Department of Mechanical Engineering

&ldquo;IIT Jodhpur is committed to impart quality education to facilitate the creation of qualified, competent and responsible human resources to meet the emerging technological challenges of the world. It is working towards creating an equitable learning platform that is positive, accessible and effective in the face of the modern societal and scientific advancements.

Flexibility in curriculum, in all its academic programs, encompassing elements of teaching, research, creativity, innovation and entrepreneurship is the most unique feature of IIT Jodhpur. The Department of Science and Technology (DST), under the National Mission on Cyber Physical Systems, has identified IIT Jodhpur as a Technology &amp; Innovation Hub in the area of Augmented Reality and Virtual Reality. The institute has also been nominated as the coordinator for the Jodhpur City and Knowledge Cluster by the Office of Principal Scientific Adviser, Government of India.

The sprawling 852-acre IIT Jodhpur campus is a majestic tribute to the deep-rooted diverse cultural heritage of the region. The campus is an architectural masterpiece, which is slated to become an international exemplar of sustainability with net-zero energy, and advanced water and waste management strategies.&rdquo;

IIT Jodhpur

Bio-materials which would interact with human cells are chosen based on the issues of compatibility. The materials preferred in bone repair or replacements at load bearing sites require particular attention to strength and rigidity, which should match the native tissue. Any kind of mismatch between native bone and implant would lead to adverse results such as improper bone growth leading to reoperation. Further, the bone has varied mechanical properties at different sections and is anisotropic. Present work is a manifestation of Polyetheretherketone (PEEK) and Hydroxyapatite(HAp) bio-composite mechanical properties. The composites are prepared by mixing in a ball mill followed by compression moulding, sintering and heat treatment. © 2017 Trans Tech Publications, Switzerland.

World University root node

Materials Science Forum

Evaluation of mechanical properties of PEEK HAp bio-composite used in load bearing bone implants

In the present investigation, a systematic study has been undertaken with regard to the effects of tempering time on room temperature mechanical properties of P91 (X10CrMoVNNB9-1) steel. Samples cut from P91 (X10CrMoVNNB9-1) industrial pipe were normalized at 1040 ℃ for 40 min and then tempered at 760 ℃ for different tempering times starting from 2 h to 8 h. Detailed analysis of microstructure, particle size, inter-particle spacing, and secondary phase carbide particles of the tempered samples was conducted by secondary electron microscopy technique. Optical microscopy was also utilized to characterize the tempered samples and for the measurement of grain size. In order to reveal the various phases formed during tempering of P91 (X10CrMoVNNB9-1) steel, X-ray diffraction was carried out. To study the fracture surface morphology of tensile tested and impact tested specimen field-emission scanning electron microscopy was carried out. The effect of tempering time on the microstructural parameters revealed an increase in grain size up to 4 h of tempering and then decreased because of recrystallization. The coarsening of secondary phase carbide particles M23C6 was revealed with an increase in tempering time. As a consequence, yield strength, hardness, and ultimate tensile strength were observed to decrease with increase in the tempering time. However, a drastic change was observed in the yield strength, ultimate tensile strength, and toughness after tempering for 6 h. From the present study, it was concluded that optimum combination of yield stress, ultimate tensile strength, hardness, and toughness obtained after tempering at 760 ℃ for 6 h. © 2016, © IMechE 2016.

Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering

Evolution of phases during tempering of P91 steel at 760℃ for varying tempering time and their effect on microstructure and mechanical properties

The modified 9Cr-1Mo (P91) and 9Cr- 0.5Mo- 1.8W (P92) steel used in fast breeder reactor is exposed to irradiation during service which severely affects the dynamic fracture resistance by increasing the ductile to brittle transition temperature (DBTT). Thus, even at room temperature, the steel can become brittle and prone to cracking. In the present investigation, to elucidate the influence of low temperature on the DBTT, Charpy toughness test was performed on creep strength enhanced ferritic P91 and P92 steel. Lower DBTT was observed for the P92 steel as compared to P91 steel. To find the mode of fracture, the fractured Charpy toughness specimens were investigated using a field electron scanning electron microscope (FESEM). The fracture surface revealed the brittle mode of fracture at a lower temperature for both the steels while the mixed mode of fracture was noticed at room temperature and above. © 2017 Elsevier Ltd

Engineering Failure Analysis

A comparative study of ductile-brittle transition behavior and fractography of P91 and P92 steel

In the present research work, creep strength enhanced ferritic/martensitic P91 steel was subjected to varying normalizing (950–1150 °C) and tempering temperature (730–800 °C). The varying normalizing and tempering temperature effect on microstructure evolution (precipitate size and their distribution and grain size) and microhardness were performed. The heat treatment consequences on microstructure evolution revealed an increase in grain size, and decrease in fraction area of precipitates, with increase in normalizing temperature. The grain size was found to be decreased with increase in tempering temperature while fraction area of precipitates and precipitate diameter increased. For microstructure characterization, optical microscope and field emission scanning electron microscope were utilized. The microhardness was found to be increased with increase in normalizing temperature while it decreased with increase in tempering temperature. © 2017 The Indian Institute of Metals - IIM

