Machinability of Carbon Fiber Reinforced Polymer (CFRP) Composites: Modeling and Optimization Using Taguchi Analysis and Multi-Objective Genetic Algorithm

Carbon Fiber Reinforced Polymer (CFRP) composites have been widely used in aerospace, automotive, nuclear, and biomedical industries due to their high strength to weight ratio, corrosion resistant durability and excellent thermo-mechanical properties in non-oxidative atmospheres. Machining of CFRP composites has always been a challenge for the manufacturers. In this study, turning operation has been performed on CFRP composites to investigate the effects of cutting parameters namely cutting speed, feed rate and depth of cut on the output characteristics including cutting force, surface roughness and tool wear using Taguchi Analysis. Regression Analysis has been used to develop mathematical model for cutting force, surface roughness and tool wear as a function of cutting speed, feed rate and depth of cut. A comparative study has been performed between coated and uncoated carbide inserts based on the optimal parameters in multi-objective optimization of cutting force, tool wear and surface roughness using Multi-Objective Genetic Algorithm (MOGA) during turning of CFRP composites in a CNC lathe machine. It was found that coated carbides provide lower tool wear and surface roughness, but higher cutting force compared to those of uncoated carbides during turning of CFRP composites. Feed rate has been found as the most significant parameters in turning of CFRP composites to minimize cutting force, tool wear and surface roughness. Cutting speed has been found very significant in tool wear when using uncoated carbide inserts

Turning of Carbon Fiber Reinforced Polymer (CFRP) Composites: Process Modeling and Optimization using Taguchi Analysis and Multi-Objective Genetic Algorithm

Carbon Fiber Reinforced Polymer (CFRP) composites have been widely used in aerospace, automotive, nuclear, and biomedical industries due to their high strength-to-weight ratio, corrosion resistance, durability, and excellent thermo-mechanical properties in non-oxidative atmospheres. Machining of CFRP composites has always been a challenge for manufacturers. In this research, a comparative study was performed between the optimal machining parameters of coated and uncoated carbide inserts obtained from the Multi-Objective Genetic Algorithm during turning of CFRP composites. It was found that coated carbide inserts provide lower tool wear and surface roughness, but higher cutting forces compared to those of uncoated carbide inserts during turning of CFRP composites. Taguchi Analysis was performed to investigate the effects of machining parameters (cutting speed, feed rate and depth of cut) on the output characteristics including cutting force, surface roughness and tool wear. The feed rate was found as the most significant machining parameter in turning of CFRP composites to minimize cutting force and surface roughness using both coated and uncoated carbide inserts. However, feed rate and cutting speed has been found as the most significant machining parameters for coated and uncoated carbide inserts respectively to minimize the tool wear. Regression Analysis has been performed to develop mathematical models for cutting force, surface roughness and tool wear as a function of cutting speed, feed rate and depth of cut. Higher R2 values and well fitted regression lines of normal probability plots in regression analysis indicate that the coefficients of mathematical models are statistically significant. The significance of this study is to emphasize the differences of performances between coated and uncoated carbide inserts during turning of CFRP composites in terms of cutting force, tool wear and surface roughness with the combination of different machining parameters (cutting speed, feed rate and tool wear) using data analysis tools such as Taguchi Analysis, Regression Analysis and Multi-Objective Optimization

Modeling and optimization of process parameters in face milling of Ti6Al4V alloy using Taguchi and grey relational analysis

