent with the view that future graduates need to be more adaptable and versatile to succeed in a knowledge-based global marketplace.

Optical inspection of holes in jet engine blades

The need for improved thermal efficiency of jet engines has led to changes in the design of combustor turbine blades. Modern turbine stage inlet temperatures now exceed the melting point temperatures of turbine blade materials. Super alloys, based on nickel, have been developed for use as blades, guide vanes, afterburners etc. To combat and avert blade failure caused by excessive operating temperatures, film cooling has been incorporated into blade design. In film cooling, cool air is bled from the compressor stage, ducted into internal chambers of the turbine blades, and discharged through small holes in the blade walls. This provides a thin, cool, insulating blanket along the external surface of the turbine blade, and large numbers of shaped holes have allowed designers to maximize the cooling effect. This paper explores a new design for measuring the presence and depth of blind holes in turbine blade. In the paper, we examine the inspection techniques currently in use and present a novel optical technique as an alternative. To precisely locate and measure the holes on the turbine blade, an XYZ translation stage is employed. Using a small collimating tube, a micro-beam illuminates each hole in a pre-programmed fashion. Depending on the level of reflected intensity and when it occurs, the presence of a hole bottom is determined. The optical inspection system consists of a laser, motorized micro-positioning stage, collimating tube, optical detector/amplifier, data acquisition software and a customized fixture for manipulating the samples.

Noncontact vibration analysis using innovative laser-based methodology

Vibration is a back and forth mechanical motion with a steady, uninterrupted rhythm about an equilibrium point. There are two types of vibration; natural (or free) and forced. Natural vibration occurs as the result of a disturbing force that is applied once and then removed. Forced vibration occurs as a result of a force applied repeatedly to a system. All machines have some amount of forced vibration. However, in some cases this vibration can cause damage to machinery. Understanding vibration is essential for any system that will be exposed to motion. Equipment such as strain gauges and piezoelectric accelerometers have been adequate in measuring vibration in the past; however, due to increased performance requirements and subsequent reductions in vibration, these methods are slowly being replaced by laserbased measurement systems. One reason for the slow transition is that part of the system in these methods must be mounted on the surface of the object being measured which can change the mass thus alter the frequency and mode shape of the vibrating object. At this time however, the high expenses to monitor precision vibration is a challenge, and there is a need for more cost-effective methods of vibration analysis. This paper outlines a lower cost laser-based method of measuring vibration with minimum surface contact.

Achieving and sustaining gender balance in an undergraduate teaching institution

Recruiting and retaining women in the STEM faculty ranks has been a national priority for many years. Recent research, sponsored by the NSF ADVANCE program, was performed mostly by doctoral institutions. However, for small undergraduate universities, the resulting challenges and decision frameworks are likely to be different. The prevalent recommendations need to be re-evaluated and re-interpreted for relevance and applicability. Multiple change agents have been identified, but it is believed that the departmental climate most strongly correlates with successful institutional transformation. The primary success factor is a set of formalized processes in: (1) teaching, scholarship and service, (2) mentoring, and (3) leadership. A secondary factor is a faculty support infrastructure capable of fostering collaborations and reducing isolation. A third factor is an introspective capability that broadens the understanding of the issues affecting women ultimately expressed in the form of better policies and procedures. There is a strong connection between gender progress on the faculty side and improving the pipeline of female students. To effectively intervene on the supply side, it is important to have networking, mentoring and role modeling processes that match student demographics and global sociological conditions. In the case of our University, this requires recruiting, developing and retaining faculty whose principal focus is undergraduate education which is challenging in STEM fields where the traditional emphasis is on research. Curricular evolution in doctoral institutions is typically driven by emerging trends and technological opportunities while the needs of regional industries and local programs are more influential among primarily undergraduate institutions. As advanced degrees become a professional requirement, baccalaureate graduates will be expected to pursue advanced studies early in their career. Hence, more undergraduate STEM programs will serve as feeders to doctoral institutions. The future supply of graduate students and ultimately faculty will become more dependent on these teaching universities. This paper describes our specific efforts and successes in the context of an undergraduate teaching institution. We have demonstrated that even with limited resources and no external funding, it is possible to improve the community culture and climate. Tangible strategies and initiatives aimed at improving the climate are presented: (1) administrative leadership commitment, (2) grants and endowments, (3) faculty development resources, (4) workshops that mirror industry successes, (5) early and mid-career planning, and (6) recruiting and retention of female faculty.

