Pub Date : 2024-01-31DOI: 10.24840/2183-6493_0010-001_002057
Francisca Nunes, Mariana Trindade, Jose M. Costa
The fast development of Additive Manufacturing (AM) technology over the past few decades has been remarkable, and it is expected that this development will continue. This technology has benefits over conventional production techniques, such as its flexibility, dependability, energy usage, and material efficiency. The subject of this article is the design and optimization of support for smart glasses based on a Vuzix model using nTopology and Fusion 360. The whole process of creating the support evolves from selecting the appropriate material (Onyx) and AM process to this type of component (Fused Filament Fabrication), to adjusting the CAD model of the glasses, using Fusion360 to create the initial design of the support, and nTopology to optimize the model. A static analysis simulation was also performed to validate the different models made.
{"title":"Production and nTopology optimization of an additive manufactured support for smart glasses","authors":"Francisca Nunes, Mariana Trindade, Jose M. Costa","doi":"10.24840/2183-6493_0010-001_002057","DOIUrl":"https://doi.org/10.24840/2183-6493_0010-001_002057","url":null,"abstract":"The fast development of Additive Manufacturing (AM) technology over the past few decades has been remarkable, and it is expected that this development will continue. This technology has benefits over conventional production techniques, such as its flexibility, dependability, energy usage, and material efficiency. The subject of this article is the design and optimization of support for smart glasses based on a Vuzix model using nTopology and Fusion 360. The whole process of creating the support evolves from selecting the appropriate material (Onyx) and AM process to this type of component (Fused Filament Fabrication), to adjusting the CAD model of the glasses, using Fusion360 to create the initial design of the support, and nTopology to optimize the model. A static analysis simulation was also performed to validate the different models made.","PeriodicalId":36339,"journal":{"name":"U.Porto Journal of Engineering","volume":"2 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140474214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-30DOI: 10.24840/2183-6493_010-001_001279
R. Lopes, Rui L. Amaral, Sara S. Miranda, Abel D. Santos, Pedro M. G. P. Moreira
Sheet metal forming is used to process a substantial percentage of automobile components, and the so-called springback behavior is of primary importance, in order to obtain the final part with an accurate geometry. This paper describes a springback research that employs three different materials often used in the automobile industry: DP780, HSLA420, and AA5754. The unconstrained cylindrical bending test (UCB test) will be utilized to assess the springback prediction for selected materials. In this study, experimental data is collected and numerical results are provided utilizing finite element techniques. Results show that UCB test is an adequate benchmark for analysis of springback behavior of sheet metallic materials and it has also been observed a close agreement between numerical results and experiments.
{"title":"Numerical analysis of springback with experimental validation using UCB test","authors":"R. Lopes, Rui L. Amaral, Sara S. Miranda, Abel D. Santos, Pedro M. G. P. Moreira","doi":"10.24840/2183-6493_010-001_001279","DOIUrl":"https://doi.org/10.24840/2183-6493_010-001_001279","url":null,"abstract":"Sheet metal forming is used to process a substantial percentage of automobile components, and the so-called springback behavior is of primary importance, in order to obtain the final part with an accurate geometry. This paper describes a springback research that employs three different materials often used in the automobile industry: DP780, HSLA420, and AA5754. The unconstrained cylindrical bending test (UCB test) will be utilized to assess the springback prediction for selected materials. In this study, experimental data is collected and numerical results are provided utilizing finite element techniques. Results show that UCB test is an adequate benchmark for analysis of springback behavior of sheet metallic materials and it has also been observed a close agreement between numerical results and experiments.","PeriodicalId":36339,"journal":{"name":"U.Porto Journal of Engineering","volume":"88 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140481926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-30DOI: 10.24840/2183-6493_010-001_002051
Beatriz Monteiro, Francisca Rocha, Jose M. Costa
The robot gripper works analogously to the human hand, being the end effector of a robotic mechanism and acting as a bridge between the robot and the environment. A topology optimized gripper can be fully functional while allowing weight reduction. In this paper, the topology optimization of a 316L-SS four-clamp gripper capable of withstanding a 2 N load was conducted using the nTopology software. Fusion360 static stress analysis showed a reduction of 43% in weight, keeping the safety factor above 3, and leading to a displacement of 0,0067 mm. Finally, the maximum induced stress was shown not to cause permanent deformation of the clamp since it was observed to be inferior to the yield strength of 316L-SS.
