P. Gandhi

P. Gandhi
Structural Engineering Research Centre · Fatigue & Fracture Laboratory

B.E. (Civil), M. Sc. Engg. (Structures)

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80
Publications
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568
Citations

Publications

Publications (80)
Article
The primary objective of this manuscript is to verify the LBB criterion, by carrying out fatigue crack growth (FCG) and fracture tests on SA 312 Type 304LN stainless steel pipes having a part-through crack in the circumferential direction. FCG tests were carried out on pipe specimens under constant amplitude loading in bending till the crack became...
Chapter
Pipelines used for transporting oil, gas and other petroleum products operate under pressure resulting in formation of fatigue cracks leading to the risk of catastrophic failure of piping systems. It is important to evaluate the performance of in-service pipelines with crack-like defects and assessment of remaining life will be useful for repair, r...
Article
In service, the piping components (pipes/elbows) are subjected to different operational loadings such as thermal stress, internal pressure, self-weight, external loading from soil movement, flow induced vibration, vortex induced vibrations and third party damage. Structural integrity assessment of these piping components under postulated accidental...
Article
Fracture studies were carried out on bi-metallic pipe weld joints of 324 mm outer diameter having crack at different regions of weld in the circumferential direction. The bi-metallic pipe weld joints were made of low alloy steel (ferritic) and stainless steel (austenitic) materials. Welding consumable used was nickel-based alloy. The initial notch...
Article
The use of GFRP bars in concrete structures has emerged as an alternative to conventional RC due to the corrosion of steel in aggressive environments. Although many studies were reported on concrete beams reinforced with GFRP bars, still the full potentiality of GFRP reinforced concrete is yet to be known. This study reports experimental, analytica...
Article
The level-3 Leak-Before-Break (LBB) assessment of nuclear piping system is based on simplified fracture mechanics calculations. A postulated through-wall circumferential crack is shown to be stable even under extreme loading conditions. An important aspect of this fracture assessment, which is generally not considered, is the reduction in load at t...
Article
Fracture resistance of 316LN SS base and welded straight pipes with circumferential through-wall cracks has been evaluated. The pipe J-R curves have been determined using existing experimental methods and analytical expressions available in literature. The J-R curves of 88.9 mm OD pipe and pipe welds have been compared with the J-R curves obtained...
Article
Fracture studies were carried out on narrow gap welded SA 312 Type 304LN stainless steel straight pipes having circumferential through-wall notch in the weld. Totally six specimens were tested; one specimen was subjected to monotonic loading and the remaining five specimens were subjected to quasi-cyclic loading. Under quasi-cyclic loading, one spe...
Article
Full-text available
Fatigue crack growth (FCG) experiments were carried out on Eccentrically-loaded Single Edge notch Tension [ESE(T)] specimens made of SA 333 Gr. 6 and SA 516 Gr. 70 steels under demineralized water and 3.5% NaCl aqueous environments. The corrosion process was accelerated by increasing the corrosion current, using an external current source and the e...
Chapter
Bi-metallic welded joints are necessary in pressurized and boiling water reactors where heavy section low alloy carbon steel components are connected to stainless steel primary piping systems. The behaviour of such bi-metallic weld joints is very difficult to understand, and very limited experimental data are available in the literature on the frac...
Article
Fracture studies were carried out on 170 mm OD welded straight pipes having circumferential through-wall crack in the weld under quasi-cyclic loading. The specimens were made of Type 304 LN stainless steel and welded using conventional Shielded Metal Arc (SMA) welding or Narrow Gap (NG) welding. The specimens were subjected to different amplitudes...
Article
Elbows are one type of components widely used in various industrial applications in conventional and nuclear power generating plants, chemical processing plants and petroleum refineries. Due to the complexities of geometric structure, elbows are one of the piping components that are prone to failure in the piping system of nuclear power plants (NPP...
Article
Fatigue life of fillet welded cruciform joints with load-carrying welds conforming to Constructional Detail 26 (Detail Category 52) of IS 800: 2007 and made of IS 2062 Gr. E 300 steel plates of two different thicknesses was evaluated. The joints were formed by Manual Metal Arc welding conforming to IS 9595: 2003. The studies were carried out at var...
Conference Paper
Corrosion is a crucial problem in steel reinforcement which deteriorates the material when it reacts with the environment. Glass Fibre Reinforced Plastic (GFRP) rebar has emerged as a promising alternative to conventional steel reinforcement with excellent results in terms of corrosion resistance. GFRP rebars are usually composed of glass fibres re...
