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Empirical relationship for fracture energy in machining processes: a FEM-based investigation with AISI 1045 steel

INTERNATIONAL JOURNAL OF INTERACTIVE DESIGN AND MANUFACTURING - IJIDEM 2024年第4期18卷 2405-2413页

作者： Damahe, Akash Jiyalal Sumesh, C. S. Ramesh, Ajith Amrita Vishwa Vidyapeetham Dept Mech Engn Amrita Sch Engn Coimbatore India

The scarcity of experimental data poses a significant challenge when using FEM in machining processes. Accurately selecting fracture energy is crucial for cutting force optimization, and this study aims to establish an empirical relationship between fracture energy, cutting force, and machining parameters. In this work, turning operations were performed on AISI 1045 steel rods for different combinations of machining parameters and corresponding cutting forces were noted. Then, a detailed FEM model for an orthogonal turning process on AISI 1045 steel with Abaqus/Explicit was developed and the study demonstrates the need to adjust fracture energy for each combination of cutting conditions to accurately match experimental outcomes. The developed numerical model is validated with experimental results and in the validated model fracture energy is varied. The variation of cutting force for different values of fracture energy was plotted for each combination. From the plots, fracture energy corresponding to the experimental cutting force was obtained. Using a multi variable regression method, a relation of fracture energy in terms of machining parameters and cutting force was found. The findings show that the optimal fracture energy value in the model decreases with increasing cutting speed and feed.

关键词： Orthogonal turning Abaqus/Explicit Johnson Cook Fracture energy Cutting force multi variable regression

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A Sensitive Wavebands Identification System for Smart Farming

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Computer Systems Science & Engineering 2022年第10期43卷 245-257页

作者： M.Kavitha M.Sujaritha Department of Computer Science and Engineering Sri Krishna College of Engineering and TechnologyCoimbatore641025India

Sensing the content of macronutrients in the agricultural soil is an essential task in precision *** helps the farmers in the optimal use of *** reduces the cost of food production and also the negative environmentalimpacts on atmosphere and water bodies due to indiscriminate dosageof *** traditional chemical-based laboratory soil analysis methodsdo not serve the purpose as they are hardly suitable for site specific soil ***,the spectral range used in the chemical-based laboratory soil analysismay be of 350-2500 nm,which leads to redundancy and *** sensors based on the discovery of spectral wavebands that respondto soil macronutrient concentrations,on the other hand,is an innovative and successfultechnology since the results are dependable and *** goal of thisarticle is to use a supervised neuro-fuzzy based dimensionality reduction approachin the sensor development process to determine sensitive wavebands of ***,the spectral signatures of the soil are collected inan outdoor environment and mapped with its macronutrient *** thisspectral analysis,the spectral reflectance of 424 wavelengths has been obtainedand these wavelengths are evaluated through combined and individual modesas *** wavelengths are selected in each case by minimizing the fuzzy reflectance assessment *** effectiveness of these selected wavelengthsin each mode is validated by modeling the relation between the reduced reflectancespace and each macronutrient concentration using Partial Least Squares multi variable regression(PLS-MVR)*** of optimal wavebands areidentified and the results are compared with the existing systems.

关键词： Sensitive waveband determination macronutrients feuro-fuzzy based dimensionality reduction partial least squares multi variable regression reflectance

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Modelling the capacity of micropiled-raft foundation rested on soft clayey soil using an artificial neural network approach

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INTERNATIONAL JOURNAL OF GEOTECHNICAL ENGINEERING 2022年第5期16卷 558-573页

作者： Borthakur, Nirmali Das, Manita Natl Inst Technol Silchar Civil Engn Dept Silchar Assam India Siksha O Anusandhan Univ Inst Tech Educ & Res Civil Engn Dept Bhubaneswar Odisha India

Micropiled-raft foundation shows its ability to solve particular type of foundation problem i.e. building of medium height and weight structures over soft deep-seated clayey soil deposit. Potential of artificial neural network method was used in the study for the assessment of capacity of micropiled-raft foundation under a given settlement in soft clayey soil considering the complex non-linear load-settlement behaviour. Experiments were conducted on micropiled-raft foundation constructed with different variables within a soft clayey soil bed in the test pit in field and a database was prepared from load-settlement graphs those were utilized to develop different ANN models. It was observed from the study that Bayesian Regularization algorithm with 90-10% validation model performs the best. Sensitivity analysis was performed to determine the relative significance of different input variables and a neural interpretation diagram was prepared. An empirical equation was proposed with best fit ANN model and an example illustrated.

关键词： Micropiled-raft foundation clayey soil artificial neural network multi variable regression capacity algorithm

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Characterising primary fragment in debris cloud formed by hypervelocity impact of spherical stainless steel projectile on thin steel plate

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INTERNATIONAL JOURNAL OF IMPACT ENGINEERING 2018年第Oct.期120卷 118-125页

作者： Verma, P. N. Dhote, K. D. Armament Res & Dev Estab Dr Homi Bhabha Rd Pune 411021 Maharashtra India

Hypervelocity impact of a projectile on a thin plate generates a debris clouds. Largest chunk (mass) of the projectile material (called primary fragment) in the cloud poses significant ballistic threat to subsequent structure. Primary fragment characteristics (mass, velocity and exit angle) are used in assessing subsequent structure damage potential. Non-dimensional empirical equations are proposed in this paper for estimation of these characteristics. A set of simulations has been carried out using smoothed particle hydrodynamics (SPH) technique of Autodyn. Two stage light gas gun test data has been compared for validation of simulation. Simulation results for spherical projectile made of stainless steel impacting mild steel plate with impact velocity of 2-4 km/s and obliquity of 0 degrees-60 degrees has been analysed. Constants and radicals of the proposed equations are determined by multi variable regression of the simulation data. Comparison of the simulation data with the proposed equations shows a very good fit.

