August 28 ~ 31, 2019 |Hsin Chu, Taiwan

Keynote Speaker

Noise and Vibration Mitigations for Aeronautical and Aerospace Applications

Li Cheng

Chair Professor of Mechanical Engineering Department of Mechanical Engineering, Hong Kong Polytechnic University

Abstract

The issue of vibration and noise inside an enclosure is a typical vibroacoustic problem of great relevance to various aeronautical and aerospace applications, exemplified by noise inside aircraft cabin and space vehicles. The growing importance of the vibration/noise related problems and the necessity for their consideration at the design stage is being witnessed with an increasing awareness. To tackle the problem, a comprehensive set of technological knowhow, including the development of efficient and flexible modelling and optimization tools, understanding of the underlying physics as well as the development of effective control means, is indispensable. This talk reviews and highlights some of the past and on-going work undertaken by the speaker and his team in this area. Topics include the discussions on the general structural-acoustic coupling problem, development of efficient simulation, analysis and optimization tools, design of light weight strictures as well as various passive and active control techniques, under the context of interior noise and vibration control for aircraft and space structures.

Bio-sketch

Dr. Li Cheng is currently a Chair Professor and the Director of Consortium for Sound and Vibration Research (CSVR) at the Hong Kong Polytechnic University. He received his BSc degree from Xi'an Jiaotong University, DEA and Ph.D. degrees from the Institut National des Sciences Appliquées de Lyon (INSA-Lyon), France. After two years in Sherbrooke University, he started his academic career at Laval University, Canada in 1992, rising from an assistant professor to Associate/Full Professor, before coming to Hong Kong in 2000, where he was promoted to Chair Professor in 2005 and was the Head of Department from 2011 to 2014. Dr. Cheng published extensively in the field of sound and vibration, structural health monitoring, smart structure and fluid-structure interaction. He is an elected fellow of the Acoustical Society of America, Acoustical Society of China, IMechE, Hong Kong Institution of Engineers and Hong Kong Institute of Acoustics. He currently serves as Deputy Editor-in-Chief and Receiving Editor of Journal of Sound and Vibration, Associate Editor for the Journal of Acoustical Society of America, Associate Editor of Structural Health Monitoring: An International Journal and editorial board member of 6 other journals. Dr. Cheng also been a Plenary/Keynote Speaker at conferences in the USA, UK, France, Japan, Greece, India, South Korea, Poland, Bangladesh and China, including some of the most prestigious conferences in his field such as 47th Inter-noise, 23rd ICSV, 13th RASD, 15th APVC and 12th ICOVP. He also served as the general Chair of the 46th International Congress on Noise Control Engineering (Inter-noise) and the Chair of 14th and 17th Asia Pacific Vibration Conference (APVC). Dr. Cheng was the President of the Hong Kong Society of Theoretical and Applied Mechanics. He is also a board director of both IIAV (International Institutes of Acoustics and Vibration) and I-INCE (International Institutes of Noise Control Engineering).

Keynote Speaker

Hybrid2 Rocket Propulsion Technology and Its Outlook in Future Space Age

Jong-Shinn Wu

Distinguished Professor of Mechanical Engineering Department, National Chiao Tung University, Taiwan

Abstract

Hybrid rocket propulsion technology has recently attracted tremendous attention, mainly because of its important features which include system simplicity, high level of operation safety, good throttling capability, and good propulsion performance, to name a few, as compared to solid and liquid rocket propulsion technologies. The above possibly lead to a very cost-effective operation for future space application such as sending micro/nano satellites into low earth orbit (LEO). In this talk, the speaker reviews the worldwide trend of the development of hybrid rocket propulsion technology and proposes a new Hybrid2 Propulsion Technology which takes advantage of the propulsion performance and industrial infrastructure in Taiwan. Its current status of application in an on-going project of ARRC (Advanced Rocket Research Center), developing a two-stage sounding rocket flying to 100 km in apogee in 2021, is described along with other advanced subsystems including the avionics, TT&C and light-weight structure.