Article
Full-text available
Long welded rails are being introduced for railway tracks extensively in India for increasing the speed of the rolling stock and for better travel comfort. Thermit welding and flash butt welding are being used for welding of rails in many countries. A number of firms are using these two techniques for welding of rails in India. Fatigue fracture of...
Conference Paper
This paper presents the results of fatigue tests conducted on typical welded and bolted connections made of IS 2062: 2011 steel and conforming to selected Constructional Details categorised in IS 800: 2007. The connection types include: Longitudinal and transverse butt welded connections, fillet welded cruciform connections with load-carrying and n...
Conference Paper
The use of Glass Fibre Reinforced Plastic (GFRP) rebars as a potential replacement for steel reinforcement has raised quite a bit of controversy among the professionals and engineers engaged in the construction industry. Divergent views have beenopined by the professionals for its usage in civil engineering structures. Even though, the GFRP rebar h...
Conference Paper
Full-text available
Corrosion is a crucial problem in steel reinforcement which deteriorates the material when it reacts with the environment. Glass Fibre Reinforced Plastic (GFRP) rebar emerged as a promising alternative to traditional steel reinforcement with excellent results in terms of corrosion resistance. Its advantages include high longitudinal strength and te...
Article
Full-text available
Ratcheting studies were carried out on Type 304LN stainless steel elbows, by applying steady internal pressure and cyclic bending. The elbows were of 168 mm nominal outer diameter and the average thickness varied from 14.7 mm to 15.1 mm The elbows filled with water were pressurized between 27.6 MPa and 39.2 MPa. Cyclic bending load, under the openi...
Article
Full-text available
With an objective of understanding the cyclic fracture, fatigue crack growth and ratcheting behaviour of Type 304LN stainless steel piping components used in primary heat transport system of nuclear power plants, subjected to various operational, loading and environmental conditions, experimental studies were carried out on totally 36 straight pipe...
Conference Paper
Full-text available
The objective of the present study is to understand the fatigue crack growth behavior and validate analytical procedures for austenitic stainless steel and carbon steel pipes, pipe welds and elbows. The study involved fatigue tests on actual components and specimens. The Paris law has been used for the prediction of fatigue crack growth life. Paris...
Article
Pipe bends or elbows are commonly used components for nuclear power plant piping system. In service, these piping components are subjected to internal pressure in addition to bending loads and the internal pressure is known to have a significant effect on the load carrying capacity of these components. Hence, a systematic study was carried out to i...
Article
Ratcheting is a phenomenon which leads to reduction in fatigue life of a structural component by loss of ductility due to cycle by cycle accumulation of plastic strain. Ratcheting occurs in a structure subjected to a combination of steady/sustained and cyclic loads such that the material response is in inelastic region. Ratcheting studies were carr...
Article
The design of Nuclear Power Plant piping is based on Leak-Before-Break (LBB) design philosophy. The integrity of cracked nuclear piping system in LBB is often examined from conventional fracture mechanics. Conventionally the fracture analysis is performed by assuming infinite compliance of the piping system, which means that the stiffening effect o...
Article
The objective of the present study is to understand the fatigue crack growth behavior in austenitic stainless steel pipes and pipe welds by carrying out analysis/predictions and experiments. The Paris law has been used for the prediction of fatigue crack growth life. To carry out the analysis, Paris constants have been determined for pipe (base) an...
Article
This paper presents the results of fatigue tests conducted on simple constructional details categorised in IS 800:2007. The specimens were made of IS 2062 steel. The tests were carried out at various values of maximum stress which were decided as a percentage of yield strength of the material. The S-N data obtained for these connections are compare...
Article
In level-3 Leak-Before-Break (LBB) analysis, stability of a postulated through-wall circumferential crack is demonstrated by simplified fracture mechanics calculations. Detailed experimental studies, conducted by the authors, have revealed that the conventional assessment procedure used to demonstrate LBB is too conservative. There is a large facto...
Conference Paper
The objective of the present study is to understand the fatigue crack growth behavior in austenitic stainless steel and carbon steel pipes and pipe welds by carrying out analysis/predictions and experiments. The Paris law has been used for the prediction of fatigue crack growth life. To carry out the analysis, Paris constants have been determined f...
