Learning Paradigm for Undergraduate-Virtual Design in Engineering Education




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Learning Paradigm for Undergraduate-Virtual Design in Engineering Education


1 Marija Gradinscak

Korea University of Technology and Education, Cheonan, Republic of Korea, m.gradinscak@kut.ac.kr


Abstract

Today many major companies and research institutes are using virtual technology. Therefore students need to be exposed to this technology if they are going to compete in a global world market. This newly developed Virtual Design course, allows students to visualize 3D objects, as realistically as possible, within the computer environment. This paper describes this new course, Virtual Design, offered for the first time to senior level students, by the School of Mechanical Engineering at the Korea University of Technology and Education. This Virtual Design subject focuses on design, problem-solving, presentation and communication skills. It is designed, using problem based learning, to provide students with experiences using a variety of CAD/CAE tools. However, the main objective of this course is to gain knowledge of parametric feature based modelling, analysing computer models using CFD and finite elements, as well as 3D visualization.


1. Introduction

Globalization is accelerating and with it, rapid technological change has resulted in the environment being dramatically impacted by constant and significant change. This constantly changing environment requires engineering education to be flexible and adaptable to the ever increasing demands of globalization. Hence we need to prepare our students for productive, creative and satisfying careers in the midst of rapidly increasing technological, social and political changes. Our students must be prepared for the global job market where the need for technically adept professionals who have the necessary skills to meet these new global trends and workplace demands. This requires universities to be educating their students for far more sophisticated jobs.


Computer simulation and virtual reality are at the forefront of scientific and engineering research and development, allowing us to create new knowledge. With advances in computer display technology, our students can experience and experiment with 3D objects as real objects of a mechanical design engineering project, within the computer environment. This capability of visualizing full-scale 3D models, has significantly improved the ability of students to comprehend and gain experience with reviewing design parameters and construction. This also allows students to better plan the design of complex models and explore their capabilities, which in the real world, results in a better product, produced in a shorter time, at a reduced cost. Truly addressing the authentic needs of the global market.


The emphasis of this course is on students gaining multidisciplinary knowledge of the parametric feature based modelling, Finite Element Analysis (FEA), Computational Fluid Dynamics (CFD) with the aim of enhancing the students 3D visualizations. This course is delivered to: encourage students’ interest in computer design engineering; as well as promoting the acquisition of the non-scientific skills required for the new global job market such as presentation skills, teamwork skills and management skills. We also strive to incorporate communicating effectively in the global corporate environment and being prepared for life-long learning.


This paper describes one of the initial efforts in developing curricula at KUT which integrates CAD and CAE into the virtual environment.


2. Background

The three-dimensional design world is becoming closer to reality with tools like the design process and virtual reality which are complimented by advancements in global communication, computers and multimedia devices. The approach encompasses the development of two dimensional form initially and then moves on to the three-dimensional design process model and then into an innovative proposal for a virtual reality model, [Oakes et al., 2006].


Virtual engineering is a user-centered process that provides a collaborative framework to integrate all of the models, data and decision-support tools needed for good engineering design. [Haque, 2005] acknowledged that with traditional teaching methods, focusing on lectures to deliver information, the complex analysis and design principles in structural design are almost impossible for students to understand. However if the theories are presented in a virtual environment, students’ conceptual understanding is enhanced dramatically.


[RHEINGOLD, 1991] defined virtual reality as an experience in which a person surrounded by a three dimensional computer-generated representation, is able to move around in the virtual world and see it from different angles, to reach into it, grab it, and reshape it. An emerging research field that seeks to transform the current engineering process is virtual engineering. The concept is to integrate a broad spectrum of engineering tasks into a virtual environment, [BRYDEN and McCORKLE, 2004].


[CHEN et al., 2006] indicated that the virtual reality approach helps the student in three dimensional visualisation, visualising abstract concepts, articulating their interpretation of phenomena, and visualising the dynamic relationships between several variables in a system.


[CECIL and HUBER, 2010] acknowledged the problem often overlooked is the lack of curriculum in undergraduate engineering programs that exposes students to Virtual Prototype techniques and technologies. While most mechanical, industrial and manufacturing engineering programs introduce their students to CAD/CAM technologies only a very limited number of institutions in the United States and worldwide have courses dealing with virtual prototyping and virtual engineering topics.