Bio-sketch

Dr. Jong-Shinn Wu is currently a Distinguished Professor and the Director of Advanced Rocket Research Center (ARRC) at National Chiao Tung University. He received his BS and MS degrees both in Mechanical Engineering, National Taiwan University, Taiwan, and his PhD degree in Aerospace Engineering, University of Michigan, USA. After being a postdoc at UM until late 1995, he returned to Taiwan and worked at the National Space Organization (NSPO) for two years. He then joined the Mechanical Engineering Dept. of National Chiao Tung University in 1998 till now. He is now a Distinguished Professor, the founder/director of Advanced Rocket Research Center (ARRC) and the president of Taiwanese Association of Plasma & Technology (TAPST). He has received the 2018 Outstanding Research Award, Ministry of Science & Technology (MOST), Taiwan. He is an elected ASME Fellow, AIAA Associate Fellow, and AIAA Hybrid Rocket Technical Committee member. His research interests include rarefied gas dynamics modeling, rocket propulsion, non-equilibrium plasma modeling, atmospheric-pressure plasma applications (in biomedicine, agriculture, and industry), and general parallel scientific computing.

He has constantly given invited/plenary lectures in parallel simulations of plasma and rarefied gas dynamics internationally. He was the Associate Editor of the International Journal of Plasma Science & Engineering (2008-2010), currently an Editorial Board member of Int. J. Theoretical & Applied Mechanics (2006~) and a Guest Editor of Computers & Fluids (2010-2012), IEEE Transactions on Plasma Science (2014-2016) and Journal of Computers and Mathematics with Applications (2015-2016). He has been the Chair and members of the Advisory/Organizing Committee of many important international conferences in plasma and computational fluid dynamics for the past 10 years. In addition, he will co-chair another two important upcoming conferences, which include the 16th International Conference on Flow Dynamics (Sendai, Japan) in 2019 and the 32nd International Symposium on Rarefied Gas Dynamics (Seoul, South Korea) in 2020.

Keynote Speaker

Development Status of Aerospace Composite Materials Technology in Korea

Changduk Kong

Department of Aerospace Engineering, Chosun University, 309 Pilmun-daero, Dong-gu, 61452, Gwangju, Republic of Korea

Abstract

Composite materials are ideal for structural applications where high strength-to-weight and stiffness-to-weight ratios are required. Aircraft and spacecraft are typically weight sensitive structure, in which composite materials can be cost-effective, for instance, about 800 USD/lb for commercial aircrafts and about 30,000USD/lb for spacecraft. Composite materials are often not only to improve the stiffness-to-weight ratio or strength-to-weight ratio or to improve toughness in mechanical design but also to reduce thermal expansion, or to maximize heat transfer, or to minimize thermal distortion in thermo-mechanical design. Due to these advantages most present aircrafts and spacecraft have been designed by composite materials. For example, new commercial aircrafts A350 and B787 use 53% and 50% composites among total airframe weight, respectively, and Eurofighter Typhoon uses 82 % composites in surface area ratio. Among composite materials the carbon composite materials are mostly used due to relatively better mechanical properties of high specific strength and specific stiffness, almost zero thermal expansion ratio, longer fatigue life, etc.

Recently, Korea has been developed several military and civil aircrafts such as KT-1 basic trainer, T-50 advanced supersonic trainer, FA-50 light attack fighter, KUH helicopter, KC-100 light airplane, LAH (Light Armed Helicopter)/LCH(Light Civil Helicopter) and KFX Next Generation Fighter, airframe structural components of Airbus and Boeing aircrafts as a risk-share-partner, UAVs, missiles, launcher vehicle, satellites, etc. using composite materials.

This presentation introduces present development status of aerospace composite materials technology including design, analysis and manufacturing, inspection and test in deveolped by grobal as well as Korean aerospace industries.

Bio-sketch

Prof. Changduk Kong graduated with a BSc in Aerospace Engineering from the Korea Aerospace University-National (Hons.) and a PhD in Aerospace Engineering from the Osaka Prefecture University, Japan.

