Additional Information:
Teaching Experience:
(1) Assistant Professor of Civil Engineering, Indian Institute of Technology Roorkee, Roorkee, Uttaranchal, India from 29th June 2005 till date
(2) Assistant Professor of Civil Engineering, Birla Institute of Technology and Science (BITS), Pilani, Rajasthan, India from 20th July, 2004-13th May, 2005.
(3) Teaching Assistant for Engineering Drawing and Computer Graphics courses to the first year undergraduates for six semesters (3 years) from 1995-1999 in Indian Institutes of Technology Kharagpur, India
Subjects taught-
Mechanics of Solids,
Engineering Drawing and Computer Graphics,
Theory of Elasticity and Plasticity
Structural Dynamics
Design of Steel Structures
Computational skill :
Computer operating environment : DOS, UNIX, WINDOWS, NT WORKSTATIONS
Computer languages known : FORTRAN, BASIC, C++
Computer systems : DEC-ALPHA-4000, ORIGIN-200 of SILICON
GRAPHICS, PC’s – COMPAQ GATEWAY
Softwares known : ANSYS, NISA, MATLAB, FEMTools
[Ddeveloped his own finite element and model updating software including specialized programs for experimental modal analysis and optimization, such as gradient based methods and genetic algorithm.]
Experimental skill :
Familiar with vibration testing, including full scale modal testing using digital data acquisition and analysis system. Used the SIGLAB system of DSP Technology Inc, which uses MATLAB. Used some more Modal Analysis softwares as well. Experienced in actual field static and vibration testing of large scale civil engineering structures, using various kind of transducers.
Professional Experience :
Name of the Firm : Hindustan Steelworks Construction Ltd. (A Government of India
Undertaking ), 1, Shakespeare Sarani, Calcutta -700 071, West Bengal,
India
Date of Joining/Leaving : 23rd January,1989/30th September, 1992(3 years, 8 months and 9
days ) [Out of this experience, first one year was as a Management
Trainee in the same post]
Designation : Assistant Divisional Engineer
Place of posting : Vishakhapatnam Steel Project, Andhra Pradesh, India
Details of Work : Construction of industrial buildings, workshops etc; construction of
township as turnkey basis. I was associated with the construction and handing over of country’s most sophisticated integrated steel plant and a township in hilly terrain with scenic beauty.
Cause of leaving : For higher study and research
Research Experience during Ph.D. :
Status and tenure of research : An Institute Research Scholar in the Department of Ocean Engineering & Naval Architecture, Indian Institute of Technology, Kharagpur, India.
[10th January, 1995 – 10th January, 2000. Leading to Ph.D Degree.]
Details of work : System Identification of composite stiffened plates, covering both experimental and numerical studies and their correlations, followed by updating of the numerical model using optimisation.
Teaching assistantship : Effectively involved in assisting in Engineering Drawing and Computer Graphics courses to the first year undergraduates for six semesters
Experimental skill : Conducted experimental modal analysis on Fibre Reinforced Plastics (FRP) plates. This covers fabricating, testing, data acquisition and subsequent analysis.
Post Doctoral Research Experience:
1. India
Status and tenure of research : As a Junior Project Officer in the Department of Ocean Engineering &
Naval Architecture, Indian Institute of Technology, Kharagpur, India. 1st April, 2000 – 25th September, 2000.
Details of work : Development of design rules for the structural design of FRP boats and ships
Sponsoring Agency : Ministry of Surface Transport, India. [Ttemporary project staff in the above mentioned project from 11th January, 2000 to 31st March, 2000 ]
2. Abroad (UK)
Status and tenure of research: As a Research Associate in The Department of Mechanical Engineering, The University of Sheffield, United Kingdom.
[30th October, 2000 – 30th September, 2002]
Details of Work: Non-contact damping of structures using magnetostriction and other mechanisms
Sponsoring Agency : Engineering and Physical Sciences Research Council (EPSRC)
The experimental facilities were supported by Rolls Royce Plc.
3. Abroad (Singapore)
Status and tenure of research : As a Research Fellow in The Department of Civil Engineering, Nanyang Technological University, Singapore [2nd June, 2003 to 4th January, 2004]
Details of Work: Integrated Structural Health Monitoring of Highway Bridges in Singapore
4. Abroad (UK)
Status and tenure of research: As a Post Doctoral Research Associate in The Department of Civil and Structural Engineering, The University of Sheffield, United Kingdom.
[9th February, 2004 to 11th June, 2004]
Details of Work: Investigation of as-built vibration performance and serviceability of precast building floors
Sponsoring Agency : Engineering and Physical Sciences Research Council (EPSRC)
Abstract of Master’s Thesis:
Title: Development of a computer code for linear transient response analysis of space frame structures due to support motion
Linear transient response analysis of a space frame structure due to imposed support motion and imposed initial conditions at the free nodes is carried out in both damped and undamped conditions, using direct time integration of dynamic equation of motion. A specialised software is developed to benefit users dealing with problems related to ground motions of buildings due to earthquakes or vibration of transmission towers due to snapping of conducting cables. The code can take specified displacement, velocity or acceleration in time domain as input.
Abstract of PhD. Thesis:
Title:Estimation of physical parameters of stiffened isotropic and composite plates using finite element model updating
An investigation has been carried out to determine the physical parameters (materials as well as geometry) of stiffened isotropic and composite plates from experimental modal analysis results and finite element modelling using model updating techniques. The problem is formulated as a minimization of the disagreement between experiment and numerical model. Three popular techniques - inverse eigensensitivity method, unconstrained optimization using Levenberg-Marquardt algorithm and genetic algorithm are employed and their performances compared. A full experimental case study is also presented.
