Damage detection of multi-storeyed shear structure using sparse and noisy modal data

S.K. Panigrahi,S. Chakraverty,S.K. Bhattacharyya 국제구조공학회 2015 Smart Structures and Systems, An International Jou Vol.15 No.5

In the present paper, a method for identifying damage in a multi storeyed shear building structure is presented using minimum number of modal parameters of the structure. A damage at any level of the structure may lead to a major failure if the damage is not attended at appropriate time. Hence an early detection of damage is essential. The proposed identification methodology requires experimentally determined sparse modal data of any particular mode as input to detect the location and extent of damage in the structure. Here, the first natural frequency and corresponding partial mode shape values are used as input to the model and results are compared by changing the sensor placement locations at different floors to conclude the best location of sensors for accurate damage identification. Initially experimental data are simulated numerically by solving eigen value problem of the damaged structure with inclusion of random noise on the vibration characteristics. Reliability of the procedure has been demonstrated through a few examples of multi storeyed shear structure with different damage scenarios and various noise levels. Validation of the methodology has also been done using dynamic data obtained through experiment conducted on a laboratory scale steel structure.

Inner harbour wave agitation using boussinesq wave model

Panigrahi, Jitendra K.,Padhy, C.P.,Murty, A.S.N. The Society of Naval Architects of Korea 2015 International Journal of Naval Architecture and Oc Vol.7 No.1

Short crested waves play an important role for planning and design of harbours. In this context a numerical simulation is carried out to evaluate wave tranquility inside a real harbour located in east coast of India. The annual offshore wave climate proximity to harbour site is established using Wave Model (WAM) hindcast wave data. The deep water waves are transformed to harbour front using a Near Shore spectral Wave model (NSW). A directional analysis is carried out to determine the probable incident wave directions towards the harbour. Most critical threshold wave height and wave period is chosen for normal operating conditions using exceedence probability analysis. Irregular random waves from various directions are generated confirming to Pierson Moskowitz spectrum at 20m water depth. Wave incident into inner harbor through harbor entrance is performed using Boussinesq Wave model (BW). Wave disturbance experienced inside the harbour and at various berths are analysed. The paper discusses the progresses took place in short wave modeling and it demonstrates application of wave climate for the evaluation of harbor tranquility using various types of wave models.

Prediction of product parameters of fly ash cement bricks using two dimensional orthogonal polynomials in the regression analysis

S. Chakraverty,Himani Saini,S. K. Panigrahi 사단법인 한국계산역학회 2008 Computers and Concrete, An International Journal Vol.5 No.5

This paper focuses on the application of two dimensional orthogonal polynomials in the regression analysis for the relationship of product parameters viz. compressive strength, bulk density and water absorption of fly ash cement bricks with other process parameters such as percentages of fly ash, sand and cement. The method has been validated by linear and non-linear two parameter regression models. The use of two dimensional orthogonal system makes the analysis computationally efficient, simple and straight forward. Corresponding co-efficient of determination and F-test are also reported to show the efficacy and reliability of the relationships. By applying the evolved relationships, the product parameters of fly ash cement bricks may be approximated for the use in construction sectors.

Ballistic impact analyses of triangular corrugated plates filled with foam core

Panigrahi, S.K.,Das, Kallola Techno-Press 2016 Advances in computational design Vol.1 No.2

The usage of sandwich structure is extensively increasing in lightweight protective structures due to its low density and other useful properties. Sandwich panels made of metal sheets with unfilled cellular cores are found to exhibit lower deflections by comparing to an equivalent monolithic plate of same metal and similar mass per unit density. However, the process of localized impact on solid structures involving plastic deformation, high strain rates, temperature effect, material erosion, etc. does not hold effectively as that of monolithic plate. In present work, the applications of the sandwich plate with corrugated core have been extended to develop optimized lightweight armour using foam as medium of its core by explicit finite element analysis (FEA). The mechanisms of hardened steel projectile penetration of aluminum corrugated sandwich panels filled with foams have been numerically investigated by finite element analysis (FEA). A comparative study is done for the triangular corrugated sandwich plate filled with polymeric foam and metallic foam with different densities in order to achieve the optimum penetration resistance to ballistic impact. Corrugated sandwich plates filled with metallic foams are found to be superior when compared to the polymeric one. The optimized results are then compared with that of equivalent solid and unfilled cores structure to observe the effectiveness of foam-filled corrugated sandwich plate which provides an effective resistance to ballistic response. The novel structure can be the alternative to solid aluminum plate in the applications of light weight protection system.

Inner harbour wave agitation using boussinesq wave model

Jitendra K. Panigrahi,C.P. Padhy,A.S.N. Murty 대한조선학회 2015 International Journal of Naval Architecture and Oc Vol.7 No.1

Short crested waves play an important role for planning and design of harbours. In this context a numerical simulation is carried out to evaluate wave tranquility inside a real harbour located in east coast of India. The annual offshore wave climate proximity to harbour site is established using Wave Model (WAM) hindcast wave data. The deep water waves are transformed to harbour front using a Near Shore spectral Wave model (NSW). A directional analysis is carried out to determine the probable incident wave directions towards the harbour. Most critical threshold wave height and wave period is chosen for normal operating conditions using exceedence probability analysis. Irregular random waves from various directions are generated confirming to Pierson Moskowitz spectrum at 20m water depth. Wave incident into inner harbor through harbor entrance is performed using Boussinesq Wave model (BW). Wave disturbance experienced inside the harbour and at various berths are analysed. The paper discusses the progresses took place in short wave modeling and it demonstrates application of wave climate for the evaluation of harbor tranquility using various types of wave models.

