Prasad Yarlagadda

Dr Prasad with Prof. Coaldrake, Vice-Chancellor on QUT Innovation Train

Professor Yarlagadda has been the President of the India Australia Society and Vice-President of the Vedantha Society of Australia, Queensland Division. Professor Yarlagadda has also undertaken a number of executive positions in various professional organisations such as: Society of Manufacturing Engineerings, USA, American Society of Mechanical Engineers, USA and Institution of Engineers, Australia.

He has participated in a number of QUT community engagement activities, such as the QUT Innovation Train and others.

Prof. Prasad Yarlgadda Receiving the Honorary Award Prof. Fryderyk Staub Golden Owl Award from the President World Academy of Materials and Manufacturing Engineering, Poland for his OutstandingContribution in the Discipline of Manufacturing and Materials Engineering

Recipient of 2000 Outstanding Scholars of the 20th Century Award in honour of his outstanding contribution in the field of manufacturing engineering, Cambridge, UK, 2000

Recipient of 2001 QUT Outstanding Academic Contribution Award in Research and Scholarship, for his contribution in support of university mission and goals in research and scholarship, 2001

Recipient of 2001 QUT Equity Award for his outstanding efforts in support of QUT’s equity objectives and promotion of good practice and innovation in implementing equity within the university, 2001

Recipient of 2002 Innovation in BEE Education award, as recognition to his contribution in Teaching Innovation, 2002. One award each year is made to a member of staff from B.E.E. Faculty (Across all disciplines of Built Environment and Engineering)

Recipient of 2004 Global Research Award (GCMM) as recognition to his contribution to Manufacturing Engineering Discipline. One award once in two years is made to an outstanding researcher in the manufacturing engineering discipline

In 2007 Professor Prasad Yarlagadda received Fryderyk Staub Golden Owl Award from World Academy of Manufacturing and Materials, Poland for his outstanding contribution to the discipline of materials and manufacturing engineering in the international arena.

Rapid Prototyping Process for Quick Production of Products and Tools

In order to survive in today's competitive environment, companies need to constantly seek technologies to shorten product development cycle, reducing design & manufacturing lead-time and improving time to market. As industries press for faster development, the ability to have a full-functioning working assembly in hand in a short time frame is more and more important.

Computer Aided Design (CAD), and Rapid Prototyping and Tooling (RP&T) are a combination of tools and latest manufacturing technologies which are required to keep up with this time-sensitive pace and help to develop new products faster than before. Technological advancements in communications, automation, and computers continue to fuel the growth of Rapid Prototyping (RP) since it came to the forefront in 1986. RP and its derivative Rapid Tooling (RT) have become an integral part of the design and manufacturing processes. RT has the potential to dramatically improve the speed and cost of tool development.

Using CAD, electronic data transfer, process simulation, and RP&T technologies, tooling cost and development times can be reduced, especially when tools geometry (part complexity or specific geometry features) make traditional / conventional machining difficult. By reducing tooling costs, RP&T enable high volume process, such as press metal forming tool, to be competitive at lower production volumes. Prof. Yarlagadda worked with a number of both Australian and international manufacturing industries in reducing lead time in new product development by adopting combination of both traditional and rapid prototype manufacturing techniques.

Process of Tool Production for Sheet Metal Forming Applications

Computer Aided Design and Computer Aided manufacturing (CAD/CAM) applications for tool and die making is becoming increasingly attractive to traditional / conventional machining. Rapid prototyping also called free form fabrication, uses additive process to create a physical geometry directly from a CAD file, replacing conventional methods that remove materials. Rapid tooling typically requires several steps to create the tools.

In an indirect method, a master model (pattern) is created by RP and used other techniques or processes to form the tool. On the other hand, a direct method produces the tool directly from RP model. RP&T along with press metal forming tool have combined to offer an alternative to conventional machining processes. This comes at a time when more and more emphasis is being placed on minimizing the inherent time and cost associated with the development of a product. RP&T have found a role by bridging the design and manufacturing entities by hastening the time to market a product from conception.

The future of these technologies appears to be bright. This is supported by the intensive research efforts being conducted at universities, research institutions, and industries. Prof. Prasad and his team worked extensively with a number SMEs, and tooling industry in developing quick tools for various sheet metal applications.

Biocomposites synthetic polymer and HA for scaffold applications: Coutesy Dr. Philip Cheang, NTU

Titanium and its alloys are widely used in orthopedic surgeries. This is because of their outstanding biocompatibility and mechanical properties. Their interactions with cells depend mostly on surface properties. The tissue integration of a biomaterial is a critical factor in determining how well the implant material commonly used in bone surgery or reconstruction is incorporated into the human body. The biocompatibility of a biomaterial is highly related to the behavior of the cells in contact and in particular the cell adhesion to its surface.