3. Method

3.1 Creating a Model for thVirtual Environment

Computer Aided Design (CAD)

To build a virtual environment, students need to build a 3D CAD model first. 3D modelling in parametric feature-based software begins with the constraint–based modelling with creation of a 2D sketch of the profile for the cross section of the part. Parametric sketching is an integral part of design and therefore was considered in detail in the beginning of lectures. Students start with a sketch definition using the sketcher application of SolidWorks. The sketch tools and concept of sketch planes and/or work planes are explained to students during lectures to assist in 3D construction of solid models. Understanding the concept of parametric modelling is crucial especially in the beginning, when parametric feature based software starts to be used. A simple example is: As the sketch planes are parametric, if the geometry moves, the sketch plane will move along with it. The next step is to constrain the 2D sketch by adding enough dimensions and relations to completely define the shape of the two dimensional profile.


In this stage students need to consider ‘design intent’ which is an important concept in parametric solid modelling design. Students need to know how to apply design intent in a sketch, a feature and a part, through dimensions, formulas and geometric constraints, students learn how to express the rules of the design intent and learn what is important and what ‘rules’ must be followed.


After completing the fully defined sketch, a three-dimensional object is created using boss/based features such as extruding and revolving to create a base feature-solid body. In this part students become familiar with solid modelling systems, which cover: feature based modelling and data associativity. In constraint based design, as a means of maintaining ‘design intent’, students were taught how to enforce rules or relationships on object geometry. All those constrained rules and relationships, students then need to apply in feature based modelling. For example, the centre point of a cylindrical boss feature may be constrained to remain concentric with the geometry of a base feature, so that if the geometry of the base feature is modified, the boss will be repositioned accordingly. Students get familiar with three types of constraints that can be applied whilst creating a sketch: numeric constraints, geometric constraints and algebraic constraints.


After acquiring the depth of knowledge required to create the base sketches, constraining the sketches and creating the base features, students continue with advanced modelling which includes applied features such as chamfers, fillets, shells and standardised hole features. Hole features are defined as packages of information that define features common to many components and are usually contained within ‘libraries’.


From the applied features, students continue with advanced 3D free-form geometry learning how to use complex spatial forms that, for example, can be found in the modern manufacturing and rapid prototyping applications as well as automotive and aeronautical designs.


In the 3D free form of surfacing modelling, students are introduced to theory and practice of NURBS curves and surfaces, their formulation, their implementation by CAD/CAM systems and the advantages of their use in geometric modelling. In advanced modelling students are exposed to the significance of NURBS and are introduced to the basics of surface modelling. Surface modelling in detail is covered with Advanced CAD course, newly developed at at KUT.


As the design intent requires a free change of size for various object features while keeping the topology constant, the students developed skills to work with constraints within the model as needed, to ensure that design intent is retained when the model is modified.


The curriculum is designed to provide students with experiences using a variety of CAD/CAM/CAE tools. Data associativity is the feature of a CAD system that permits design information to be passed to and from other applications, such as CAM and CAE. In the first four weeks students having acquired adequate knowledge of solid modelling, are then required to apply component parametric design to capture the design intent in relation to specific engineering constructions. As the component is a part of a product assembly all the geometry constructed needs to be parametrically defined and mutually related in relation to the design-functional requirements of the product, Figure1.




Fig. 1 Assembly model


Assembling parts is the final process of the 3D CAD model creation, Figure 2. Students in these lectures learned how to specify an assembly process using top down and bottom up methods. Designing the assembly of these parts demands a lot of decisions to be made during this design process. An important consideration during the process is the creation of the relationship between each component. Properly constrained assembly will be integrated later in motion analysis.




Fig. 2 Exploded assembly model-Steam Engine


Applying materials and rendering

After completing the parts and assembling these into the model, the next step is to apply materials and texture on this model. In this part of the process, students begin with predefined libraries which include metals, plastics, woods, glass, rubber, stones and many other textured material types. They also need to work with modified existing material properties, to work on reflection, transparency, roughness and texture-mapping.