关键词： Hypervelocity impact Primary fragment Thin plate Empirical equation multi variable regression

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Investigation of Hole Size Formation by Steel Sphere Impacting on Thin Plate at Hypervelocity 11th

Investigation of Hole Size Formation by Steel Sphere Impacti...

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11th International Symposium on Plasticity and Impact Mechanics (IMPLAST)

作者： Dhote, K. D. Verma, P. N. Armament Res & Dev Estab Dr Homi Bhabha Rd Pune 411021 Maharashtra India

Protective structures against hypervelocity impact of fragments consists of a thin skin (bumper plate) followed by air gap and main structure. The bumper causes shattering of the fragment and reduces fragment penetration capability to the main structure. Hole size formed in the bumper plate is indicative of damage extent to the main structure and is a direct measure of exposure to new impacts. An extensive study for characterization of hole size in thin aluminium plates due to hypervelocity impacts of aluminium projectiles has been reported in literature. An empirical equation is generally used to estimate the hole size which depends on non-dimensional parameters relating the target and projectile geometry, material and impact conditions, and constants of the equation needs to be determined for a given problem. The authors have investigated the hole size formation for steel sphere impacting thin steel target with velocity ranging from 2 km/s to 4 km/s and obliquity between 0 degrees and 70 degrees. The constants for a prototype non-dimensional empirical equation for hole size have been determined using hydro-code simulation and a few experiments have been conducted to validate the predictions. (C) 2017 The Authors. Published by Elsevier Ltd.

关键词： Hypervelocity impact bumper plate empirical equation hole size multi variable regression

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Investigation of Hole Size Formation by Steel Sphere Impacting on Thin Plate at Hypervelocity

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Procedia Engineering 2017年 173卷 323-330页

作者： K.D. Dhote P.N. Verma Armament Research and Development Establishment Dr. Homi Bhabha Road Pashan Pune - 411021 India

Protective structures against hypervelocity impact of fragments consists of a thin skin (bumper plate) followed by air gap and main structure. The bumper causes shattering of the fragment and reduces fragment penetration capability to the main structure. Hole size formed in the bumper plate is indicative of damage extent to the main structure and is a direct measure of exposure to new impacts. An extensive study for characterization of hole size in thin aluminium plates due to hypervelocity impacts of aluminium projectiles has been reported in literature. An empirical equation is generally used to estimate the hole size which depends on non-dimensional parameters relating the target and projectile geometry, material and impact conditions, and constants of the equation needs to be determined for a given problem. The authors have investigated the hole size formation for steel sphere impacting thin steel target with velocity ranging from 2 km/s to 4 km/s and obliquity between 0° and 70°. The constants for a prototype non-dimensional empirical equation for hole size have been determined using hydro-code simulation and a few experiments have been conducted to validate the predictions.

关键词： Hypervelocity impact bumper plate empirical equation hole size multi variable regression

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A novel risk score that incorporates recipient and donor variables to predict 1-year mortality in the current era of lung transplantation

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JOURNAL OF HEART AND LUNG TRANSPLANTATION 2015年第11期34卷 1449-1454页

作者： Grimm, Joshua C. Valero, Vicente, III Magruder, J. Trent Kilic, Arman Dungan, Samuel P. Silhan, Leann L. Shah, Pali D. Kim, Bo S. Merlo, Christian A. Sciortino, Christopher M. Shah, Ashish S. Johns Hopkins Univ Hosp Div Cardiac Surg Baltimore MD 21287 USA Johns Hopkins Univ Hosp Div Pulm & Crit Care Baltimore MD 21287 USA

BACKGROUND: In this study we sought to construct a novel scoring system to pre-operatively stratify a patient's risk of 1-year mortality after lung transplantation (LTx) based on recipient- and donor-specific characteristics. METHODS: The UNOS database was queried for adult (>= 18 years) patients undergoing LTx between May 1, 2005 and December 31, 2012. The population was randomly divided in a 4:1 fashion into derivation and validation cohorts. A multivariable logistic regression model for 1-year mortality was constructed within the derivation cohort. Points were then assigned to independent predictors (p < 0.05) based on relative odds ratios. Risk groups were established based on score ranges. RESULTS: During the study period, 9,185 patients underwent LTx and the 1-year mortality was 18.0% (n = 1,654). There was a similar distribution of variables between the derivation (n = 7,336) and validation (n = 1,849) cohorts. Of the 14 covariates included in the final model, 9 were ultimately allotted point values (maximum score = 70). The model exhibited good predictive strength (c = 0.65) in the derivation cohort and demonstrated a strong correlation between the observed and expected rates of 1-year mortality in the validation cohort (r = 0.87). The low-risk (score 0 to 11), intermediate-risk (score 12 to 21) and high-risk (score >= 22) groups had a 10.8%, 17.1% and 32.0% risk of mortality (p < 0.001), respectively. CONCLUSIONS: This is the first scoring system that incorporates both recipient- and donor-related factors to predict 1-year mortality after LTx. Its use could assist providers in the identification of patients at highest risk for poor post-transplant outcomes. (C) 2015 International Society for Heart and Lung Transplantation. All rights reserved.

关键词： lung transplantation mortality risk stratification multi variable regression

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