Titanium alloys are extensively used in aerospace, missiles, rockets, naval ships, automotive, medical devices, and even the consumer electronics industry where a high strength to density ratio, lightweight, high corrosion resistance, and resistance to high temperatures are important. The machining of these alloys has always been challenging for manufacturers. This article investigates the combined effect of radial depth, cutting speed and feed rate on cutting forces, tool life, and surface roughness during face milling of Ti6Al4V alloy. This study focuses on the significance of radial depth of cut on cutting force, tool life and surface roughness compared to that of cutting speed and feed rate during face milling of Ti6Al4V alloy. In this paper, mono and multi-objective optimization of the response characteristics have been conducted to find out the optimal input parameters, namely, cutting speed, feed rate, and radial depth of cut. Taguchi method and analysis of variance (ANOVA) analysis have been used for mono-objective optimization, while Taguchi-based grey relational analysis has been used for multi-objective optimization. The regression analysis has been performed for developing mathematical models to predict the surface roughness, tool life, and cutting forces. According to ANOVA analysis, the most significant parameters for tool life and cutting force (FY) are cutting speed, and radial depth of cut, respectively, while feed rate is observed to be the most significant parameter for surface roughness and force (FX). The optimal combination of input parameters for tool life and FY are 50m/min cutting speed, 0.02mm/rev feed rate, and 7.5mm radial depth of cut. However, the optimal parameters for surface roughness are 65m/min cutting speed, 0.02mm/rev feed rate, and 7.5mm radial depth of cut. For FX, the optimal condition is observed as cutting speed 57.5m/min, 0.02mm/rev feed rate, and 7.5mm radial depth of cut. A validation experiment, conducted at the optimal parameters of surface roughness, shows an improvement of 31.29% compared to the surface roughness at initial condition. Taguchi-based grey relational analysis for multi-objective optimization shows an improvement of 55.81%, 6.12%, and 23.98% in tool life, surface roughness, and FY, respectively. ANOVA analysis based on grey relational grade shows that the radial depth of cut is the most significant parameter for multi-objective optimization during the face milling of Ti6Al4V

Prospects of Hyperloop Transportation Technology: A Case of China

Hyperloop transportation technology is amongst the most promising sustainable and climate-friendly transportation systems of the modern era. Now China has taken steps to build this transportation system in Tongren city, which located on Guizhou's eastern part [8]. So far, not much work has been conducted on the prospects of this technology, especially for China. In this paper based on extensive literature review, we have analyzed the prospects of this technology in China. Furthermore, this article also discusses the possible hurdles and proposes some suggestions for overcoming the problems in the adoption of this climate-friendly technology

The impact of surgical delay on resectability of colorectal cancer: An international prospective cohort study

AIM: The SARS-CoV-2 pandemic has provided a unique opportunity to explore the impact of surgical delays on cancer resectability. This study aimed to compare resectability for colorectal cancer patients undergoing delayed versus non-delayed surgery. METHODS: This was an international prospective cohort study of consecutive colorectal cancer patients with a decision for curative surgery (January-April 2020). Surgical delay was defined as an operation taking place more than 4 weeks after treatment decision, in a patient who did not receive neoadjuvant therapy. A subgroup analysis explored the effects of delay in elective patients only. The impact of longer delays was explored in a sensitivity analysis. The primary outcome was complete resection, defined as curative resection with an R0 margin. RESULTS: Overall, 5453 patients from 304 hospitals in 47 countries were included, of whom 6.6% (358/5453) did not receive their planned operation. Of the 4304 operated patients without neoadjuvant therapy, 40.5% (1744/4304) were delayed beyond 4 weeks. Delayed patients were more likely to be older, men, more comorbid, have higher body mass index and have rectal cancer and early stage disease. Delayed patients had higher unadjusted rates of complete resection (93.7% vs. 91.9%, P = 0.032) and lower rates of emergency surgery (4.5% vs. 22.5%, P < 0.001). After adjustment, delay was not associated with a lower rate of complete resection (OR 1.18, 95% CI 0.90-1.55, P = 0.224), which was consistent in elective patients only (OR 0.94, 95% CI 0.69-1.27, P = 0.672). Longer delays were not associated with poorer outcomes. CONCLUSION: One in 15 colorectal cancer patients did not receive their planned operation during the first wave of COVID-19. Surgical delay did not appear to compromise resectability, raising the hypothesis that any reduction in long-term survival attributable to delays is likely to be due to micro-metastatic disease

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Delaying surgery for patients with a previous SARS-CoV-2 infection

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