A bio-scaffold can be broadly termed as a structure used to substitute an organ either permanently or temporarily to restore functionality. The material that can be used varies with the application intended. Tissue Engineering is one such application demanding certain requirements to be met before it is applied. One of the applications in tissue engineering is the tissue scaffold, which provides either a permanent or temporary support to the dam aged tissues/organ until the functionalities are restored. A biomaterial can exhibit specific interactions with cells that will lead to stereotyped responses. The use of a particular material and morphology depends on various factors such as Osteoinduction, Osteoconduction, angiogenesis, growth rates of cells and degradation rate of the material in case of temporary scaffolds etc.

Prof. Yarlagadda and his team consists of Prof. Ross Crawford, Prof. Kunle Oloyele, Prof. Sreejith, Assoc. Prof. Yin Xiao and others are working on number of issues related to permanent scaffolds by using Titanium and its alloys for various tissue engineering applications. Prof. Prasad Yarlagadda has extensive collaboration with a number of researchers from various international institutes such as Singapore Institute of Manufacturing Technology, Singapore Government Hospital, Bio Scaffold Pty. Ltd in development permanent scaffolds for tissue engineering.

Schematic diagram of experimental setup for process control and Weld Automation

Recent developments in materials and material joining have increased the scope and extent of their areas of application. However, stern market demand for the improved weld quality necessitates the need for automation of the welding processes. As a result, improvements in the process parameter feedback, sensing and control, are necessary to successfully develop the automated control technology for the welding processes.

Hence, several aspects of the GMAW-P process have been investigated in this study in order to improve its control techniques. This investigation explores the effects of different process parameters on welding process. Prof. Yarlagadda, Dr. Praveen Posinasetti and their team have extensive international collaboration in this area with various world famous researchers and institutes such as Prof. Sehun Rhee from HanYang University, Korea, Dr. B.Y. Kang, Dr. M.J. Kang from Korean Institute of Industrial Technology, Prof. Ill-Soo Kim from Mokpo National University, Korea.

Schematic diagram of the microwave system for manufacturing applications

Microwave technology is one of the alternative high energy technologies used for number of manufacturing related applications. Microwave offers the possibility of uniform curing of the materials by generating instantly heat in the entire part independently of its shape complexity and dimensions. Materials for microwave heating need to be electrically non-conductive and should have dipole structure. The dipoles are polarised at microwave frequency.

When the frequency is high, such as at microwaves, the dipole can not follow with the reorientation of the electric field and at this point microwave energy is converted into heat. Effective microwave heating is achieved, when the rate of microwave power absorption is greater than the rate of heat dissipation through convection or conduction During microwave applications the environment is filled with electromagnetic waves at all times. Light, X-irradiation, TV, AM and FM radio waves, ultraviolet, infra-red and microwaves are some of the manifestations of these waves.

Microwaves occupy the part of the spectrum from 300 MHz to 300 GHz. Most applications of microwave technology make use of frequencies in the range of 1 to 40 GHz. Of particular importance to this study is the manner in which microwaves interact with the materials. When microwave impinges upon a material, the material preferentially absorbs the waves. The frequencies that are absorbed called the resonant frequencies of the material, and are dependent upon its molecular composition. Microwaves travel in the same manner as light waves and they can be reflected by metallic objects, absorbed by some dielectric materials, transmitted without significant absorption through other dielectric materials. Prof. Yarlagadda and his team did extensive study of microwave energy applications for various manufacturing processes and product developments.

Solar Energy Concentrator Developed at Queensland University of Technology

Solar radiation has served as an energy source since the beginning of life and, the living creatures illuminated by the terrestrially available sunlight have been using it in many different ways. A variety of solar energy technologies are being developed to harness the available solar radiation but its utilization is still an expanding field of human endeavour. Researchers continue to discover new ways to utilize this “free delivered” power and apply it to different energy consuming processes. Beam solar radiation that intercepts the earth is fairly uniform with a broader spectral range and relatively low intensity compared to other modern sources of electromagnetic radiation.

Therefore, when high temperatures are desired, concentration of the incident solar radiation becomes necessary. Solar concentration technologies have made considerable progress over the years and recent achievements have contributed to further increasing the recognition of solar power as a potentially viable source of renewable energy. Radiation processing of materials using ionizing electromagnetic energy has had practical application for many years. Prof. Prasad, Dr. Loubmir and his other colleagues developed a Solar Energy Concentration system and used for manufacturing applications such as joining and other studies as ageing of polymers ar among others.

