Effect of delamination on vibration characteristic of smart laminated composite plate

Ganesh Shankar,Jayant Prakash Varun,P.K.Mahato 항공우주시스템공학회 2019 항공우주시스템공학회지 Vol.13 No.4

This study is concerned with a numerical analysis based on the finite element method to describe the effect of midplane delamination in smart laminated composite plate structures. A new finite element model for centrally located delamination and healthy section was developed and coded in Matlab. The transient analysis of delaminated composite plate with integrated Active Fiber Composite (AFC) was investigated in the present article. The formulation of the governing equation was based on the minimum total potential energy approach. The Newmark time integration technique was employed to solve the differential equations. A parametric study on the effects of boundary conditions and AFC patch location, in presence of delamination on the laminated plate were studied.

Design optimization of a 2-DOF parallel kinematic machine based on natural frequency

S. Shankar Ganesh,A. B. Koteswara Rao 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.2

In this paper, kinematics, workspace, and dynamic analysis of a two degree of freedom (2-DOF) translational parallel robot are carried out. The mechanism of the 2-DOF translational parallel robot consists of four links. Links 1 and 2 consist of three revolute joints and link 3 and 4 consist of three revolute joints and one prismatic joint. These four links are attached to the end effector. The inverse kinematics analysis is carried out to find the joint positions for a particular position of the moving platform. Using stiffness and dynamic mass matrices, the natural frequencies of the parallel kinematic machine (PKM) are obtained. Since the first natural frequency is responsible for higher vibrations, the first natural frequency is considered as performance measure of the PKM i.e. global natural frequency index (GNFI). Using GNFI as the objective, the optimal dimensions of the PKM are obtained.

Multi-objective optimization of a 3-DOF translational parallel kinematic machine

S. Shankar Ganesh,A. B. Koteswara Rao,Sanjay Darvekar 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.12

In this paper, stiffness modelling and analysis of a typical 3-DOF parallel kinematic machine (PKM) that provides translational motion along X, Y and Z axes is presented. The mechanism consists of three limbs each having an arm and a forearm with prismatic-revoluterevolute- revolute joints (PRRR). The joint arrangement is in such a way that the moving or tool platform maintains same orientation in the entire workspace. Through inverse kinematics, the joint angles for a given position of tool platform necessary for the stiffness modelling and analysis are obtained. The stiffness modelling is based on the compliance matrices of arm and forearm of each limb. Typical non-dimensional performance indices, namely, workspace volume index (WVI), global translational stiffness index (GTSI), and global rotational stiffness index (GRSI), are introduced and used to study the influence of dimensions. Attempts are also made to find the optimal dimensions of the translational PKM using multi-objective optimization based on the genetic algorithms (MOGA) in MATLAB. The methodology presented and the results obtained are useful for predicting the performance capability of the PKM under study.

Inverse dynamics of a 3-DOF translational parallel kinematic machine

S. Shankar Ganesh,A. B. Koteswara Rao 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.11

In this paper, kinematics and dynamics modeling of a typical 3-Degree of freedom (DOF) translational Parallel kinematic machine(PKM) is carried out. The kinematic structure of PKM consists of three limbs, connecting the base and the tool platform. Each limb consistsof an arm and a forearm with joints Prismatic-revolute-revolute-revolute (PRRR). The arrangement of joints are in such a way thatthe tool platform will have pure translational motion along the Cartesian axes. Inverse kinematic relations that are necessary to find theslider positions and joint angles for a given position of tool platform are derived. The dynamics model is then derived based on Naturalorhogonal complement (NOC). The inverse dynamics equations presented are used to compute actuator forces. The actuator forces usingNOC are validated with those obtained based on Lagrangian method. The effect of slider, arm, and forearm inertia on the actuator forcesis studied to know whether to neglect the arm and forearm inertias while computing the actuator forces for PKM. Finally, an attempt ismade to find the optimal location of a circular trajectory using Genetic algorithms (GA) with minimization of Grand total actuator force(GTAF) as objective function.