Areas of Interest and research work done
My research interests in general are - structural dynamics, vibration testing, model updating and system identification, composite structures and magneto-elastic interaction. I am interested in smart structures application using advanced materials and application of advanced techniques to Engineering.
(1)As a post-doctoral research associate in The University of Sheffield, Department of Civil Engineering, I was briefly associated with research on the vibration serviceability of long span concrete floors and using the finite element model updating methodology as a tool to estimate the existing damping and distributed stiffness of composite floorings and to assess the requirement for structural modification. I was associated with multi-shaker modal testing of a long span car park building in South London- the research is one of the pioneering in this field of study carried out by the research group there.
(2) Integrated Structural Health Monitoring of highway bridges in Singapore:.
I have carried out research on Integrated Structural Health Monitoring of Highway Bridges in Singapore involving vibration testing, analysis, correlation and updating of finite element models of an actual existing bridge. As a major part of the research, suitable modal testing has been conducted on parts of a bridge at various stages of construction to verify the prediction using the finite element model and the model is fine tuned using proper software of model updating. This calibrated model will be later used to simulate bridge response under various complicated external excitations, e.g. earthquake, heavy traffic or sudden change in temperature. Another usefulness of this calibrated model is the detectability of structural changes or damage which will also be investigated in future.
(3) Non-contact damping of structures using magnetism
I have completed a project (2 years) on non-contact damping of structures using magnetism in the Department of Mechanical Engineering, The University of Sheffield, England. The work was very challenging and the Dynamics Research Group there was looking for novel techniques of damping which can supplement the existing methodologies. The ultimate goal was to invent a strain sensitive passive damping mechanism using magnetostrictive materials, such as TERFENOL-D. The project was divided into two parts - change in magnetic field due to stress and use of change in magnetic field for energy dissipation.
The immediate conclusion of the first part of the project however, was negative and till date with the best possible material, it was not possible to create strain sensitive magnetic field of sufficient strength to use it in non-contact dissipation. The work however, speculates the impact of invention of any such future material. This was for the first time a strain sensitive magnetic field generator has been tried.
The second part of the project however was successful and a magneto-elastic damped absorber was designed using viscoelastic damper and permanent magnets and a non-magnetic beam whose motion is to be damped. The system characteristics were generalised for future modelling.
This is the first time a non-contact passive energy dissipation mechanism is studied and applied to beam structure and its application to rotational system is bright. More investigation will be carried out in future. The present results have been published in referred journals.
(4) Finite Element Model Updating of Composite Stiffened Structures
My other research interest is Finite Element Model Updating of Composite Stiffened Structures using Vibration Test data, which was my PhD research topic.
Model updating is all about correcting an approximate finite element model with respect to experimental vibrational data, to produce a more realistic model.
Identification of physical parameters, both geometrical and material parameters of stiffened plate have been attempted, using simulated and real experimental modal data, finite element modelling and optimisation techniques.
The significant findings are - this is the first time structural form is taken into consideration along with material properties and an attempt has been made to estimate the layerwise elastic parameters of composite bare plates from vibration test data. This part has serious limitations in terms of global optimised solutions and this is a major contribution of the work. The present work indicates the feasibility of an updating exercise of stiffened plate identification problem, which are eventually ill posed due to lack of experimental data.
The most significant contribution of this investigation was, a realisation has been achieved that it is better to have a combination of naïve approach (like Genetic Algorithm) and classical approach (such as calculus based gradient approaches) to have the most effective result. GA may be used for quickly locating the error region and later the gradient-based approaches can fine tune the solutions.
Future Research Plan
(1) Finite Element Model Updating using Vibration Test Data of real civil engineering structures, such as building and bridges etc. is the most attractive future research. As the health monitoring of Civil Engineering Structures are becoming more and more relevant from safety point of view, a considerable number of clients are now interested to invest money in accurate determination of their dynamic properties. So far, a conservative approach using existing code of practices was the only mean to achieve this goal. At the most, a limited number of measurements using natural ambient excitation were somehow a better tool to update the existing models/ parameters. But the potential of using actual modal test to at least a large number of Civil Engineering structures is great and may lead to a sea change into the attitude of professionals currently working in this area. This is mainly because of the fact that many clients are interested in large slender structures, with only a few supports. There is little scope of neglecting the contribution of damping from these as it was earlier in case of massive traditional structures. The designers are fast changing their attitude and preferring people having knowledge of structural dynamics to take active role. I feel this can certainly be taken as a long term research topic.
(2) In fact, model updating using finite element modeling and actual testing together can form an alternative solution to predictive maintenance by responsible authorities who are taking care of the important issue of when and how to upgrade a structure to cater to the demand of expanding population. In fact, the model updating technique can be used to quantify the effectiveness of upgradation or improvement of existing ‘healthy’ structures as well as can be used for damage detection.
(3) One of the most misunderstood and less studied topic in model updating is the propagation of error and uncertainty (both experimental and modeling error) through the updating parameters to the finally updated model. I have interest in developing analytical tools to counteract this problem statistically and this certainly is one of my future research plan. A relatively simple composite structure, such as a composite plate can be analyzed and experimented to have a complete study in itself. This can be a very good research.
(4) The magneto-structural interaction is obviously a very interesting topic, but needs huge initial investments in terms of equipments and materials, without which any theoretical study is meaningless. The initiation of this kind of research will largely depend upon the beneficiaries and their willingness to fund such projects.
An idea which has not yet been explored in one discipline is quite common in other! There are many unexplored ideas in a particular branch of science whereas that may be a well known fact to another one and there is no one to bridge the gap!
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