A PDM based Integration Framework

Manufacturing, particularly tooling companies, which are typical small and medium-sized enterprises (SMEs), usually operate in a make-to-order fashion. They have to rapidly respond to customers to gain business opportunities in a contracting market. These tooling companies should be flexible and innovative, taking into consider the size and structure. However, they are still faced with the challenge of frequently changing customer requirements. As the product market lifecycle is becoming short, tooling industry also have to shorten their business cycle to rapidly respond to these demands. To survive in such a competitive market, many manufacturing companies are seeking solutions to improve their overall business performance by integrating critical business processes, i.e. design, planning and production.

At present, most of tooling companies are faced with an inefficient computing environment that lacks of integration and is not capable of effective supporting information sharing and exchange. As a result, the overall business performance is not improved as expected though the efficiency of ndividual activities is increased by individual software systems. Prof. Yarlagadda, Mr. Ni and other team members attempted to design and develop of a PDM-based system for the integration of critical business process, which are design, planning and production, to achieve higher business performance.

Firstly, the PDM frame is extended to manage non-engineering data and support business activities of planning and production. Then, the integration-supported models, including design model, routing planning model and task model, are discussed from the perspectives of information association and process automation. The integration of workflow management to streamline business processes is also investigated.

Experimental setup for process modeling and control of pulse gas metal arc welding of aluminum

Name: Praveen Posinasetti

Year: 2007

Course: Ph.D.

College: QUT

Recent developments in materials and material joining (specifically Aluminum and Pulse Gas Metal Arc Welding (GMAW-P) technology) have increased the scope and extent of their areas of application. However, stern market demand for the improved weld quality necessitates the need for automation of the welding processes. As a result, improvements in the process parameter feedback, sensing and control, are necessary to successfully develop the automated control technology for the welding processes. Hence, several aspects of the GMAW-P process have been investigated in this study in order to improve its control techniques. Analysis showed that transition between the different metal transfer modes is strongly influenced by the electrode extension. Lower electrode extension reduced the number of droplets detached per pulse, while at higher electrode extension, spray mode is observed due to increased influence of the resistance heating.

Analysis of the current and voltage signals were correlated with the high speed films. A simple derivative filter was used to detect the sudden changes in voltage difference associated with metal transfer during GMAW-P. The chosen feature for detection is the mean value of the weld current and voltage. A new algorithm for the real time monitoring and classification of different metal transfer modes in GMAW-P has been developed using voltage and current signals. The performance of the algorithm is assessed using experimental data. The results obtained from the algorithm show that it is possible to detect changes in metal transfer modes automatically and on-line. Arc stability in the GMAW-P has a close relationship with the regularity of metal transfer, which depends on several physical quantities (like voltage, current, materials, etc.) related to the growth and transfer of the metal droplet. Arc state in GMAW-P can be assessed quantitatively in terms of number of drops per pulse, droplet diameter and arc length. In order to assess the arc state in GMAW-P quantitatively, statistical and neural network models for number of drops/pulse, droplet diameter and arc length were developed using different waveform factors extracted from the current waveform of GMAW-P.

To validate the models, estimated results were compared to the actual values of the number of drops per pulse, droplet diameter and arc length, observed during several welding conditions. Determination of stable one drop per pulse (ODPP) parametric zone containing all the combinations of peak current (IP), base current (IB), peak time (TP), and base time (TB) that results in stable operation of GMAW-P, is one of the biggest challenges in GMAW-P. A new parametric model to identify the stable ODPP condition in aluminium which also considers the influence of the background conditions and wire feed has been proposed. Finally, a synergic control algorithm for GMAW-P process has been proposed. Synergic algorithm proposed in this work uses the sensing and prediction techniques to analyse state of the arc and correct the pulsing parameters for achieving the stable ODPP. First arc state is estimated using the signal processing techniques and statistical methods to detect the occurrence of short circuit, unstable ODPP or multiple drops per pulse (MDPP) in GMAW-P system. If the arc state is not stable ODPP, then parametric model and genetic algorithm (GA) is used to assess the deviation of the existing pulsing parameters from the stable operation of GMAW-P process and automatically adjust pulsing parameters to achieve stable ODPP.

Test rig for pealing a pumpkin

Name: Emadi Bagher

Completion Year: 2006

Course: Ph. D.