Application building in engineering courses

This paper discusses how application building has been integrated into a set of graduate and undergraduate engineering courses that contain computational simulation learning outcomes. Applications (apps) were first included in a multidisciplinary modeling graduate course that culminates in the end-of-semester research effort. At the undergraduate level, apps were added into a two-course mechanical engineering thermo-fluids sequence. Since introducing apps, students have become demonstrably more engaged in the subject matter and are devoting more time out of the classroom to understand fundamental concepts. Simulations have long been used to analyze and predict performance in order to guide engineering design teams. Now, commercial software suppliers have bundled application building into their offerings. An effective app has a simplified interface yet it contains the full efficacy of the underlying model without exposing the end user to its complexity. Within the modeling software, COMSOL Multiphysics®, an Application Builder allows developers to quickly create easy-to-use apps based on working models. The finished app provides for the inputs, settings, and outputs the user is allowed to control and view. Companies as well as research organizations are using apps to extend product models to their constituents, be it customers, supply chain members or the broader scientific community. Leveraging simulation models accompanied by apps is proving to be an efficient way to add an additional skillset to our graduates as they enter the workplace. The paper provides an overview of how application building is employed at the engineering graduate and undergraduate levels. Examples of modeling and simulations assigned in the aforementioned courses are discussed. Illustrations of student work as well as the assessment criteria used to measure performance are presented.

New Approach to the Inspection of Cooling Holes in Aero-Engines

The need for improved thermal efficiency of jet engines has led to changes in the design of combustor turbine blades. Modern turbine stage inlet temperatures now exceed the melting point temperatures of turbine blade materials. Super alloys, based on nickel, have been developed for use as blades, guide vanes, afterburners etc. To combat and avert blade failure caused by excessive operating temperatures, film cooling has been incorporated into blade design. In film cooling, cool air is bled from the compressor stage, ducted into internal chambers of the turbine blades, and discharged through small holes in the blade walls. This provides a thin, cool, insulating blanket along the external surface of the turbine blade. Large numbers of shaped holes have allowed designers to maximize the cooling effect. This paper explores a new design for inspecting turbine blade cooling holes. We examine the inspection techniques currently in use and present a novel optical technique as an alternative. Our design consists of two stages of inspection, each optically based. The first stage uses a camera positioned axially in line with a laser beam. A sample is mounted on an XY micro-positioning stage, and a vision system captures an image of the sample and displays the size and shape of each entrance hole. To measure the presence of a bottom, a second XYZ inspection stage is used. Using a small collimating tube, a micro-beam illuminates a drilled hole in a pre-programmed fashion.

Modeling utility for percussion laser drilling – Experiment vs theory

Laser percussion drilling is widely used in the aerospace industry to produce cooling holes in jet engine components. A variety of theoretical models have been developed to predict the outcome of the drilling process. However, to utilize these models often requires sophisticated software to perform the required numerical analyses. We developed a simple and easy- to-use computer utility called DREAM (Drilling Routine for Estimating, Analyzing and Modeling). DREAM is a free-standing, MATLAB-based design that offers a convenient and flexible way to predict a variety of drilling process outcomes and can be executed on any Windows-based personal computer. This paper discusses new features that have been incorporated into the 2007 Beta release.Laser percussion drilling is widely used in the aerospace industry to produce cooling holes in jet engine components. A variety of theoretical models have been developed to predict the outcome of the drilling process. However, to utilize these models often requires sophisticated software to perform the required numerical analyses. We developed a simple and easy- to-use computer utility called DREAM (Drilling Routine for Estimating, Analyzing and Modeling). DREAM is a free-standing, MATLAB-based design that offers a convenient and flexible way to predict a variety of drilling process outcomes and can be executed on any Windows-based personal computer. This paper discusses new features that have been incorporated into the 2007 Beta release.

Optimization of parameters for effective welding of aerospace components

This paper reports research results in two areas. First, it defines laser-welding processes for jet engine turbine components and specifies the steps and parameters for that process. Secondly, it proposes an optimization routine aimed at finding optimum welding procedures and parameters since laser welding is not commonly used in aerospace applications. This paper proposes guidelines for laser welding of nickel-alloy sheet metal up to 0.061” in thickness. These guidelines are based in part on processes previously reported in the literature including comparisons with conventional welding technologies.One area where laser welding may prove advantageous is in improving the cost and quality of combustor component manufacturing (Figure 1). The results of a feasibility study of laser welding including quality, material integrity, and economic benefits are included. Recommendations in the area of design guidelines to maximize the benefits of laser welding in the manufacturing process are provided.This paper reports on the use of a fiber laser for welding using three control factors: optical power, welding speed and minimum spot diameter for an Inconel 625 sheet. Using a Taguchi design of experiment model, laser weld outcomes are analyzed and optimal weld porosity results are reported.This paper reports research results in two areas. First, it defines laser-welding processes for jet engine turbine components and specifies the steps and parameters for that process. Secondly, it proposes an optimization routine aimed at finding optimum welding procedures and parameters since laser welding is not commonly used in aerospace applications. This paper proposes guidelines for laser welding of nickel-alloy sheet metal up to 0.061” in thickness. These guidelines are based in part on processes previously reported in the literature including comparisons with conventional welding technologies.One area where laser welding may prove advantageous is in improving the cost and quality of combustor component manufacturing (Figure 1). The results of a feasibility study of laser welding including quality, material integrity, and economic benefits are included. Recommendations in the area of design guidelines to maximize the benefits of laser welding in the manufacturing process are provided.This paper repo...