Lighting is crucial in rendering, therefore placing lights in the scene to gauge the effect of these lights on the model, is essential. To gain complete control of the lighting in the scene, students had to experiment and investigate to develop their own way of applying lights in the space. Rendering enhances realism with advanced rendering options such as indirect illumination, caustics and global illumination; to adjust overall brightness and the reflections of scenes.


Finite Element Analysis (FEA) and Computational Fluid Dynamics (CFD)

Finite Element Analysis and Computational Fluid Dynamics are important parts of the Virtual environment, as they are replacing expensive physical prototyping, especially in the early conceptual design stage, when important decisions have to be made regarding fundamental product geometry, materials and manufacturing processes.


Computer software such as SolidWorks Simulation and Ansys are widely used software programs which perform a wide range of analysis and simulations. Such tools allow engineers to see how the product will behave and identify any errors early in the design cycle, thus optimising the design and reducing overall product development time and cost. Models created in CAD are the starting points for analysis. We use CAD models for describing geometric information for FEA. It is very important to understand how to prepare CAD geometry in order to produce correct FEA results and also to distinguish differences between the CAD model prepared for the FEA.


In the Virtual Design subject, students become familiar with FEA, Figure 3, and CFD which they use to determine stress, deformation, heat transfer, magnetic field distribution, fluid flow and other continuous field problems that would be impractical to solve using any other approach. During lectures students were introduced to the FEA steps using Solidworks as a starting point. They started with the pre-processing part of the FEA which includes: importing a solid model from CAD, building a mathematical model and then building the finite element model. The process of creating a mathematical model introduces the modification of CAD geometry, the definition of loads, restraints, material properties and the definition of the types of analysis. A properly discretised mathematical model to minimise discretisation errors, is an important part of pre-processing.


Solving the finite element model and post-processing of the results are other crucial parts in FEA software. In the building of the mathematical model, they learned how to prepare the geometry of the model. This part of this stage, is very important, as the selection of the mesh needs to provide the data of interest (stresses or temperature distribution) with acceptable accuracy. Proper interpretation of the results requires in-depth knowledge of the first three steps: defining the mathematical model, meshing and solving.


Verification of the results obtained from the computer simulations is extremely important. To validate their results from Solidworks, students had to use another software program. Ansys as another FEM package was chosen for verification.



Fig. 3 FEA in Design Simulation-Sustain Frame


Motion study

The motion studies include the development of animation and analysis of the assemblies. Solidworks motion environment is used to simulate and visualise the motion and performance of previously developed 3D models.


A basic animation is created using Animation Wizard from SolidWorks which gives the options of manipulating the final product in a virtual environment. The students also checked if the components of the product they built collided or interfered in the operation and if the product moved according to the design intent.

This Virtual Design process culminates in the ability to manipulate and explore the behaviour of the virtual product, as well as the ability to analyse the design process used, without physically creating a product. Additionally the ability to modify the required product if necessary, in a virtual environment, is advantageous and cost affective for manufacturing. This places our students at the forefront of engineering in this globalised world.


3.2 Teaching methodology

Traditionally the education of engineering students was delivered in universities through methods based on the dissemination of knowledge in lectures, which was later discussed and clarified in tutorials. Students were then expected to regurgitate this same information in examinations. Now so much more is demanded of graduate engineers and as a result of these increasing demands, universities are designing courses to equip their students for a far more complex, globalised world.


In the future, because of the tremendous advances in technology, engineers may be located in various countries across the world and be working on the same project. These projects are also becoming more complex, requiring lateral thinking and in depth understanding of the engineering process. Therefore graduate students need to be leaving universities with a deeper understanding of the complexities of the engineering process, requiring creativity, flexibility and lateral thinking. They will also need highly advanced communication skills to be able to communicate with colleagues across the world.


Universities across the world are now adopting engineering courses which address the need for these more sophisticated skills, with great success. These innovative courses place greater demands on students and a transitional model should be considered in the first instance, as this change can be quite confronting for students who have been used to being ‘spoon-fed’ and then have relied on their good memory and their ability to regurgitate information. This new style of education places greater demands on them to have deeper understandings of the engineering process and more advanced abilities to visualise their work and then communicate with colleagues/fellow students.


The Virtual Design course now being conducted at Korea university of Technology bridges the gap between the traditional courses once offered and the more innovative courses currently being trialled in other universities.


