MRI/RUI Acquisition of a Portable Large Scale Visualization System for Nondestructive Evaluation 3. Project Description

Transcription

1 MRI/RUI Acquisition of a Portable Large Scale Visualization System for Nondestructive Evaluation 3. Project Description (a) Results from Prior NSF Support Grant in Progress: CMS , NSF-MRI, Development of a Configurable Thermal Imaging System for Nondestructive Evaluation of Materials, $91,935, October 1, 2000 September 30, (PI: John C. Chen Co-PI: Shreekanth A. Mandayam). The objective of this project is to develop a thermal imaging system to detect mechanical damage in gas pipelines. This system will augment existing magnetic imaging systems that are currently employed for detecting corrosion damage in pipelines. Status: The CCD imaging system has been developed, test specimens have been fabricated and we are currently in the process of gathering data. Results from this research activity will be presented at the annual Review of Progress in Quantitative Nondestructive Evaluation, scheduled to be held in Bellingham, WA, in July Grant in Progress: DUE , NSF CCLI, Hands on the Human Body, $162,326, March 1, 2001 February 29, 2004 (PI: Stephanie Farrell, Co PIs: Anthony J. Marchese, Jennifer A. Kadlowec, John L. Schmalzel, Shreekanth A. Mandayam, Senior Personnel: Paris Von Lockette, Edward C. Chaloupka). The goal of this project is to engage students in the scientific discovery process via exploration of the engineering systems within the human body using hands-on reverse engineering methods. Status: Instructional modules have been developed for the Freshman Engineering Clinic II course and will be implemented during the course of the Spring 2002 semester. Results from this activity will be disseminated at the annual ASEE Conference and Exposition to be held in Montreal, Canada in June Grant in Progress: DUE , NSF-CCLI, Communications, Signal Processing and VLSI: Education Under a Common Framework, $74,939, March 1, 2001 February 28, 2003 (PI: Ravi P. Ramachandran, Co-PIs: John L. Schmalzel, Linda M. Head, Shreekanth A. Mandayam, Steven H. Chin). The goals of this project are to configure novel methods

2 of combining the laboratory content of the following three Junior-II courses Electrical Communications Systems, Digital Signal Processing and VLSI Design. Status: Laboratory manuals have been developed and are being implemented in the Spring 2002 offering of these courses. Results from this activity will be disseminated at the annual ASEE Conference and Exposition to be held in Montreal, Canada in June 2002.

3 (b) Research Activities Motivation and background Nondestructive evaluation (NDE) continues remain a significant engineering enterprise that is essential for assuring the integrity of a variety of large-, medium- and small-scale infrastructure in the United States today. The increase in the number of aging aircraft in our civilian fleet, deteriorating bridges and roadways (especially on the East coast) that are essential for maintaining our transportation needs, have contributed to a concerted effort by funding agencies, academia and industry to devise more reliable techniques for in-line nondestructive inspection. In the wake of recent terrorist attacks, concerns have been expressed regarding the security and safety of nuclear power plants and oil and natural gas pipelines key contributors towards maintaining the nation s energy supply. The NDE research and development community has continually exploited the ongoing advances in telecommunications, micro- and nano-electronics, instrumentation, computational methods, software development, etc. to better serve the needs of their constituents. This proposal seeks support for developing methods to augment this technology growth in NDE with a field that has seen a rapid evolution in recent years virtual reality. Virtual Reality (VR) (Bryson 1993, Ellis 1994) is a synergistic combination of cutting-edge computation, visualization and display technologies that simulates an immersive environment, in which a user can interact with a dynamic, computer generated environment. VR systems allow the user to intuitively create, perceive, experience and explore a virtual environment that appears sufficiently real. The relationship between the participant and the virtual environment can be defined using a conceptual VR model, based on a concrete understanding of human perceptual systems (Gibson 1986). Although VR systems can take a variety of forms, a typical implementation consists of the following three elements (a) immersion, (b) navigation, and (c) interaction, as shown in Figure 1 (Krueger 1992). Immersion represents the degree of audio-visual and sensory stimulation that is offered to the participant it is a function of the level of user interaction, type of display, the dimension, proximity and intimacy of the viewing environment, image frame rate, model complexity, sound and sensory (touch) effects.