College: QUT

Tough-skinned vegetables such as pumpkin and melon currently are peeled either semi-automatically or automatically. The main limitation of both methods, especially for varieties with an uneven surface, is high peeling losses. Improvement of current mechanical peeling methods and development of new mechanical methods for tough-skinned vegetables which are close to the “ideal” peeling conditions using mechanical properties of the product were the main objectives of this research. This research has developed four innovative mechanical peeling methods on the basis of the mechanical properties of tough-skinned vegetables.

For the first time, an abrasive-cutter brush has been introduced as the best peeling method of tough-skinned vegetables. This device simultaneously applies abrasive and cutting forces to remove the peel. The same peeling efficiency at concave and convex areas in addition to high productivity are the main advantages of the developed method. The developed peeling method is environmentally friendly, as it minimises water consumption and peeling wastes. The peeling process using this method has been simulated in a mathematical model and the significant influencing parameters have been determined. The parameters are related to either the product or peeler. Those parameters appeared as the coefficients of a linear regression model. The coefficients have been determined for Jap and Jarrahdale as two varieties of pumpkin. The mathematical model has been verified by experimental results.

The successful implementation of this research has provided essential information for the design and manufacture of a commercial peeler for tough-skinned vegetables. It is anticipated that the abrasive-cutting method and the mathematical model will be put into practical use in the food processing industry, enabling peeling of tough-skinned vegetables to be optimised and potentially saving the food industry millions of dollars in tough-skinned vegetable peeling processes.

Schematic view of solar energy concentrator (SEC)

Name: Lou Stoynov

Completion Year: 2006

Course: Ph. D.

College: QUT

Various solar energy technologies are being developed to harness the available environmentally friendly and sustainable solar radiation. New ways of utilizing this “free” power for different energy consuming processes continue to be created. In this thesis, a multi-stage solar energy concentrating system has been developed and its feasibility as a radiation source for polymer processing has been explored.

The solar energy concentrator (SEC) facility comprises a modified Cassegrainian configuration combined with auxiliary imaging and non-imaging optics, serving as an alternative energy source for polymer joining, ageing and adhesive curing. Modeling and improvement of various aspects of the operation and performance of the SEC facility have been implemented. Optical ray tracing models of the Cassegrainian concentrator with various conventional imaging components and nonimaging concentrators have been created to optimize the optical layout and system efficiency. On their basis, combined 3D ray tracing computer models integrated with the mechanical components have been developed to simulate the entire SEC facility and predict the image size, location and orientation.

Additionally, the energy transfer, radiation absorption and heat generation and transfer in the irradiated polymer have been modeled in order to study the radiation–polymer interaction. One novel contribution of this research is the enhancement of the image forming concentrator with non-imaging cone-like concentrators (conical and compound parabolic concentrator (CPC)), utilizing their inherent disadvantage of excessive length. Compared to the refractive type means of transmitting concentrated solar radiation, the truncated cone and CPC concentrators have been found more efficient enhancing further the concentration and widening the utilized spectral range.

The experimental studies have demonstrated that transparent and colored, similar and dissimilar polymers can be successfully joined using the SEC facility. The especially developed through-transmission technique removes the need to use a special absorbing medium of the radiant energy required by current advanced welding techniques. The tensile strengths of the joints achieved are comparable to those achieved for similar polymers with other advanced plastic joining methods. The results from the polymer ageing experiments have shown that ultraaccelerated exposure to concentrated sunlight can be performed with the SEC facility without introducing spurious failure mechanisms. Based on the preliminary investigation on adhesive curing utilizing concentrated solar radiation, it has been concluded that with carefully chosen light-curing adhesives solar radiation can be a useful radiation source for adhesive curing.

EDM Facility to study rapid tooling concepts

Name: Ricky Blom

Completion Year: 2005

Course: M.Eng. (Research)

College: QUT

To survive in today’s manufacturing environments companies must push the standards of accuracy and speed to the highest levels possible. Electro Discharge Machining (EDM) has been used for over 50 years and recent developments have seen the use of EDM become much more viable. The goal of this research is to produce and evaluate electrodes produced by different manufacturing methods. The use of electroforming and spray-metal deposition has only recently become viable methods of producing usable rapid tooling components. The speed and accuracy as well as the cost of manufacture play a vital role in the tool and mould manufacturing process. Electroforming and spray-metal deposition offer an alternate option to traditional machining of electrodes. Electroforming is one method of producing electrodes for EDM.

The fact that electroforming can be used to produce multiple electrodes simultaneously gives it the advantage of saving on costs when multiple electrodes are needed. Spray-metal deposition offers another alternative that is much cheaper and relatively faster to manufacture. The used of these non-traditional manufacturing methods in this research are compared to the performance of traditional solid electrodes in terms of machining time, material removal rate, tool wear rates and surface roughness at several standard machining settings. The results of this research are presented in this thesis along with conclusions and comments on the performance of the different methods of electrode manufacture.