The Virtual Design course now being conducted at Korea university of Technology consists of 14 four-hour lessons lasting one semester. These weekly four hours are divided into 2 hours of lectures, being a traditional format and 2 hours of workshops. During these workshops students are encouraged/expected to use information gained in the lecture situation, but to also add to this by searching for their own additional information to support their projects.


After each lecture, two hours per week, the students are expected to work on assigned projects. The projects center on design problems. Among the lecture, students are encouraged to search for the additional information for the project. Being part of team the students learn how to communicate and co-operate solving major engineering problems. They learn how to professionally discuss different situations and problems. Each team member need to discuss his individual work and to be able to argument for his choice of solution. As a self learning approach, students also need to search for additional information, to read scientific papers, to search the Internet.


The project is the key element in curriculum applying the theoretical courses in problem solving and via the project being able to reflect on their professional work. Each week students need to discuss the progress of project to lecturer and lecturer guide them on the right track if necessary. Lecturer also read and discuss drafts for their documentation. It is worth to note that lecturer only guide them, not leading them to problem solution.


Team members are working together-discussing the project, design, simulations etc. Another important function of the team group is connected to learning process. During the development of solutions using virtual technology, some new knowledge has to be learned as well as existing knowledge is applied, which are directly related to the projects. The knowledge covers many academic subject disciplines in mechanical engineering. Similarly various skills are developed and practiced.


In the first four weeks students work on two individual projects- project related to the part and assembly design and power point presentation. This helped lecturer to test previous knowledge of the students in the field of CAD but also to decide for the degree of complexity of the problems for the team project.


In this context the effective communication extends beyond formal meetings and informal exchanges. Team members must be able to communicate the results of their work to each other in such a way that their work can be built upon by the other team members. Effective communication is the key to having successful global engineering operations.


The Virtual Design course consists of 14 four-four hour lessons lasting one semester. It addresses the feature-based component, product design specifically concentrating on form features and its relations to geometry, analysis and visual presentation of the final virtual model. As the ultimate educational goal of the Virtual Design course the students will excel in the team management through the practical application of engineering constructions.




Fig. 4 Students Virtual Design Second Project-Steam Engine


The example in Figures 4 illustrate the type of constructions as the result of a team project work. For the project work each team is required to propose an engineering design problem, which they have to manage and complete in the given timeframe of three weeks. Data organization, data flow and Engineering CAD design project in virtual environment are all applied through this project teamwork. The students are required to design a product and to prepare a final report demonstrating the management of an Engineering CAD design project.

4. Conclusion

Practising computer modelling and design using a virtual environment increases student learning. This type of Curricula which integrates the virtual reality environment helps to bridge the gap between industry-based projects and classroom case studies. This Virtual Design subject is one of the first applications exploring this technology at KUT and is only the beginning of a suite of models aimed at increasing students understanding of Mechanical Engineering concepts.


Student survey results indicate that the Virtual Design curriculum enables students to develop their spatial visualization ability, particularly for those who performed poorly previously using traditional engineering graphics methods. About 80% of the students indicated that the Virtual Design course had improved their spatial visualization abilities. Students gave Virtual Design very high ratings for stimulating their interest in engineering design.


References

BRYDEN, K. M. and McCORKLE, M.K., VESuite: A foundation for building virtual engineering models of high performance, low emission power plants, 29th International Technical Conference on Coal Utilization & Fuel Systems, Clearwater, FL, (2004).


CECIL, J. and HUBER, J., Virtual Prototyping in Engineering, Virtual Engineering, Momentum Press,(2010).


CHEN, C. J., The design, development and evaluation of a virtual reality based learning environment, Australasian Journal of Educational Technology, vol. 22, pp. 39-63, (2006).


G. L. OAKES, A. J. FELTON & D. HEESOML., The Virtual Reality Design Process Model: A Framework For Teaching Design Virtually, Design Principlesand Practices: An International Journal, Volume 3, pp. 467-478, (2006).


HAQUE, M.E., Web based visualization techniques for structural design education. Paper presented at the American society for Engineering Education conference, Paper Retrieved July 10, (2005), http://www.asee.org/conferences/search/01143_2001.pdf.


RHEINGOLD, H., Virtual Reality, Summit,New York, NY, (1991).

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