Browse
Recent Submissions
Item Implementation of Conformal Cooling & Topology Optimization in 3D Printed Stainless Steel Porous Structure Injection Molds(2016) Jahan, Suchana A.; Wu, Tong; Zhang, Yi; El-Mounayri, Hazim; Tovar, Andres; Zhang, Jing; Acheson, Douglas; Nalim, M. Razi; Guo, Xingye; Lee, Weng HohThis work presents implementation of numerical analysis and topology optimization techniques for redesigning traditional injection molding tools. Traditional injection molding tools have straight cooling channels, drilled into a solid body of the core and cavity. The cooling time constitutes a large portion of the total production cycle that needs to be reduced as much as possible in order to bring in a significant improvement in the overall business of injection molding industry. Incorporating conformal cooling channels in the traditional dies is a highly competent solution to lower the cooling time as well as improve the plastic part quality. In this paper, the thermal and mechanical behavior of cavity and core with conformal cooling channels are analyzed to find an optimum design for molding tools. The proposed design with conformal cooling channels provides a better alternative than traditional die designs with straight channels. This design is further optimized using thermo-mechanical topology optimization based on a multiscale approach for generating sound porous structures. The implemented topology optimization results in a light-weight yet highly effective die cavity and core. The reduction in weight achieved through the design of dies with porous structures is meant to facilitate the adoption of additive manufacturing for die making by the tooling industry.Item A Framework for Optimizing the Design of Injection Molds with Conformal Cooling for Additive Manufacturing(2015-01-01) Wu, Tong; Jahan, Suchana A.; Kumaar, Praveen; Tovar, Andres; El-Mounayri, Hazim; Zhang, Yi; Zhang, Jing; Acheson, Doug; Brand, Kim; Nalim, M. RaziThis work presents a framework for optimizing additive manufacturing of plastic injection molds. The proposed system consists of three modules, namely process and material modeling, multi-scale topology optimization, and experimental testing, calibration and validation. Advanced numerical simulation is implemented for a typical die with conformal cooling channels to predict cycle time, part quality and tooling life. A multi-scale thermo-mechanical topology optimization algorithm is being developed to minimize the die weight and enhance its thermal performance. The technique is implemented for simple shapes for validation before it is applied to dies with conformal cooling in future work. Finally, material modeling using simulation as well as design of experiments is underway for obtaining the material properties and their variations.Item Introduction: Special Section on Pressure Gain Combustion(American Institute of Aeronautics and Astronautics, 2017) Lu, Frank K.; Miller, Robert; Nalim, M. Razi; Yu, Kenneth H.; Mechanical Engineering, School of Engineering and TechnologyItem Project enhanced learning in challenging engineering courses(2012) Nalim, M. Razi; Li, Lingxi; Orono, Peter; Helfenbein, Robert; Yu, Whitney; Mital, ManuMany sophomores and juniors perform poorly in traditional lecture presentation of challenging engineering science courses, and this may present either a threat or opportunity for retention. Examples of such core ‘gateway’ courses in mechanical engineering and electrical engineering curricula include Thermodynamics, Signals and Systems, Probabilistic Methods, Statics, and Dynamics, among others. Test scores, surveys, and classroom assessments indicate that many students completing these courses did not really understand the fundamentals, even if they could apply the 'formulae’. A supplemental or alternative approach such as project-enhanced learning has been effective. The authors have implemented project experiences in three different courses, based on initial experience in a course on Thermodynamics. In Fall 2011, project-enhanced learning was introduced in two other courses: Probabilistic Methods In Electrical And Computer Engineering, and Dynamics in mechanical engineering. One or two major projects based on systems, objects, or activities that are familiar to the students are designed and assigned to apply key course topics. The goals are to motivate and improve learning of abstract concepts and to provide a realistic application that anchors and helps retain learning. Teamwork and professionalism were also emphasized. This paper will present the projects developed and the experience of the instructors in conducting the projects. Observed student reactions and learning will be discussed. Online discussion forums helped in project guidance and peer discussions. Each student team was required to submit a final project report at the end of the semester.Item Workshop: Project-Enhanced Learning in Engineering Science Education(2012) Nalim, M. Razi; Rajagopal, Manikanada; Helfenbein, RobertEarly drop out and poor retention rates are a major challenge to engineering education, which in many institutions have prompted a focus on improved first-year experiences. Retention and contributing learning challenges persists into the middle years, particularly when students confront the first engineering science courses in their major field. Students often perceive these courses as too abstract, intended to weed them out, and not meaningfully connected to their professional aspirations. A proven approach to improve student learning, self-efficacy, motivation, and retention is the use of active learning, including problems and projects. Despite evidence of the benefits of active learning, engineering schools and faculty members have inadequate incentives to experiment with non-traditional approaches.Item Project - Based learning in introductory thermodynamics(2009) Krishnan, Sivakumar; Nalim, M. RaziThe sophomore year is a critical decision point for engineering students. In freshman year, they might have been given exciting introductions to engineering design and applicable science by faculty dedicated to teaching. In sophomore year, they encounter traditional lecture presentation of challenging engineering science courses, probably by faculty more dedicated to research than undergraduate teaching. This may present either a threat or opportunity for retention of students. Introductory thermodynamics is usually such a 'gateway' course that must introduce to students both a new branch of science and an unfamiliar abstract method of scientific reasoning. Test scores, surveys, and classroom assessments indicate that many students did not really understand the laws of thermodynamics until the end of the course, if at