i-manager's Journal on Structural Engineering (JSTE)


Volume 1 Issue 1 March - May 2012

Research Paper

Optimum Stacking Sequence Design of a Blended Laminated Wing Structure using Permutation Genetic Algorithms

D. Liu* , V.V. Toropov**, D.C. Barton***, M. Zhou****
*-** School of Civil Engineering, University of Leeds, UK.
*** School of Mechanical Engineering, University of Leeds, UK.
**** Altair Engineering Inc., McCabe Way, Suite 100, Irvine, CA, USA.
Liu, D., Toropov, V.V., Barton, D.C., and Zhou, M. (2012). Optimum Stacking Sequence Design of a Blended Laminated Wing Structure using Permutation Genetic Algorithms. i-manager’s Journal on Structural Engineering, 1(1), 1-11. https://doi.org/10.26634/jste.1.1.1700

Abstract

The smeared stiffness-based method is examined for finding the best stacking sequence of laminated composite wing structures in a bi-level optimization process with blending and manufacturing constraints. At the global level optimization, the numbers of plies of the pre-defined angles (0, 90, 45 and -45 degrees) are design variables, buckling, strain and ply angle percentages are constraints and the weight is the objective function. Since the permutation Genetic Algorithm (permGA) operator changes the stacking sequence without changing the composition of the laminate in the composite laminate optimization problem, a permGA is an ideal tool to shuffle the plies to minimize the difference between the values of computed lamination parameters for a current stack and the ones coming from the top level, for which the lamination parameters are zeros due to homogeneity throughout the thickness of the laminate assumed in the top level optimization. This is embedded into an easy and efficient blending procedure applied at this level to achieve the global ply continuity. This multi-stage local optimization by permGAs is demonstrated by the optimization of the root part of a generic aircraft wing structure.

Research Paper

Removal of Chromium using Natural Adsorbent

Sagar M. Shinde* , Shridhar S. Kumbhar**
* Assistant Professor, Department of Civil Engineering, R.I.T. Rajaramnagar.
** Associate Professor, Department of Civil Engineering, R.I.T. Rajaramnagar.
Shinde, S.M., and Kumbar, S.S. (2012). Removal of Chromium using Natural Adsorbent. i-manager’s Journal on Structural Engineering, 1(1), 12-25. https://doi.org/10.26634/jste.1.1.1701

Abstract

In this present study, adsorption of Cr (VI) ions on tamarind tree bark adsorbent has been studied through using batch adsorption techniques. The main objectives of this study are to 1) investigate the chromium adsorption from aqueous solution by tamarind tree bark, 2) study the influence of pH, contact time, adsorbent dose, particle size and initial chromium concentration on adsorption process and 3) determine appropriate adsorption isotherm and kinetics parameters of Cr (VI) adsorption on tamarind tree bark. The various parameter’s were determined with the help of synthetic chromium sample and by using electroplating industrial wastewater sample, the parameters adsorbent dose, contact time and particle size were determined. The results show that higher Cr (VI) adsorption was observed at lower pH, and maximum Cr (VI) removal 97% obtained at pH value 1.0 with 30 minutes contact time, adsorbent dose 3.75g/l of particle size 150µ and 5mg/l initial Cr (VI) concentration. The adsorption of Cr (VI) by tamarind tree bark powder decreased at the higher initial chromium concentration. The adsorption of Cr (VI) by tamarind tree bark powder increased with increase in adsorbent dose and decrease in size of adsorbent. The obtained results showed that the adsorption of Cr (VI) by tamarind tree bark follows Freundlich isotherm. The results indicate that tamarind tree bark can be employed as a low cost alternative to commercial adsorbents in the removal of Cr (VI) from wastewater.