He worked as Head of the Aero-Propulsion Division of ADD (Agency for Defence Development in1978-1994. He served as Professor at Department of Aerospace Engineering of Chosun University during 1994-2016, and was appointed as Dean of the School of Aerospace and Naval Architecture Engineering in 1999 and 2005-2006, and Dean of the Facility Management Office at Chosun University in 2011-2012. He has served as International Visiting Professor at Department of Aerospace Engineering of IIT(Indian Institute of Technology) Kharagpur, India in 2017-2021, Invited Professor at School of Aerospace and Mechanical Engineering of Korea Aerospace University, in 2016-2019, Invited Professor at Summer School of BUAA(Beijing University of Aeronautics and Astronautics), China in 2017-2019, and Emeritus Professor at Department of Aerospace Engineering of Chosun University since 2016. He was invited as Visiting Professor at Department of Aeronautics of Imperial College, UK in 2001-2002.

Prof. Kong has contributed greatly to the development of Aerospace Engineering in Korea, primarily through his roles as a non-standing Director of KIAST(Korea Institute of Aviation Safety Technology) in 2015-2018, a non-standing Director of AMRC(UK)-Korea in 2016-2020, CTO of EGT Company, President of KNST(Korea Society for Naval Science and Technology) in 2017-2018, President of SASE(The Society for Aerospace System Engineering) in 2013-2016, President of ICRC (International Collaboration Research Centre in Natural Composites, Chosun University in 2012-2014, President of KSAS(The Korean Society for Aeronautical and Space Sciences in 2010, President of KSPE(The Korean Society of Propulsion Engineers in 2007-2008, Chair of Cycle Innovation-IGTIASME in 2009-2011, President of RIME(Research Institute of Mechanical Engineering-Chosun University) in 2006-2008, and First Lieutenant of ROKAF(Republic of Korea Air Forces) in 1974-1978.

He has served as Editorial Board Members of IJTJ(International Journal of Turbo & Jet Engines), IJCM(International Journal of Composite Materials), CJS(Chinese Journal of Aeronautics) and AEAT(Aircraft Engineering and Aerospace Technology) since 1998, and Editor-in-Chief of JKSAS(Journal of Korean Society for Aeronautical and Space Science) and JKSPE(Journal of Korean Society of Propulsion Engineers) in 2006-2010. He received the Korean National Decoration in Science, Academic Achievement Awards from KSAS, SASE and KSPE, Defence Science Medals and the 2015 KAI-KSAS Prize for his scientific achievement and contribution to Korean aerospace development. Prof. Kong has authored and co-authored more than 616 papers including 67 SCI journal papers, and has received numerous lecture invitations from companies, research institutes and universities and delivered eleven keynotes and invited lectures at international conferences. He has organized 26 national conferences, forums and workshops and was co-organiser on four international conferences.

Keynote Speaker

The Space Development Plan of Taiwan

Chun-Liang Lin

National Space Organization (NSPO)



Abstract

After several rounds of expert and review meetings, Taiwan’s Third Phase National Space Technology Development Long-term Plan (hereafter called the 3rd Phase Space Development Plan) was officially approved by the Executive Yuan at the beginning of this year.

The planning and formulation of the 3rd Phase Space Development Plan is based on the previous two space development plans, especially on the successful operation of FORMOSAT-5. This plan has several new features compared with the previous twos. First, NSPO will establish three satellite constellations, containing optical and synthetic aperture radar satellites, with properties of multiple revisits and all-weather for Taiwan to meet the needs of national security, disaster prevention, environmental monitoring and others.

Second, NSPO will challenge cutting-edge space missions to conduct related research for outer space exploration. Finally, promoting the development of Taiwan's space industry is listed as one important goal for this 3rd Phase Space Development Plan, and NSPO plans to establish a supply chain for Taiwan satellite industry through 10 Taiwan-made satellites.

This talk will present an overview of Taiwan’s Space Development Plan and describe NSPO’s planning to promote the development of local space industry in details.