4 Immersion Techniques Wireframe Surface modeling Texture mapping VR Navigation Translation Rotation Scaling Interaction Mouse Head Mounted Displays Data Gloves Figure 1: Elements of VR. Navigation refers to the ability of the user to explore the cyberspace; typical techniques that are employed include object translation, rotation and scaling. Interaction allows the user to manipulate the virtual environment and thus enhance the virtual experience. Recent advances in computer technology have had a significant impact on the quality and cost of VR technology. Commercially available systems range from room-sized synthetic environments (CAVEs) to desktop manifestations, offering limited, but sufficient levels of immersion. There are two situations in which the application of VR techniques can play significant roles in improving the NDE process: (a) Defect characterization of NDE signals (b) Virtual prototyping of NDE systems A description each of these applications are provided below. In each case, specific examples of research projects in the Rowan NDE laboratory are provided. Defect characterization of NDE signals Defect characterization mechanisms prevalent in the industry range from calibration based approaches to simple parametric methods to sophisticated techniques using

5 artificial neural networks. A complete signal characterization system provides the following capabilities: (a) signal classification this isolates defect signatures from signals obtained due to benign changes in geometry. (b) signal location this is used to provide a precise location of the flaw with respect to specimen geometry (c) flaw profiling this provides a 3-dimensional geometrical description of the flaw that can be used by subsequent visualization stages. A key requirement in modern NDE environments is the desire to reduce inspection turnaround time this places enormous demands on the data analyst. Reviewing and digesting large amounts of data before deciding appropriate remediation measures generates stressful conditions that can prove ultimately detrimental to the inspection procedure. Data presentation plays a vital role in managing large volumes of both raw and processed NDE data. With modest effort, current VR tools can be effectively exploited to provide: (a) Simultaneous display of NDE signals from multiple modalities and reconstructed flaw profiles in the infrastructure (b) Navigation though the infrastructure (c) System response to user requests. Objects displayed in the VR environment are classified as either static or dynamic. Static objects are those whose shapes remain unaltered and they correspond to the infrastructure in a defect-free state. These objects are generated using existing CAD drawings of the structural part. The NDE signals and the predicted defect profiles are dynamic objects, since their shapes reflect changing data conditions. The navigation system allows the user to steer through a virtual world that is populated by various static and dynamic objects. The environment also allows the generation of a printable log that provides a concise list of the location and size of defects along with an indication of severity. The display environment could consist of a conventional monitor, a 3-D screen projection (requiring special glasses) or a head mounted unit. Tactile responses can use conventional mouse driven point-and-click signaling or employ sophisticated haptic

6 sensors. The virtual environment integrates the knowledge of existing CAD drawings of the structural part with information generated by the data fusion and signal characterization system. Successful adaptation of existing VR technology will provide the data analyst with a powerful tool for assimilating information without overload. Figure 2 shows a block diagram of an NDE system for natural gas pipeline inspection, augmented with VR tools (Mandayam 1995, Mandayam 1996). One of the current research projects in the NDE laboratory at Rowan requires developing techniques for inline inspection of natural gas pipelines using magnetic and thermal techniques. The objective of this project is to develop a thermal imaging system to detect mechanical damage in gas pipelines. This system will augment existing magnetic imaging systems that are currently employed for detecting corrosion damage in pipelines. Current technology involves the use of an in-line inspection vehicle called a pig that is propelled inside of a pipe under the pressure of natural gas. The thermal sensors will be in the form of a configurable array of infrared CCD cameras, which will permit the complete imaging of the pipeline as the pig travels its length. The goal is to arrive at a minimal modification of the current inspection tool design, making the system attractive to pipeline-inspection vendors. The addition of a thermal-imaging sensor to the existing magnetic sensor offers the opportunity for fusing the two data sets in order to improve the accuracy and sensitivity of the inspection tool. Virtual prototyping of NDE systems VR technology can have significant impact on the design of NDE systems. VR provides the opportunity to perform virtual NDE simulating NDE processes from conceptual design through service. This technique is also referred as virtual prototyping and has been pioneered by the automobile and aircraft manufacturing industry. Following extensive deployment of VR tools in the design of the newer cars and airplanes, this type of simulation has gained a strong foothold as being part of the engineering design process. Figure 3 shows a typical concurrent engineering design cycle in which VR technology is not used. Concurrent engineering refers to a paradigm in which time and effort is spent on developing a production process, even at the initial stages of the design; and all steps