Exergoeconomic Analysis of a Novel Zeotropic Mixture Power System

N. Shankar Ganesh,Uma Maheswari,Tangellapalli Srinivas,B. V. Reddy 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.9 No.1

A parametric investigation of a novel ammonia water mixture power generation system is performed in this study. The overall performance and feasibility of the system of the proposed system are assessed from thermoeconomic, conventional exergy and advanced exergy perspectives. For better heat recovery in the existing medium-temperature heat recovery Kalina system, auxiliary solar heater is considered in the proposed design to improve the overall performance in terms of energy and exergy. The system performance parameters investigated include cycle efficiency, net output, total product cost rate, exergoeconomic factor and total exergy destruction rate. The simulation of the energy and exergy analysis was performed using Python coding. In this respect, the parametric investigation revealed that the cycle efficiency, net output, total product cost rate, exergoeconomic factor and total exergy destruction rate of the system at optimized conditions are 15.5%, 280 kW, 136 $/GJ, 66% and 120 kW, respectively. The irreversibilities of each component and overall system were evaluated and it was found that the turbine accounts for the highest exergy destruction among all components, contributing nearly 13% of the total exergy destruction of the system. Advanced exergy analysis was also performed that involved characterizing the exergy destruction as endogenous, exogenous, avoidable, and unavoidable, leading to specific recommendations for improving the performance of the system. Conventional exergy analysis suggests that the turbine, HE 4 , and separator are the components typically identified for improvement. The advanced exergy analysis in this study, however, indicated that the separator should be the primary focused for performance improvement, followed by the HE 4 and turbine.

Strontium in Al–Si–Mg Alloy: A Review

M. R. Sai Ganesh,Nikhil Reghunath,M. J.Levin,Adarsh Prasad,Sanapala Doondi,Karthik V. Shankar 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.1

The present article reviews the development of cast aluminium alloy with highlights on improvement in the morphological,mechanical, tribological, and ageing properties of Sr modifed Al–Si and Al–Si–Mg alloys. Aluminium and its alloys fndapplication in the automobile and aviation industries. The main objective of utilizing aluminium alloys for structural application, manufacturing of pistons and engine block for automobile industries is its lightweight and low density. However, thelow hardness of these alloys results in a high wear rate. The main factor that afects the properties of aluminium alloys isits microstructure, morphological behaviour, size of the grain and phase distribution. The morphological modifcation forthese alloys is done through diferent processing techniques like casting, heat treatment, solutionising, and alloying elementaddition which augments the mechanical, corrosion, and tribological behaviour of these alloys. Of the alloying elementadditions Sr has proved to a very efective modifer for the alloy, and hence the method of modifcation was studied in detail. The unwanted efects especially porosity, being one of the main factors for failure of components, were investigated andmethods to reduce it according to many researchers were included. Reinforcing the aluminium matrix with ceramic particlesand surface modifcation also enhances the properties of aluminium alloys. The current article reviews the recent techniquesto augment the microstructure, value of hardness, tensile properties, tribological properties, and corrosion behaviour of castAl–Si and Al–Si–Mg alloys by the addition of strontium. Moreover, this review also focuses on the future scope of thesealuminium alloys for structural application in automobile and lightweight industries.

Polyetheretherketone Versus Titanium Cages for Posterior Lumbar Interbody Fusion: Meta-Analysis and Review of the Literature

Elie Massaad,Nida Fatima,Ali Kiapour,Muhamed Hadzipasic,Ganesh M. Shankar,John H. Shin 대한척추신경외과학회 2020 Neurospine Vol.17 No.1