Bio-sketch

EDUCATION
  • 1986-1991: Ph.D in Aeronautics and Astronautics, National Cheng Kung University, Tainan, Taiwan
  • 1984-1986: MS in Automatic Control Engineering, Feng Chia University, Taichung, Taiwan
PROFESSIONAL EXPERIENCE
  • 2018 – Present: Director General, National Space Organization (NSPO), Taiwan
  • 2003-2018: Chair Professor, Department of Electrical Engineering, National Chung Hsing University, Taiwan
  • 1995-2003: Professor, Department of Automatic Control Engineering, Feng Chia University, Taichung, Taiwan
  • 1991-1995: Scientist, Chung Shan Institute of Science and Technology, Taiwan
HIGHLIGHT OF ACADEMIC/INDUSTRY INTEREST
  • Academic interests: biometrics, control theory and applications, systems biology, guidance and control
  • Industry interests: electric vehicle braking/driving control, vehicle wireless recharge, mechatronics
Academic Award:
  • Outstanding Research Award, Ministry of Science and Technology, Taiwan (2000, 2003, 2010)
  • The Academic Award, Ministry of Education, Taiwan (2014)
  • Outstanding Merit Research Fellow Award, Ministry of Science and Technology, Taiwan (2018)

Keynote Speaker

Disturbance Region Update Method for Compressible Flows

Jiang Chongwen

School of Aeronautic Science & Engineering in Beihang University



Abstract

The computational fluid dynamics plays a significant role in the aerodynamic design, optimization and analysis of aerospace vehicles. For the steady and unsteady simulation of vehicles operating in compressible flows, such as rockets and airplanes, the time-marching technique is in common used owing to its wide application range. Generally, the time-marching technique is performed in a fixed preassigned computational domain and updates all grid cells at every time step. However, this crude way does not take the characteristics of the time-marching solution process into account, resulting in a considerable amount of worthless computational effort. In this talk, I will analysis the features of the time-marching solution process, introduce our new acceleration methodology that takes advantage of these features, which is named the disturbance region update method (DRUM), with a view to applicating DRUM on the aircraft design and performance analysis. Numerical tests demonstrate that, as compared to the conventional update way, DRUM can accomplish remarkable convergence speed for a wide range of Mach and Reynolds numbers, reaching up to 40%~70%; it may also save notably in terms of the maximum memory requirements, especially for the supersonic problems; it also equips the capacity of identifying the disturbed region and the viscous-dominated region to assist in the analysis on the physical characteristics of the flowfield.

Bio-sketch

Jiang Chongwen is interested in the computational fluid dynamics, aircraft aerodynamics and the environment fluid mechanics. Now he is the deputy dean and an associated professor of the School of Aeronautic Science & Engineering in Beihang University and the staff of the National Laboratory for Computational Fluid Dynamics. He published over 40 articles in the SCI- and EI-covered journals and held about 20 Chinese patents.

Keynote Speaker

Simultaneous distribution and sizing optimization for stiffened shell by improving the genetic algorithm with two-level approximation

Shenyan Chen

School of Astronautics, Beihang University(BUAA)


Abstract

Stiffened shells have widespread applications in weight-critical engineering structures. Owing to the high ratio of rigidity/weight, they show good mechanical properties under different loading cases with relatively low weight. For this kind of structure, how to distribute the stiffeners and design their cross-sectional dimensions to obtain better mechanical performance is an important problem. In the present work, an efficient numerical algorithm was proposed to optimize the distribution and size of stiffeners simultaneously. An optimization model of stiffeners, including two kinds of design variables, is established. In order to solve this non-linear mathematical programming problem, a two-level approximation strategy was implemented by insetting Genetic Algorithm (GA). The original implicit problem was transformed as a first-level approximation problem, which involves both the topology and size variables. Then, GA addresses the mixed variables. The individuals in the GA are coded by topology variables, and when calculating an individual’s fitness, the second-level approximation problem is embedded to optimize the size variables. Numerical example and practical application showed the feasibility and efficiency of the proposed method.

Bio-sketch

Chen Shenyan is now an associate professor in School of Astronautics, Beihang University (BUAA). She gives courses to both Chinese and foreign students on the major of Aerospace Engineering. Her interested research areas include structural optimization and its engineering application, structural analysis and design, composite structure analysis and optimization. In the last years, she joined series research projects on structural optimization and advanced light-weight technology for engineering structures. She developed a new style Engineering Structural optimization System of Spacecraft – ESOSSII, which has been successfully applied in structural optimization of practical engineer. She has published or presented more than 50 papers in journals and international conferences.