7 Test object Thermal Imaging (Passive Monitoring) Event triggered Magnetic Flux Leakage (Active Monitoring) Signal Pre-Processing Data Fusion Signal Characterization CAD User VR Module (Visualization) Remaining Life Prediction Fracture Mechanics Models Expert System Suggestions for Remediation 3-D Reconstruction Figure 2: Application of VR for defect characterization in the NDE of gas pipelines.

8 in the design process are continually evaluated and updated. In such a system, after identifying a product/system need, Concept n, out of a total of N proposed concepts, is taken through the entire design cycle from initial design calculation to final production. The Go No Go decisions for each proposed concept occur early on in the design cycle issues of project cost and time dictate this approach. Incorporation of VR technology into the concurrent engineering design cycle allows this threshold to be placed strategically, thus providing significant savings in personnel and process costs. The following two scenarios are possible: (a) (Figure 4) Concept n proceeds though the complete design cycle, but all of the other concepts include a virtual prototyping stage after which they are each accepted or rejected. The virtual prototyping facility allows the design team to explore each competing concept comprehensively, before making a final design decision. This method also allows the team to easily resurrect old concepts that were discarded earlier, if they later show promise. (b) (Not illustrated) The VR engine can provide a visual interface to every stage of the design process identifying resources/modifications required and streamlining procedures. Such a design process is called Virtual Engineering. It can be a powerful method to explore parts of the design process that are difficult to incorporate in an educational environment; for example, manufacturing. An example of a current R&D project in the NDE laboratory that can be significantly enhanced with the application of virtual prototyping is a magnetic imaging system being developed for a local HD-TV manufacturer. The objective of this project is to design, develop and test a system for acquiring and displaying the magnetic flux density vector in 3-D space inside a HD-TV internal magnetic shield. This project will provide the sponsor with a PC-controlled, semi-automated test facility for a minimally invasive interrogation of the magnetic field inside the magnetic shield. An early prototype design of the interrogation mechanism is shown in Figure 5.

9 Concept (1) Concept (2) Reject Production Test & Measurement Need Concept (n) Concurrent Design Calculation & Experimentation Simulation Concept (N) Reject Rapid Prototyping Figure 3: Conventional concurrent engineering design flow model. Calculation & Simulation Virtual Prototyping Reject Concept (1) Calculation & Simulation Virtual Prototyping Reject Concept (2) Production Test & Measurement Need Concept (n) Concurrent Design Rapid Prototyping Calculation & Experimentation Simulation Virtual Prototyping Concept (N) Calculation & Simulation Virtual Prototyping Reject Figure 4: Virtual prototyping in the concurrent design flow model.

10 Hall Probe Figure 5: Interrogation mechanism for imaging magnetic flux density inside a HD-TV internal magnetic shield.