Objective: Lumbar fusion with implantation of interbody cage is a common procedure for treatment of lumbar degenerative disease. This study aims to compare the fusion and subsidence rates of titanium (Ti) versus polyetheretherketone (PEEK) interbody cages after posterior lumbar interbody fusion and investigate the effect of clinical and radiological outcomes following fusion on patient-reported outcomes. Methods: A systematic search strategy of 4 electronic databases (MEDLINE, Embase, Web of Science, and Cochrane) was conducted using different MeSH (medical subject headings) terms until January 2020. Pooled odds ratios (ORs) with 95% confidence intervals (CI) were calculated using fixed and random-effect models based upon the heterogeneity (I2) to estimate the association between interbody cages and the measured outcomes. Results: A total of 1,094 patients from 11 studies were reviewed. The final analysis included 421 patients (38.5%) who had lumbar surgery using a Ti and/or a Ti-coated interbody cage and 673 patient (61.5%) who had lumbar surgery using a PEEK cage. Overall, PEEK interbody devices were associated with a significantly lower fusion rate compared with Ti interbody devices (OR, 0.62; 95% CI, 0.41–0.93; p=0.02). There was no difference in subsidence rates between Ti and PEEK groups (OR, 0.91; 95% CI, 0.54–1.52; p=0.71). Also, there were no statistically significant differences in visual analogue scale (VAS)-low back pain (p=0.14) and Japanese Orthopedic Association scale (p=0.86) between the 2 groups. However, the PEEK group had lower odds of leg pain after surgery compared to the Ti group (OR [VAS-leg], 0.61; 95% CI, 0.28–0.94; p=0.003). Conclusion: Ti and Ti-coated PEEK cages used for posterior lumbar interbody fusion are associated with similar rates of subsidence, but a higher rate of fusion compared to PEEK interbody cages. Randomized controlled trials are needed to better assess the effect of cage materials and potential factors that could influence the outcomes of interbody lumbar fusion.

Predictive Analytics in Spine Oncology Research: First Steps, Limitations, and Future Directions

Elie Massaad,Nida Fatima,Muhamed Hadzipasic,Christopher Alvarez-Breckenridge,Ganesh M. Shankar,John H. Shin 대한척추신경외과학회 2019 Neurospine Vol.16 No.4

The potential of big data analytics to improve the quality of care for patients with spine tumors is significant. At this moment, the application of big data analytics to oncology and spine surgery is at a nascent stage. As such, efforts are underway to advance data-driven oncologic care, improve patient outcomes, and guide clinical decision making. This is both relevant and critical in the practice of spine oncology as clinical decision making is often made in isolation looking at select variables deemed relevant by the physician. With rapidly evolving therapeutics in surgery, radiation, interventional radiology, and oncology, there is a need to better develop decision-making algorithms utilizing the vast data available for each patient. The challenges and limitations inherent to big data analyses are presented with an eye towards future directions.

CORRIGENDUM: Correction of Figure 2: Polyetheretherketone Versus Titanium Cages for Posterior Lumbar Interbody Fusion: Meta-Analysis and Review of the Literature

Elie Massaad,Nida Fatima,Ali Kiapour,Muhamed Hadzipasic,Ganesh M. Shankar,John H. Shin 대한척추신경외과학회 2020 Neurospine Vol.17 No.2

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Association of Spinal Alignment Correction With Patient-Reported Outcomes in Adult Cervical Deformity: Review of the Literature

Elie Massaad,Muhamed Hadzipasic,Ali Kiapour,Asad M. Lak,Ganesh Shankar,Hasan A. Zaidi,Stuart H. Hershman,John H. Shin 대한척추신경외과학회 2021 Neurospine Vol.18 No.3

Objective: Adult cervical deformity (ACD) is a debilitating spinal condition that causes significant pain, neurologic dysfunction, and functional impairment. Surgery is often performed to correct cervical alignment, but the optimal amount of correction required to improve patient-reported outcomes (PROs) are not yet well-defined. Methods: A review of the literature was performed and Fisher z-transformation (Zr) was used to pool the correlation coefficients between alignment parameters and PROs. The strength of correlation was defined according to the following: poor (0<r≤0.3), fair (0.3<r≤0.5), moderate (0.5<r≤0.8), and strong (0.8<r≤1). Results: Increased C2–7 sagittal vertical axis was fairly associated with increased Neck Disability Index (NDI) (pooled Zr=0.31; 95% confidence interval [CI], -0.03 to 0.58). Changes in T1 slope minus cervical lordosis poorly correlated with NDI (pooled Zr=-0.04; 95% CI, -0.23 to 0.30). Increased C7–S1 was poorly associated with worse EuroQoL 5-Dimension (pooled Zr=-0.22; 95% CI, -0.36 to -0.06). Correction of horizontal gaze did not correlate with legacy metrics. Modified Japanese Orthopedic Association correlated with C2-slope, C7–S1, and C2–S1. Conclusion: Spinal alignment parameters variably correlated with improved health-related quality of life and myelopathy after corrective surgery for ACD. Further studies evaluating legacy PROs, Patient-Reported Outcomes Measurement System, and ACD specific instruments are needed for further validation.