Keynote Speaker

Transient Response Analysis of Four-parameter Power Law Functionally Graded Shells of Revolution

Dipak Kumar Maiti

Department of Aerospace Engineering Indian Institute of Technology



Abstract

Shell structures are extensively used in industries like nuclear, aerospace and chemical. These structures during their service life are subjected to combined effects of intense mechanical and thermal loads and therefore are required to operate safely under these conditions. A deliberate and gradual gradation of materials like ceramic and metal in functionally graded (FG) structures provide them the ability to withstand mechanical loads under severe thermal environment.

The present work focuses on studying the effect of thermal environment on free vibration behavior of FG shell of revolution. The reference surface of the shell has been defined in orthogonal curvilinear coordinate system and the displacement field is given according to higher-order shear deformation theory (HSDT). The volume fractions and hence the properties of the primary constituents of FGM, ceramic and metal, are assumed to be varying along the thickness of the shell in accordance to four-parameter power law. The inner surface of the shell is subjected to high temperature environment while the outer surface is at room temperature and vice versa and the temperature profile along the thickness of the shell has been obtained by numerically (finite element) solving the steady-state heat conduction equation in the coordinate system appropriate for the kind of shell considered for the problem. Finite element method has been used to discretize the equation of motion and the domain using isoparametric eight noded curved element. Variation in thermal conductivity along the thickness of the shell can have temperature distribution different from linear and may affect the free vibration response of the shell. The material properties of both the constituents are considered to be temperature dependent. The convergence study and validation for both heat conduction equation and free vibration of shell structures has been done. Parametric studies involving the effect of geometries of the shell, parameters of power law, temperature boundary conditions, structural boundary conditions and material composition on inner and outer faces of the shell will be presented in the final version of the manuscript.

Bio-sketch

Dr. Dipak Kumar Maiti was employed as Junior Project officer after one and half years of his doctoral research work under ISRO sponsored project, 'Thermostructural Analysis of Heated Launch Vehicle Structures’ during August 1994 to December 1996. He was also employed at IIT Bombay as Senior Research Engineer and worked during December 1996 to May 1998 after completing his doctor research work from IIT Kharagpur in ADA Sponsored Project, 'Aeroservoelastic Stability and Response Studies for LCA'. He subsequently moved to Aeronautical Development Agency, Bangalore as scientist and worked for over six and half years in various positions such as Scientist/Engineer ‘C’ and ‘D’. He joined department of Aerospace Engineering, IIT Kharagpur as Assistant Professor on October 2004. He has been promoted to Associate Professor and Professor in the years 2007 and 2014 respectively. He is currently holding the professor post in the Department of Aerospace Engineering, IIT Kharagpur. He has published over 60 international journal papers, over 60 national and international conference papers, over 50 project reports, handled several research projects sponsored by ARDB, ADA, DST, ISRO, etc. of worth a few crores. So far 9 research students have obtained their PhD degree under his supervision. Currently 13 research students are pursuing their doctoral research work under his supervision. He has guided over 70 M.Tech students for their Master’s Projects and over 50 B.Tech students for their B.Tech Projects. His primary research areas are analysis of composite structures under static and dynamic loadings employing various higher-order shear deformation theories, damage modelling of isotropic and composite materials, smart structures, aeroelasticity/aeroservoelasticity, structural health monitoring, etc.

Keynote Speaker

New higher order inverse trigonometric quasi 3-D theories for nonlinear dynamic analyses of a laminated composite plate