An improved envelope detection method using particle swarm optimisation for rolling element bearing fault diagnosis

Sunil Tyagi,S.K. Panigrahi 한국CDE학회 2017 Journal of computational design and engineering Vol.4 No.4

Traditionally Envelope Detection (ED) is implemented for detection of rolling element bearing faults by extracting the envelope of band-passed vibration signal and thereafter taking its Fourier transform. The performance of ED is highly sensitive to the envelope window (i.e. central frequency and bandwidth of the passband). This paper employs Particle Swarm Optimisation (PSO) to select the most optimum envelope window to band pass the vibration signals emanating from rotating driveline that was run in normal and with faults induced rolling element bearings. The envelopes of band-passed signals were extracted with the help of Hilbert Transform. The performance of ED whose envelope window was optimised by PSO to identify various commonly occurring bearing faults such as bearing with Outer Race Fault (ORF), Inner Race Fault (IRF) and Rolling Element Fault (REF) were checked under varying load conditions. The performance of ‘ED enhanced by PSO’ was also checked with increase in the severity of defect. It was shown that the improved ED method is successfully able to identify all types of bearing faults under different load conditions. It was shown that the by selecting envelope window by PSO makes ED especially useful to identify bearing faults at the incipient stage of defect. It was also shown by presenting comparative performance that by optimising the envelope window by PSO the performance of ED gets significantly enhanced in comparison to the traditional ED method for bearing fault diagnosis.

Improvement in mechanical properties of sintered zirconia (3% yttria stabilized) by glass infiltration

Balakrishnan, A.,Panigrahi, B. B.,Chu, M.-C.,Kim, T. N.,Yoon, K.-J.,Cho, S.-J. MRS MATERIALS RESEARCH SOCIETY 2007 Journal of materials research Vol.22 No.9

Development of gear fault diagnosis architecture for combat aircraft engine

Rajdeep De,S.K. Panigrahi Techno-Press 2023 Advances in computational design Vol.8 No.3

The gear drive of a combat aircraft engine is responsible for power transmission to the different accessories necessary for the engine's operation. Incorrect power transmission can occur due to the presence of failure modes in the gears like bending fatigue, pitting, adhesive wear, scuffing, abrasive wear and polished wear etc. Fault diagnosis of the gear drive is necessary to get an early indication of failure of the gears. The present research is to develop an algorithm using different vibration signal processing techniques on industrial vibration acquisition systems to establish gear fault diagnosis architecture. The signal processing techniques have been used to extract various feature vectors in the development of the fault diagnosis architecture. An open-source dataset of other gear fault conditions is used to validate the developed architecture. The results is a basis for development of artificial intelligence based expert systems for gear fault diagnosis of a combat aircraft engine.

Phase formation and dielectric study of Bi doped BaTi0.75Zr0.25O3 ceramic

T. Badapanda,S.K. Rout,S. Panigrahi,T.P. Sinha 한국물리학회 2009 Current Applied Physics Vol.9 No.4

Perovskite types Ba1-xBi2x/3Ti0.75Zr0.25O3 (with x = 0.0, 0.025, 0.05) ceramics have been prepared through solid state reaction route. The room temperature XRD study suggests that all the compositions have single phase cubic symmetry with space group Pm-3m. Temperature dependent dielectric studies of the ceramics have been investigated in the frequency range of 50 Hz–1 MHz. The densities of the samples are determined using Archimedes’ principle and found to be ~98% of X-ray density. The dielectric study revealed diffuse phase transition of second order. A broad dielectric anomaly coupled with the shift of dielectric maxima toward a higher temperature with increasing frequency indicates the relaxor-type behavior in the ceramics. The diffusivity increases with increase in Bi contents in the studied composition range. The transition temperature decreases with increase in Bi contents due to the decrease in grain size. Perovskite types Ba1-xBi2x/3Ti0.75Zr0.25O3 (with x = 0.0, 0.025, 0.05) ceramics have been prepared through solid state reaction route. The room temperature XRD study suggests that all the compositions have single phase cubic symmetry with space group Pm-3m. Temperature dependent dielectric studies of the ceramics have been investigated in the frequency range of 50 Hz–1 MHz. The densities of the samples are determined using Archimedes’ principle and found to be ~98% of X-ray density. The dielectric study revealed diffuse phase transition of second order. A broad dielectric anomaly coupled with the shift of dielectric maxima toward a higher temperature with increasing frequency indicates the relaxor-type behavior in the ceramics. The diffusivity increases with increase in Bi contents in the studied composition range. The transition temperature decreases with increase in Bi contents due to the decrease in grain size.

Dielectric Behavior of Yttrium doped Barium-zirconium-titanate Ceramics

T. Badapanda,S. Panigrahi,T. P. Sinha,우성일,S. K. Rout 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.2

The ferroelectric behavior of the yttrium-doped barium-zirconium-titanate perovskite ceramics Ba1−xY2x/3Ti.75Zr0.25O3 (with x = 0.0, 0.01, 0. 025, 0.05) has been studied. The room temperature X-ray diffraition study suggests that all the compositions have a single-phase cubic symmetry with space group Pm-3m The temperature dependent dielectric constant of the ceramics was investigated in the frequency range from 50 Hz to 1 MHz. The density of the samples was determined using Archimedes’ principle and was found to be ~98% of the X-ray density. A broad dielectric anomaly coupled with a shift of the dielectric maximum towards a higher temperature with increasing frequency indicates relaxor-type behavior in the ceramics With increasing in yttrium content, the Curie temperature decreased, except for x = 0.01 where the Curie temperature increased. The relative permittivity decreased and broadened with increasing yttrium content.