Research Paper

Behavior of 22m Two Tiered Geogrid Reinforced Soil Wall

Ankesh Shrivastava* , D. Kishan**
* Assistant Professor, Civil Engineering Department, Sati Vidisha.
** Associate Professor, Civil Engineering Department, Manit Bhopal.
Shrivastava, A., and Kishan, D. (2012). Behavior of 22m Two Tiered Geogrid Reinforced Soil Wall. i-manager’s Journal on Structural Engineering, 1(1), 26-33. https://doi.org/10.26634/jste.1.1.1702

Abstract

Two types of 22m Two Tiered and 44m Four Tiered high geogrid reinforced soil walls with same kinds of concrete block wall facing were constructed in Vijayawada Andhra Pradesh in which 22m high vertical reinforced soil wall with concrete block wall facing has been started and using for the transportation purpose. From the beginning of the 22m reinforced wall construction stage, wall displacement or strain of the geogrid, earth pressure, settlement of the foundation ground, etc. were measured for a long period of time. The long term behavior of the geogrid reinforced soil walls was evaluated based on these measurements and observations. This paper present a case history illustrate the use of finite-element procedure as a design aid for the design and analysis of 22m two tiered soil wall by software PLAXIS 8.2. The finite-element analysis provides relevant information on the mechanical behavior that was otherwise difficult to obtain from the limit-equilibrium based current design approaches.

Research Paper

Finite Element Analysis of Composite Cylindrical Shells with and without Cutouts

B. Siva Konda Reddy* , CH. Srikanth**, G. Sandeep Kumar***
* Department of Civil Engineering, JNTUH College of Engineering, Hyderabad, A.P, India.
** Department of Civil Engineering, Smaskruthi College of Engineering & Technology, Hyderabad, A.P, India.
*** Strucural Division, L&T, New Delhi, India.
Reddy, B.S.K., Srikanth, C., and Kumar, G.S. (2012). Finite Element Analysis of Composite Cylindrical Shells with and without Cutouts. i-manager’s Journal on Structural Engineering, 1(1), 34-38. https://doi.org/10.26634/jste.1.1.1703

Abstract

Laminated composite thin cylindrical shells are most widely used structural forms in Aerospace and Missile applications. These structures may experience axial compression loads in their longevity and yield to buckling. Furthermore, these structures usually have disruptions, such as cutouts, which may have adverse effects on their stability and  buckling loads of laminated cylinders can strongly depend on the stacking sequence & number of layers in a laminate. This paper investigates the effect of stacking, number of layers and size & positioning of cutouts on bucking load of a laminated cylindrical shell. ANSYS software is been used for analysis of cylindrical shells.

Practice Paper

Seismic Analysis and the Influence of Zone Factor of a Multi Storey Hospital Building – a Case Study

K. Subramanian* , M. Velayutham**
* Professor & Head, Department of Civil Engineering, Coimbatore Institute of Technology, Coimbatore.
** PhD candidate, Anna University of Technology, Coimbatore.
Subramanian, K., and Velayutham, M. (2012). Seismic Analysis and the Influence of Zone Factor of a Multi Storey Hospital Building – a Case Study. i-manager’s Journal on Structural Engineering, 1(1), 39-47. https://doi.org/10.26634/jste.1.1.1704

Abstract

Earthquake on 26th January 2001 in Gujarat clearly demonstrated the earthquake vulnerability of India. Almost more than 60% of our land is vulnerable to earthquake of magnitude more than 7. This leads to the professionals to carry out the research on seismic forces that influence on the structures. This paper presents a detailed case study of an upcoming Ten Storey Hospital building analyzed in ETABS using Response Spectrum analysis of IS 1893 (Part1):2002. The proposed structural system for the hospital building consists of conventional beam, column and slab system with lift walls and walls around staircase acting as shear wall. Lateral Stability is provided by shear walls and columns. The upcoming building is proposed to construct in the Zone III region. Importance factor of 1.5 is considered for the structure considering its functionality. The case study discuss on the influence of various zone factors and the codal provisions, when the same building to be located in different regions. Ductile systems are taken in the study, where inelastic analysis procedures effectively account for several sources of force reduction. The earthquake ground acceleration in each direction is given as a digitized response-spectrum curve of pseudo- spectral acceleration response versus period of the structure. The peak response quantities such as member forces, displacements, storey forces, storey shears and base reactions shall be combined as per Complete Quadratic Combination method. The accidental eccentricity is given as direct input in all floor diaphragms. The dynamic analysis results such as modal participating mass ratios, response spectrum base reaction, storey shears, storey displacements and storey drifts are discussed in detail. Animated results of the displacement due to all modes along with their respective time period are displayed for more understanding of the structural behavior. First and Second modes are found to be in translation and third mode is of torsional mode, which is an acceptable solution to proceed with detailed design.