Bhrigu Nath Singh

Department of Aerospace Engineering, Indian Institute of Technology Kharagpur



Abstract

The productive progression and regularly expanding development of composite materials in different weight saving designs, utilized in many industries like aerospace, mechanical, civil, etc., the laminated composite plates have gained significant attention due to its high strength to weight ratio, high fatigue life, high corrosion resistance, its design tailoring properties etc. The bend extensional and bend twist coupling properties of these structures have led to their extensive use in aerospace industries. However, these laminated composites are having inadequate strength in shear because of its low transverse shear modulus. Hence, it is imperative to study the consequences of shear deformation on the laminate composite structures by developing an efficient mathematical model. The classical laminated plate theory (CLPT), developed by Kirchhoff neglects the effect of shear deformation. Thus, it is inadequate to predict the response of the structures efficiently. So, it was further modified by Ressiner-Mindlin by including the effect of shear deformation and considering the cross-section remains straight after deformation by loss of its perpendicularity. This consideration led to constant transverse shear stress distribution across the thickness of the plate, which is the violation of 3-D elasticity solution. Hence, to overcome the above limitations and to analyze the accurate solution by first order shear deformation theory (FSDT), a shear correction factor was used which depends on factors like boundary condition, lay-up, fiber orientations etc.

In order to avoid the drawbacks of CLPT and FSDT, another theory was proposed namely higher order shear deformation theory (HSDT) by many researchers, which shows a non-linear distribution of transverse shear stresses along the thickness. These HSDTs can be classified into two categories depending on the type of higher order shear strain shape functions i.e. polynomial type or non-polynomial type. The use of polynomial type, more than third degree polynomial is a computationally expensive task. So, many non-polynomial shear deformation theories, i.e. based on different nonpolynomial shear strain functions of type trigonometric, hyperbolic, exponential etc. have been developed to apprehend the response of structures adequately and efficiently. Further, the effect of dynamic loading conditions are more severe than the static loading, during the operation of the structures. Thus, there is a necessity to develop a numerical tool to capture the dynamic behavior of the laminated composite structures accurately and efficiently. However, in many instances the structures may not behave linearly. In that case, the consideration of the effect of nonlinearity is the only alternative left for the engineer. Hence, in this paper, a simple quasi 3-D theory based on inverse trigonometric shear strain function has been proposed to encapsulate the dynamic response of the structures and implemented for the dynamic analyses. The results are very promising from the accuracy point of view.

Bio-sketch

Professor Bhrigu Nath Singh is a HAL Chair Professor and Former Head of Aerospace Engineering Department and currently Dean (HR) and Officiating Registrar at the Indian Institute of Technology Kharagpur, India. Prof. Singh has more than 26 years of teaching and/or research experience in the institute of national importance in India and abroad as well. Professor Singh is working in the area of Aerospace Structures, Stress, composite structures, 3D textile composites, FGM, damaged mechanics, aeroealsticity and its uncertainty quantification. Prof. Singh has developed several stochastic and deterministic mathematical models and its applications in the structural components made of laminated and smart composites and 3D textile composites. Issues and concerns related to nonlinear problems in both random and deterministic environments in composite structures have been handled by Prof. Singh. Prof. Singh is a fellow of IE (India) and Associate Editor of Sadhana Journal of Springer publication and Editor of International Journal of Aerospace System Engineering since 2017 and 2016 respectively. Prof. Singh was a member of Aerospace Resource Panel of the DRDO, New Delhi, India at national level during 2013-16. Prof. Singh has so far published 138 papers in the Journals of repute such as AIAA J, ASME J, ASCE J, JSV, CM, CS, IJMS, etc and more than 90 papers mostly in refereed International Conference proceedings. He has organised so far four international conferences and edited their proceedings (ICACEM 2007, 2010, 2014 & 2017) in which about 250 delegates from India and abroad attended. Prof. has been organising Secretary of ICTACEM 2010, Conference Chair of ICTACEM 2014 and Technical Chair of ICTACEM 2017 respectively. His h-index and i-index are 33 and 82 respectively in Google scholar (GS), h-index is 27 in Scopus and citations more than 3084 in GS, which reflects the hard work and devotion towards research in the field of aerospace engineering and other fields. He has guided 14 Ph.D., 55 M. Tech and several B. Tech students so far and he is currently supervising 10 Ph.D. students. Prof. Singh has put forth his knowledge and ideas in some of the best Journals handling in the areas of aerospace (composite) and mechanical engineering as reviewer such as AIAA J, ASME J, JSV, IJMS, CS, etc. Prof. Singh has been deeply involved in the research and development and carried out many such projects. He has been reviewers of many projects on the research and development of DST and DRDO. Prof. Singh has been also involved as Principal Investigator (PI) in handling several sponsored research projects of DRDO, ISRO and development projects of DST valued about Rs. 4.5 Crores so far. Prof. Singh has been very instrumental in strengthening research facilities of the department as a faculty and Head of the Department. Prof Singh has also imparted training of research personnel in different fields of Aerospace Science & Technology and he was also involved in several high value amounting about Rs. 91 Lakhs academic trainings programme for HAL design and management trainees and one for Korean students as coordinator and principal coordinator. He is listed among Top researchers in the area of uncertainty quantification in composite structures and Composite Structures in Scopus/Web of Science and Aerospace Structures. His several research articles have been listed as most cited papers in the reputed Journals such as Finite elements in Analysis & Design and International Journal of Mechanical Sciences. Prof. Singh is well known for grooming under graduate and post graduate students to carry out research and build up their career through research route. Several students of Prof. Singh are working as faculty members in best Institutions/organisations including three in IITs, two in NITs, two in ISRO, 4 in DRDO, etc and also in very good companies of world.