Conference Paper
Full-text available
Fatigue-Ratcheting' is a phenomenon which leads to reduction in fatigue life of a structural component by loss of ductility due to cycle-by-cycle accumulation of plastic strain. One real-life example of a situation with fatigue ratcheting possibility is piping of power plants subjected to internal pressure and large amplitude cyclic bending during...
Article
Full-text available
'Fatigue Ratcheting' is a phenomenon which leads to reduction in fatigue life of a structural component by loss of ductility due to cycle-by-cycle accumulation of plastic strain. One real-life example of a situation with fatigue ratcheting possibility is piping of power plants subjected to internal pressure (primary load) and cyclic bending (second...
Article
The determination of depth profile of vertical fatigue cracks generated in thick cruciform samples using an ultrasonic phased array is investigated in this paper. The cracks were formed by conducting fatigue fracture test on two mild steel cruciform specimens of 135 mm thickness: one under room temperature and the other under subzero temperature (-...
Article
Fracture behaviour of piping components used in pressurised heavy water reactors of nuclear power plants are of great importance to ensure safety and integrity against the extreme load conditions. Fracture mechanics approach predicts crack growth behaviour under normal operating conditions and failure load under accidental conditions. Leak-Before-B...
Article
This paper describes the results of fatigue studies on carbon steel piping materials and components of Indian Pressurized Heavy Water Reactors (PHWRs). The piping components include pipes and elbows, of outer diameter 219mm, 324mm and 406mm, made of carbon steel (SA333 Gr.6 grade) material. Tests on actual pipes and elbows with part through notch w...
Article
Steel offshore structures are widely used for production and processing of oil and natural gas from offshore areas. In addition to regular sea waves, these structures are subjected to natural hazards like cyclones and hurricanes and also to severe hydrodynamic forces during the monsoon periods. In addition to these natural hazards, these structures...
Article
Studies have been carried out on carbon steel pipes to demonstrate the leak before break design criterion and validate the analytical procedures. Fatigue crack initiation, fatigue crack growth rate and fracture resistance behaviour of the pipes have been experimentally and analytically evaluated. The tests have been carried out on pipes of outer di...
Article
Welded steel tubular structures commonly used for offshore platforms are susceptible to fatigue failure due to stress concentration at welded joints and environmental loading which is cyclic in nature. Offshore structures contain flaws ranging from microscopic material defects to macroscopic geometric imperfections, due to fabrication and construct...
Article
Full-text available
The use of internal ring stiffeners in offshore steel jacket platforms is a subject of controversy because of their peculiar failure pattern, observed in several tests in the early 1980s. It is estimated that at least 2,000 internally ring-stiffened steel tubular joints are in service in the North Sea. Despite the fact that internal ring stiffeners...
Article
Piping components such as tees and elbows used in the primary heat transport system of power plants undergo stress fluctuations due to operational and extreme loading conditions. Crack initiation and through-thickness lives of piping components are of primary concern in the justification of Leak Before Break methodology for the design of piping com...
Article
Steel jacket platforms are widely used for production and processing of oil from offshore fields. Tubular joints of these structures are susceptible to fatigue or corrosion fatigue cracking due to cyclic wave action, stress concentration, and corrosive environment. The submerged part of the structure is cathodically protected against corrosion by f...
Article
Hollow sections are generally either circular-to-circular (CCHS) or rectangular-to-rectangular (RRHS). Structures with circular braces and rectangular chords (CRHS) may have advantages in certain applications, combining a simple joint geometry for fabrication and relatively lower stress concentration factors (SCFs). Seven different CRHS joints were...
Article
Full-text available
Welded steel tubular structures commonly used for offshore platforms are susceptible to fatigue failure due to stress con· centration at welded joints and environmental loading which is cyclic in nature. Internally ring stiffened steel tubular joints are found to be efficient in reducing stress concentration and improving ultimate and fatigue stren...
Article
Welded tubular structures ate widely used for offshore platforms. In India, there are more than 120 offshore platforms in the Bombay High region, all of which are jacket-type structures consisting of welded tubular members. The tubular joints of these structures are subjected to stress concentration, which because of the increased hot-spot stresses...

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