11 Proposed research directions We propose to augment our existing capabilities in developing nondestructive evaluation systems with state-of-the-art virtual reality display technology. We will explore and develop novel mechanisms for: (a) Visualizing defect characterization results from NDE procedures. (b) Design process simulations for NDE systems applications. The research project will actively involve the following constituents faculty and technicians, students and industrial consultants. The overarching goal of the proposed research project is to enable the rapid transfer of VR technology to the NDE industry. (c) Description of Research Instrumentation and Needs One of the principal objectives of this research project is to rapidly deploy state-of-the-art VR technology in the NDE industry. The immersive capabilities of the VR system must be sufficient to warrant a significant impact on the design and visualization in NDE systems yet the set-up and operation effort should not be prohibitive. The system should be portable for ease of use. In addition, software support for the system should be adequate so that the learning curve is not excessively steep. We therefore require a lowcost, self-contained, portable VR system that can be shared across the various constituencies faculty, students and industry. We request support to acquire an ImmersaDesk R2 visualization system manufactured by FakeSpace Systems (please see quotation attached in the supplementary documentation). In addition to providing a 82.5 diagonal viewing surface for active stereoscopic imaging, the system provides for fully immersive and tracked user navigation and interaction. The PC controlled system provides software for tracking four sensors attached to the user. Furthermore, the system is portable (the shipping carton rolls through standard sized doors) and set-up time is quoted to be 30 minutes. Existing facilities related to NDE at the Rowan University College of Engineering Faculty research in nondestructive evaluation is facilitated by the ongoing development of a nondestructive evaluation laboratory. This laboratory currently houses high precision linear motorized tables for scanning test specimens, equipment for conducting magnetic

12 flux leakage, DC potential drop, eddy current, ultrasound and microwave NDE tests, along with the associated PC-based data acquisition modules. An Ascension Technology Flock of Birds system provides 3-D motion capture capabilities. The lab contains HP digital storage oscilloscopes, signal generators, microwave network analyzers, UT pulserreceiver modules and a 220A dc power supply. Pentium PCs, Sun and SGI workstations connected to the Engineering LAN allow for on-site digital signal processing. Resident software includes Matlab for algorithm development and Microsoft Visual C++ for software development. A materials testing laboratory is located in the same facility. This houses a 60,000 lb universal testing machine, a metallograph unit and provides other destructive testing capabilities. Also in the engineering building is the machine shop, which allows for rapid fabrication of test specimens. Furthermore, the Rowan College of Engineering has close ties with nearby Camden Community College, that contains a computer integrated manufacturing unit. All of the above facilities provide the Rowan engineering faculty ready access to state-of-the-art materials characterization capabilities. (d) Impact of Infrastructure Projects (RUI Impact Statement attached with the Supplementary Documentation) The educational objective of this project is to provide a unique experience for undergraduate students at Rowan University to conduct this project in a multidisciplinary systems engineering environment and to provide them with skills needed for and desired by industry. We propose to achieve this objective within the setting of the Senior Engineering Clinic. In 1992, local industrialist Henry M. Rowan made a generous donation of $100 million to the then Glassboro State College to establish a high quality engineering school in southern New Jersey. This gift has enabled the university to create one of the most innovative and forward-looking engineering programs in the country. The College of Engineering at Rowan University is composed of four departments: Chemical Engineering; Civil Engineering; Electrical & Computer Engineering; and Mechanical Engineering. Each department has been designed to serve 25 to 30 students per year, resulting in 100 to 120 students per year in the College of Engineering. The size of the college has been optimized such that it is large enough to provide specialization in

13 separate departments, yet is small enough to permit the creation of truly multidisciplinary curricula in which laboratory experiences and design courses are offered simultaneously to students in all four disciplines. The hallmark of the engineering program at Rowan University is the interdisciplinary, project-oriented Engineering Clinic sequence. The Engineering Clinic is a series of courses taken each semester by every engineering student. In the Engineering Clinic, which is based on the medical school model, students and faculty from all four engineering departments work side-by-side on multidisciplinary laboratory experiments, design projects, applied research, and product development. While each clinic course has a specific theme, the underlying concept of engineering design pervades throughout. The clinic progression gives us a way to systematically develop our students as collaborative designers. Freshman engineering introduces design through reverse engineering; at the sophomore level, students learn structured design and get their first, open-ended project experience. Students in the Junior and Senior Engineering Clinics work in multidisciplinary design teams on projects of progressive complexity. The four-year, 22-credit Engineering Clinic sequence offers students the opportunity to incrementally learn the science and art of design by continuously applying the technical skills they have obtained in traditional coursework. This just-in-time approach to engineering design education enables students to complete ambitious design projects as early as the sophomore year. It is within this truly innovative Clinic that we intend to use this project as a Senior Multidisciplinary Design Project. Incorporating design, development and testing of the VR system into the Senior Engineering Clinic will satisfy both technical and educational objectives. From a technical standpoint, the Engineering Clinic will provide the project with a competent, experienced, multidisciplinary workforce of students and faculty from all four disciplines within the College of Engineering. From an educational standpoint, the project will provide senior undergraduate students the opportunity to take part in a complex, multifaceted project culminating in the production of prototype hardware and software. (e) Project and Management Plans As mentioned earlier, this project involves the following constituents:

