Department Of Civil Engineering

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Forces in Mechanics

Fatigue in a class of viscoelastic solids

This study evaluates and compares two major solutions used to mitigate the problem of delay of public transport buses at signalized intersections in urban arterials. The solutions considered are to implement bus signal priority (BSP) at intersections and to provide dedicated bus lanes (DBL). Comparison of performance is done in terms of travel time. Study site selected is a 5 km stretch in the IT corridor in Chennai for the DBL and with four intersections in that corridor for the BSP. Only the southbound movement is considered for the analysis. To evaluate the selected strategies, the study site was simulated in VISSIM, which is a micro-simulation software. Road, traffic, and control details from field were used as input, and a calibrated network was created. Using that, four scenarios were studied: 1. base condition with fixed time signals and no dedicated lane, 2. fixed time signal with DBL, 3. BSP without dedicated lane, and 4. BSP and DBL. Conditional Green Extension and Red Truncation priority strategies using Visual Vehicle Actuated Programming (VisVAP) from VISSIM were used for the BSP implementation. For dedicated bus lane condition, the mode preference was altered for the southbound movement links and the bus movement was allowed only in the left-most lane, which was kept as DBL. Results showed the bus signal priority having maximum impact in terms of reduction in total travel time. In the case of dedicated bus lane condition, travel time reduced effectively for bus mode, but with an increase in travel time of other modes. © 2023, Transportation Research Group of India.

World University root node

Lecture Notes in Civil Engineering

Evaluation of Bus Signal Priority and Dedicated Bus Lane for Efficiency Improvement

Petroleum industries are large water consumers and generate a lot of wastewater at various stages of industrial operations. Wastewater from the petroleum industries contain recalcitrant pollutants such as hydrocarbons that are present in high concentrations, dissolved solids and sulfur compounds that can pose potential environmental threat. Bioelectrochemical systems (BESs) are known to be sustainable processes to treat the various kinds of wastewaters such as petroleum wastewater, while simultaneously generating the bioelectricity and value-added chemicals. This review focuses on various applications of BESs such as microbial fuel cells (MFC), microbial electrolysis cells (MEC), and microbial desalination cells (MDC) using diverse types of wastewaters (petroleum sludge, produced water, formation water, and petroleum refinery wastewater) from the petroleum industries. Overall, a hybrid type BES with hydrocarbon wastewater achieved a 98% of columbic efficiency, 96.5% of chemical oxygen demand (COD), 99% of phenanthrene, 94% of pyrene and 80% of TDS removal which are superior to single and dual chamber BES performances. The review also compares the existing biological processes with BESs in terms of the treatment of hydrocarbons and process sustainability. Treatment efficiency of petroleum wastes via the BES can be further improved by integrating the biological and electrochemical processes to develop a sustainable approach to bio-refinery route. © 2022 Elsevier Ltd

Fulltext

Fuel

Sustainable bioelectrochemical systems for bioenergy generation via waste treatment from petroleum industries

Blast wave simulators (BWS) are shock tubes capable of generating shockwaves with Friedlander profile (typical profile observed during free field explosion).They have primary importance in blast-related research.The pressure–time profile parameters, such as peak overpressure, positive time duration, and decay coefficient of the shockwave, depend on the shock tube parameters (STPs) such as driver length, driven length, and burst pressure.We can generate shockwaves with the desired pressure–time profile by effectively tuning the STP.This study experimentally investigates the effect of driver length on the pressure–time profile of a shockwave generated by a blastwave simulator.Increasing the driver length increases the positive phase duration and peak overpressure at all probe locations.Also, it increases Friedlander profile formation distance.Further, a finite element model for shock tube is developed in ABAQUS/Explicit and the numerical results are compared with the experimental observations.The developed numerical model can predict the observed pressure–time profile with reasonable accuracy, so that it can be used for further parametric studies in the design of blast wave simulators. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

Investigations with Blast Wave Simulators

Gas hydrate sediments are considered as one of the potential sources of unconventional energy because of their high energy density and presence of abundant subsurface reserves in order to meet the rising global energy demand. Methane gas hydrate sediments generally occur naturally in permafrost regions and in deep-sea continental shelves where the water depth is more than 500 m below the mean sea level. These deep-water sediments have a high concentration of methane hydrates. Efficiently extracting (safe and economical) these unconventional energies will help in mitigating the energy demand of a country. The current study focuses on predicting the geo-mechanical response of gas hydrates using elastic-plastic constitutive relations and compare with the existing elemental experimental results. From the numerical integration of these advanced models, it is observed that the HISS-MH model could simulate realistic material response under triaxial conditions. Further, an investigation is also carried out to understand the effect of hydrate saturation and Over Consolidation Ratio (OCR) on the geo-mechanical response. There is an increase in stiffness, peak stress, stress dilatancy ratio and softening response with the increase in hydrate saturation. The response is due to the enhancement of cementation between soil particles with hydrate saturation. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