The major findings of the research include the solid electrodes performed better than the electroformed electrodes in Material Removal Rate (MRR), Tool Wear Rate (TWR), and Surface Roughness (Ra) at all machine settings. However it was found that the production cost of the solid electrodes was six times that of the electroformed electrodes. The production of spray metal electrodes was unsuccessful. The electrode shell walls were not an even thickness and the backing material broke through the shell making them unusable. It is concluded that with further refinements and research, electroforming and spray metal processes will become an extremely competitive method in electrode manufacture and other rapid tooling processes.

Modelling of microwave curing process

Name: Klaus Berg

Completion Year: 2003

Course: Ph. D.

College: QUT

In this research microwave curing is used to support fast curing in order to prevent changes to the form and shape of a selective applied layer. In this investigation the layer consists of a liquid mixture of epoxy resin with aluminium particles is cured using microwave heating and is further used in rapid product development. The issue of statistical modelling of the fast curing process of thin epoxy resin layers using microwave heating is addressed in this paper.

The modelling by a linear regression method is based on information available from the curing process as well as from data collected performing the Dynamic Scanning Calorimetry analysis. To reach the state of dimensional stability, the curing temperature of the layer material was controlled using two options. First, through the reduction of the microwave power and second, through altering the turntable speed so that the microwave exposure time of the layer was monitored. This operation was controlled using appropriate computer software.

Experimental setup for Corrosion studies

Name: Abdalaziz Barkat Alruwili

Year: Current

Course: Ph.D.

College: QUT

The aim of this research project is to investigate the corrosion of mild steel in caustic solutions with respect to the metal loss problem found in the bauxite refineries’ mild steel heat exchangers. This research has positive benefits for the oil refinery industry as the possible findings will allow companies to take advantage of the research results in applying new methods to manage this problem of corrosion in piping and in other mechanical parts used in oil refinery plants. It is important to industry as it will improve the life of equipment and reduce maintenance/replacement costs of parts. It will also reduce downtime meaning an increase in productivity and profit.

Australia Post’s Flat Mail Optical Character Reader (FMOCR)

Name: James P Fox

Year: Current

Course: M.Eng. (Research).

College: QUT

Machine downtime, whether planned or unplanned, is intuitively costly to manufacturing organisations, but is often very difficult to quantify. The available literature showed that costing processes are rarely undertaken within manufacturing organisations. Where cost analyses have been undertaken, they generally have only valued a small proportion of the affected costs, leading to an overly conservative estimate.

This project aimed to develop a cost of downtime model, with particular emphasis on the application of the model to Australia Post’s Flat Mail Optical Character Reader (FMOCR). This has been the first time that Post has endeavoured to examine the cost of downtime. It is also one of the very few methodologies for valuing downtime costs that has been proposed in literature. The work undertaken has also demonstrated how the cost of downtime can be incorporated into machine performance analysis with specific application to identifying high costs modules. The outcome of this work has both been the methodology for costing downtime, as well as a list of areas for cost reduction.

Enterprise system intergration for PDM

Name: Qianfu Ni

Year: Current

Course: Ph. D.

College: QUT

Currently, much time is needed to individualize an enterprise system to satisfy the requirements of a particular company because business practices vary from one company to another and the enterprise systems can not be flexibly changed to support different practices. This stretches the deployment cycle and increase the implementation cost. It also constrains the changes of business practices for new business opportunities. Therefore, the flexibility of enterprise systems is gaining the attention of solution vendors and researchers.

A research has been conducted on semantic representations that enhance the flexibility of enterprise systems and enable enterprise systems to be rapidly tailored for different companies. The core of the concept is to decouple various logics from computer programs and represent the logics in a semantic manner. To achieve semantic representations, XML-based declarative language has been developed for representing various logics. The paper elaborates semantic representations of information entities, entity relationships, functional components and graphical environments. A business process management system developed based on semantic representations has also been briefly introduced.

Schematic illustration of suspicious activity monitoring

Name: Arnold Wiliem

Year: Current

Course: Ph. D.

College: QUT

There is a necessity to detect suspicious behaviour within surveillance systems as this advancement alleviates problems caused by human factors in the detection chains. However, detecting suspicious behaviour could be very challenging since the notion of suspicious is not always the same from one surveillance area to another. Although, current approaches allow people to frame what suspicious is, they are not robust in term of context variations. This research is aimed at the development of methods for identifying suspicious behaviour from video data in various contexts.