14 (a) Faculty and technicians: The PI and co-pi s will share in the oversight of the proposed project. Together, the investigators will oversee a team of 5 8 senior undergraduates in this Senior Clinic project. The technicians (Electronics, Computer and Mechanical) will provide support for fabrication and system support. Dr. Shreekanth Mandayam (PI) is graduate from Iowa State University s NDE group, and has been extensively involved in the design and development of nondestructive evaluation systems, both as part of his graduate work and as a faculty member at Rowan University. He has established a thriving NDE laboratory at Rowan, with sponsorship from NSF, US Army TACOM, Water Environment Research Foundation, etc. He also possesses considerable experience in developing virtual reality models for visualization of nondestructive tests in gas transmission pipelines. He has worked in the Iowa Center for Emergent Manufacturing Technology (ICEMT) which has one of the few CAVE VR environments in the world. Dr. John L. Schmalzel (Co-PI) has over 20 years of expertise in instrumentation development for research and product-development applications. He has taught capstone design courses over a 15-year period and is knowledgeable in a variety of prototyping technologies (Schmalzel ). He has prior NSF-ILI project support for laboratory development, so will be able to bring those successes to bear on this project. In particular, he has a track record of results dissemination from similar projects. Dr. Robi Polikar (Co-PI) is also a graduate from Iowa State University s NDE research group. He has considerable expertise in developing defect characterization algorithms for NDE signals and bio-instrumentation. (b) Students: The students will be assigned, as per the usual Clinic method, by the discipline managers (faculty members) from each of the four engineering departments. It is expected that students from all four disciplines will comprise this team. The team will be set up in much the same way as an engineering team in industry, and it will be managed through a combination of small group meetings with individual investigators and entire team meetings for system-level

15 issues. Vertical integration across the graduate (Master s level) and undergraduate curriculum is achieved by the support of 1 graduate student. (c) Industrial affiliates: The collaborating industrial consultant from Physical Acoustics Corporation, Princeton, NJ, will provide input to the faculty, students and technicians in order to facilitate technology transfer. This company has a track record of collaboration with Rowan s NDE group since 1998 (please see letter of support in the supplementary documentation section). The project is expected to be completed in two phases, roughly divided equally over two years. During year 1, the VR system will be purchased, installed and calibrated. The research team will familiarize themselves with the operation of the system and begin developing procedures for integrating this added capability into existing NDE projects in the laboratory. In the second phase of this project procedures will be developed specifically for: (c) Defect characterization of NDE signals characterization results from magnetic and acoustic NDE signals will be visualized (d) Virtual prototyping of NDE systems a magnetic imaging system will be prototyped. The project team will provide recommendations for adapting the procedures developed for other NDE processes. During all stages active feedback from our industrial constituent will be used for developing the research protocols. Dissemination Activity The main venues for the dissemination of research activity related to new contributions to NDE will be at the annual conferences of the Review of Progress in Quantitative Nondestructive Evaluation and the Fall and Spring Conferences of the American Society for Nondestructive Testing. These conferences are well attended both by academia and industry. Experiences in educational scholarship activity as a result of involving undergraduate students in research will be disseminated at the annual conference of the American Society for Engineering Education and the Frontiers in Engineering conference.