Department of Applied Mechanics

Numerical Study on the Effect of Hydrate Saturation on the Geo-Mechanical Behavior of Gas Hydrate Sediments

Periodic structures are found to exhibit band gaps which are frequency bandwidths where structural vibrations are absorbed. In this paper, meta-structures are built by dynamically linking oscillators in a periodic pattern, which are referred to as dynamically linked element grade oscillators or D-LEGOs. The location of the band gaps is numerically determined for a one-dimensional D-LEGO. The unit cell for the D-LEGO structure is considered to be made up of two longitudinal bar elements of different properties. For such a structure, the frequency response functions (FRFs) of a single unit cell are used to estimate the band gaps of a periodic-lattice structure by adapting the Bloch wave theory. Alternatively, the FRF of the multi-unit cell is determined using FRF-based substructuring (FBS) approach. The band gaps resulting from these two approaches are compared and verified. © 2023, The Society for Experimental Mechanics, Inc.

Conference Proceedings of the Society for Experimental Mechanics Series

Band Gap Estimation of D-LEGO Meta-structures Using FRF-Based Substructuring and Bloch Wave Theory

For industrial storage applications, selective pallet racks are used, which are assembled from perforated slender cold-formed steel sections. The frame of pallet racks comprises braced frames in the cross-aisle direction and moment frames with semi-rigid connections in the down-aisle direction. The European code EN15512:2009 is normally used for the design of such racks. The use of linear elastic analysis for the design is a common practice, which EN15512 permits. However, the linear elastic analysis becomes inadequate for tall racks – typically over 15 m, because of second-order effects. The second-order effects may be significant in the down-aisle direction as the height of the pallet rack increases. Codes of practice, including IS:800 uses a frame stability parameter to assess whether the second-order analysis is required or not. The aim of this study is to investigate the second-order effects on the stability of such racks in the down-aisle direction and quantify the effects with respect to the height of the racks. Frames have been modelled in MASTAN2, and analytical studies have been done on frames of various heights. The results indicate that second-order analysis, including the effect of semi-rigidity of the connections, significantly amplifies the drifts and design forces and hence, cannot be ignored in the design of such racks. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

Structural Integrity

Evaluation of Second-Order Effects in Cold-Formed Steel Pallet Racks

Typically, the strength gain mechanism in RCCP, especially at initial days (aggregate interlocking), is different from its counterparts and thus requires accurate proportioning of aggregates with good workability properties. In this study, the various fundamental parameters of RCCP mix design, viz. aggregate gradation, vebe consistency, water-cement ratio (W/C), and aggregate-cement ratio (A/C), are studied critically through the particle packing approach. The IRC: SP-68 blending approach is compared with the modified Andreasson model. The parameters considered for gradation optimization are packing density, consistency, maximum dry density (MDD), and compressive strength. The results indicated the effectiveness of IRC gradation in terms of higher packing density (1–4%), MDD (0.1–2.7%), and compressive strength (12–67%) over the modified Andreasson model. The finding from this analysis suggests that designing RCCP mixes with the A/C between 5.7 and 6 and W/C in the range of 0.36–0.40 could achieve better consistency and strength properties. © 2023, Transportation Research Group of India.

Systematic Approach to Optimize Roller-Compacted Concrete Pavements Mixes Through Particle Packing Method

Estimating delays at different road segments and intersections is a primary step in any traffic management system. Delay along a path can be estimated using sensors such as Global Positioning System (GPS) sensors, Camera sensors, Wi-Fi sensors and On-Board Diagnostics (OBD) data of the vehicle. The former three techniques have been used for some time now, but the latter one has not been explored much, especially for estimating delay. The accuracy of methodologies using OBD, Wi-Fi and Camera was calculated using data from GPS as ground truth. Results obtained showed the performance of all these methods to be comparable. Choice of the right sensor may depend on various other factors such as cost, weather factors, accuracy, range, etc. Sometimes more than one sensor needs to be used for the desired results. This paper explores three techniques in more detail and summarizes the advantages and disadvantages of each one of them in various scenarios. © 2023, Transportation Research Group of India.

Comparison of Delay Estimation Techniques for Advanced Traffic Management

This study explores the use of On-Board Diagnostics (OBD) data in the analysis and prediction of vehicle dynamics. Though various data sources are available for traffic data collection, these conventional approaches may not work for the complex traffic system in India, with its heterogeneity and lack of lane discipline. On-board units such as GPS and OBD are some devices, which perform independent of the traffic conditions. This study focuses on the use of OBD data along with GPS data for individual vehicle trajectory prediction. A machine learning tool, namely Long–Short-Term Memory (LSTM) model is employed and the prediction of speed and bearing for the next 1 s is done. Results obtained showed the OBD as a potential source of data that can be used for various real-time and offline applications. © 2023, Transportation Research Group of India.