Keynote Speaker

An engineering topology optimization method for large-scale complex structures and its improvement

Hai Huang

School of Astronautics, Beihang University



Abstract

The structural topology optimization is to find the best component layout in a structural system. Theoretically, it could be realized by removing unnecessary components from a ground structure by solving a mixed-variable mathematical programming problem, which includes the integer variables (α=0/1) to represent the absence or presence of each component. Because of existing the 0/1 variables, the topology optimization problems are hardly solved efficiently and only small-scale truss topology problems were implemented before. To avoid discrete or intrger variables, most of the current works are based on the concept of continuum topology optimization, which is to seek optimal material distribution in a design space of a structure. The continuum topology optimization methods usually have a good efficiency, however, they still suffer many shortages such as hardly handling stress constraints, post processing required for results, etc. More severe, the FE models used in continuum topology optimization could not match the requirements and characteristics of engineering structures that usually composed of discrete components like trusses, beams, plates, or a combination of them.

Aiming at above problems, This presentation firstly introduces an engineering method[1] which is an our just completed work, and the method can simultaneous topology and size optimization for complex structures that may contain bars, beams, shells, and their combinations. Further studies on the proposed method are conducted in this work. The key reasons what the proposed method can efficiently solve the traditional topology problems are analyzed. Since a special approximate formula (1-dimensional case see fig.1) which contains both continuous and integer variables is established, the topology optimization problems including 0/1 variables could be also solved through series of approximate problems as similar as structural size optimization. Meanwhile the defects that could result in errors of the final optimization design by introducing the special approximate formula are also investigated. Then an improvement on the method is proposed by introducing additional design points. Numerical examples including topology-size optimization for typical truss and shell-stiffeners combined structures showed the effectiveness and efficient of the improvement for the original method.

Fig.1 the proposed approximate formula in 1-dimensional case

Bio-sketch

Dr. Hai Huang, Professor, Chair, Dept. Of Spacecraft & Launch Vehicle Technology, School of Astronautics, Beihang University; editorial board members of Chinese Journal of Aeronautics and review editor of international journal Structural and Multidisciplinary Optimization. He got his bachelor, master and Ph.D degrees in 1983, 1986 and 1990 respectively, all from Beihang University. He ever worked as a post-doctoral fellow on composite joint strength and design in the Wichta State University, USA. His research areas are concept design of spacecraft, system and structural optimization, structural control as well as their applications. During the past 10 years he led his team to endeavor in applying the proposed structural optimization theories and the software to aerospace engineering, which include the practical designs of some Chinese satellite programs such as the meteorology satellites FY-3 and FY-4 that are well operating on orbit. These works are great helpful to reduce the spacecraft structural mass. In the research area of structural/mechanical vibration control, he developed several kinds of vibration isolation and test devices. The devices are used for vilifications or conducting the ground test aiming to space applications. Dr. Huang dedicated lots of his efforts in aerospace education. He is, as a team leader, working on a student micro satellite program that well combines theoretical study with engineering practice. The work is supported by APSCO SSS project.