Transactions of the Indian Institute of Metals

Nano-size Particle Evolution During Heat Treatment of P91 Steel and Their Effect on Micro Hardness

In present research work, the as-received cast & forged (C&F) P91 steel was subjected to the creep test at temperature of 620 °C and 650 °C for applied stress of 120 MPa. The room temperature tensile test was conducted after normalizing and tempering (N&T) treatment of the ruptured creep specimen. The standard tensile-test specimen was prepared from the gauge section of creep ruptured specimen. The N&T treatment was performed to restore the microstructure and mechanical properties of virgin P91 steel (N&T P91 steel). The microstructure of creep fractured specimen in ruptured state and N&T condition were characterized by using field-emission scanning electron microscope (FE-SEM) with energy dispersive X-ray spectroscopy (EDS). The fracture surface morphology of crept specimen and the tensile tested specimen was also studied. The effect of prior creep deformation on the mechanical strength was more significant in the sample with longer creep rupture life. © 2017

Effect of creep phenomena on room-temperature tensile properties of cast &amp; forged P91 steel

This study investigates the shock transformation in an underexpanded jet in a confined duct when the jet total pressure is increased. Experimental study reveals that the Mach reflection (MR) in the fully underexpanded jet transforms to a regular reflection (RR) at a certain jet total pressure. It is observed that neither the incident shock angle nor the upstream Mach number varies during the MR-RR shock transformation. This is in contradiction to the classical MR-RR transformations in internal flow over wedges and in underexpanded open jets. This transformation is found to be a total pressure variation induced transformation, which is a new kind of shock transformation. The present study also reveals that the critical jet total pressures for MR-RR and RR-MR transformations are not the same when the primary pressure is increasing and decreasing, suggesting a hysteresis in the shock transformations. © 2017 Cambridge University Press.

Journal of Fluid Mechanics

Shock transformation and hysteresis in underexpanded confined jets

Solar food drying is a complex heat and mass transfer phenomena which depend on a number of drying process-dependent parameters such as operating conditions and characteristics of the food product to be dried. The variation in these parameters significantly affects the overall performance of the dryer system. Since commercial growth and acceptance of any solar dryer system momentously depend on its performance guarantee, the development of a standard methodology for their thermal testing has become necessary. The standard testing method not only provides better performance management of the dryer system but allows the manufacturers to achieve competitive efficiency and good product quality by comparing the available designs. In this chapter, an extensive review of solar dryer performance evaluation has been carried out. Furthermore, the chapter describes the existing testing procedures for the most common designs of solar dryers and the related practices used in the measurement, evaluation, and description of overall performance, including a variety of food product dried in scientific investigations. © 2017, Springer Nature Singapore Pte Ltd.

Green Energy and Technology

Thermal testing methods for solar dryers

Shakers are widely used to simulate the vibrations for academic research, as well as for product testing. Thus, there is a significant necessity to study them in detail. Amongst the different types of shakers being used, the electrodynamic shaker is by far the most versatile. However, limited work has been done with regard to their integrated electro-mechanical modelling. In this work, we have developed a mobility-based lumped parameter model of an electrodynamic shaker and also a method to measure its various electrical and mechanical parameters using non-destructive and easy to use methods. Towards meeting the latter goal, we conducted experiments to determine the shaker table’s impedance and transfer functions, and used these data for subsequent parameter extraction. Such a model was later validated experimentally. Finally, we predicted the response of the shaker under loaded and unloaded conditions, and confirmed their validity through actual experimental data. © The Author(s) 2017.

Fulltext

Journal of Low Frequency Noise Vibration and Active Control

Lumped parameter modelling and methodology for extraction of model parameters for an electrodynamic shaker

Journal of Aircraft

Flight dynamics of helicopter under steady maneuver: Interesting observations

The work presents the study on flow boiling crisis in helical coils at low pressure with water as working medium. Published correlations of critical heat flux in helical coils are collated. The characteristics of boiling crisis in helical coils are studied. The experiments are performed with six helical coils made of SS 304 tubes having inner diameters varying from 6 to 10 mm. The coil diameter to the tube diameter ratio ranges from 14 to 58. The critical heat flux data are collected in complete saturated region for the quality range of 0–1. The wall temperature distribution is measured in the axial direction using infrared thermal imaging technique. The results concluded that, the wall temperature in inner half surface is higher than outer half surface of helical coils. Increase in mass flux increases the critical heat flux. Critical heat flux decreases with increase in quality. For the same quality, the critical heat flux decreases with increase in tube diameter and coil diameter. In a high quality region, the critical heat flux in helical coils is higher than vertical straight tubes. A correlation is suggested for critical heat flux in helical coils. © 2016 Elsevier Ltd