all, even if they could apply the 'formulae'. A supplemental or alternative approach such as project-based learning may be very useful. This paper describes a design project in a mechanical engineering program at an urban research university. It was initially supplemental, but became a framework for alternative presentation of thermodynamics in a problem-based learning approach. The design project is intended to apply key topics in thermodynamics to a familiar domestic problem of heating, ventilation, and air conditioning (HVAC) system design for a residential application, based on manufacturer's specifications, second-law principles, and actual climate data. Students work in small teams of 2-3. The project is assigned and discussed at the beginning of the semester, so that it naturally motivates the learning of needed concepts throughout the semester. Teams were given annual climate data for different locations and defined home insulation, infiltration, and heat source properties. They were required to perform an energy audit and equipment thermodynamic performance evaluation to select specific units appropriate to the calculated heating and cooling loads. They recalibrate manufacturer ratings of the chosen units for local climate, and calculate the average cost of heating and cooling as well as the lifetime cost of the systems. This involved identifying the vendor and obtaining the necessary performance and cost data from them. Discussions were encouraged among the teams using an online discussion forum. Each student team was required to submit a final project report at the end of the semester and present their data. This project was implemented for a number of years by four different instructors. This holistic design and teamwork experience at the sophomore level appears to have given students a springboard benefit in the curriculum that persists into later courses and professional practice. Direct and indirect assessments of the project-based method were conducted and the results will be presented in the paper. The design project is assessed based on classroom presentations and a written report with technical analysis, design process, and professional conclusions. It is intended to continue restructuring the course syllabus around this project in the future.Item Faculty and Student Perceptions of Project-Enhanced Learning in Early Engineering Education: Barriers, Benefits, and Breakthroughs(2012) Nalim, M. Razi; Rajagopal, Manikanda K.; Helfenbein, Robert J.The application of problem-based learning (PBL) to undergraduate engineering education has emerged as an area of research interest over the past few decades. A related form of active learning is project-enhanced learning (PEL), intended to support integrative thinking and student motivation. PEL is specifically designed as a supplement to, but not a replacement for, traditional teaching methods in early engineering science courses. Data regarding perceived benefits and barriers to PEL as an intervention for improved student learning were collected from instructors engaged in PEL, and were examined using extended-term mixed-method research design (ETMM). ETMM enables researchers to remain attentive to contextual factors shaping program implementation and to changes in implementation over time. The case study included interviews with faculty, and survey instruments as part of the multiple data-point strategy. Among the findings, instructors adding PEL to their instructional strategies expressed satisfaction with improved student motivation, interaction, and socialization, which may help with student success and retention in engineering. Some instructors expressed concern about losing focus on the challenging analytical course topics, but those who attempted PEL were able to achieve appropriate balance by designing project tasks to align well with the topics and by limiting non-aligned project activity. In some cases, instructors who initially resisted adopting PEL changed to a favorable disposition after interacting with students and faculty who were favorable. However, a small number of instructors responded to the survey with a strong negative view of PEL.Item Hybrid Wave Rotor Electric Aero Propulsion(2014) Nalim, M. Razi; Bane, Sally P.M.; Khan, M. Javed; Jagannath, RavichandraPurpose: The goal of this project was to investigate the proposed hybrid wave-rotor electric aero-propulsion concept (HyWREAP). The tasks were to perform flow and combustion analysis of the pressure-gain, wave-rotor combustor (WRC) turbine concept, and investigate benefits for the most likely flight application of HyWREAP.Item Work in progress: Faculty perceptions of project-enhanced learning in early engineering education: Barriers and benefits(2012) Helfenbein, Robert J.; Nalim, M. Razi; Rajagopal, Manikanda K.The application of problem-based learning (PBL) to undergraduate engineering education has emerged as an area of research interest over the past few decades, although it does not appear to be the dominant pedagogy for most engineering programs. A related form of active learning is project-enhanced learning (PEL), specifically designed to enhance but not replace traditional teaching methods in engineering science courses. The perceptions of instructors who attempt PEL were examined using extended-term mixed-method approaches, seeking to examine perceived benefits and barriers to PEL as an intervention for improved student learning. Instructors expressed satisfaction with improved student motivation, interaction, and socialization, which may help with student success and retention in engineering. Instructors also expressed concern about losing focus on the challenging analytical course topics, but were able to achieve appropriate balance by designing project tasks to align well with the topics and limiting non-aligned project activity.Item Experimental Investigation on the Wave Rotor Constant Volume Combustor(AIAA, 2010-07-25) Matsutomi, Yu; Meyer, Scott; Wijeyakulasuriya, Sameera; Izzy, Zuhair; Nalim, M. Razi; Shimo, Masayoshi; Kowalkowski, Mike; Snyder, Philip; Mechanical Engineering, School of Engineering and TechnologyA wave rotor constant volume combustor was designed and built as a collaborative work of Rolls-Royce, Indiana University-Purdue University Indianapolis (IUPUI), and Purdue University. The experiment was designed to operate at rotational speeds of up to 4,200 rpm with air mass flow rates of approximately 18 lbm per second. Initial tests were conducted at 2,100 rpm with ethylene as fuel. The rig was operated with different fuel injection schemes to investigate operational characteristics of the combustor. Successful combustion and pressure gain were achieved over a range of operating conditions.