{"title":"Topology Optimization of a Robot Gripper with nTopology","authors":"Beatriz Monteiro, Francisca Rocha, Jose M. Costa","doi":"10.24840/2183-6493_010-001_002051","DOIUrl":"https://doi.org/10.24840/2183-6493_010-001_002051","url":null,"abstract":"The robot gripper works analogously to the human hand, being the end effector of a robotic mechanism and acting as a bridge between the robot and the environment. A topology optimized gripper can be fully functional while allowing weight reduction. In this paper, the topology optimization of a 316L-SS four-clamp gripper capable of withstanding a 2 N load was conducted using the nTopology software. Fusion360 static stress analysis showed a reduction of 43% in weight, keeping the safety factor above 3, and leading to a displacement of 0,0067 mm. Finally, the maximum induced stress was shown not to cause permanent deformation of the clamp since it was observed to be inferior to the yield strength of 316L-SS.","PeriodicalId":36339,"journal":{"name":"U.Porto Journal of Engineering","volume":"656 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140482990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-24DOI: 10.24840/2183-6493_009-005_002195
Sebastião Ventura, Lino Maia
The alkali-activated materials are being understood as the best chance to replace the Portland cement to become the concrete industry greener in terms of CO2 emissions. However, these alternatives binders face challenges, among others related to durability. The present work regards to a short literature review about the durability in concrete produced with binders that are alkali-activated materials. The mechanisms of degradation are discussed, namely due to acid attack, capillarity, carbonation, permeability , porosity and steel corrosion. Comparison to the concrete that used Portland cement as binder is frequently used.
{"title":"Durability of concrete with alkali-activated materials: a short literature review","authors":"Sebastião Ventura, Lino Maia","doi":"10.24840/2183-6493_009-005_002195","DOIUrl":"https://doi.org/10.24840/2183-6493_009-005_002195","url":null,"abstract":"The alkali-activated materials are being understood as the best chance to replace the Portland cement to become the concrete industry greener in terms of CO2 emissions. However, these alternatives binders face challenges, among others related to durability. The present work regards to a short literature review about the durability in concrete produced with binders that are alkali-activated materials. The mechanisms of degradation are discussed, namely due to acid attack, capillarity, carbonation, permeability , porosity and steel corrosion. Comparison to the concrete that used Portland cement as binder is frequently used.","PeriodicalId":36339,"journal":{"name":"U.Porto Journal of Engineering","volume":"2018 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139239492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-24DOI: 10.24840/2183-6493_009-005_002176
Bruno D. A. Pinheiro, A. R. Almeida, M. Monte
The present work reports an experimental study aiming to determine several thermodynamic properties of fusion and sublimation of the chromophore N,N-dimethyl-4-nitroaniline. This compound is commonly used as a reference in studies focused on the non-linear optical (NLO) characteristics of chromophores. Using the Knudsen mass-loss effusion method, the vapor pressures of the crystalline phase of N,N-dimethyl-4-nitroaniline were measured over the temperature range between 341.1 K and 363.5 K. The standard molar enthalpy, entropy, and Gibbs energy of sublimation were calculated from the experimental results, at 298.15 K, and compared with those given in the literature. Differential scanning calorimetry was used to determine the temperature and enthalpy of fusion, as well as the isobaric heat capacities of the crystalline compound under study. Additionally, the enthalpic and entropic contributions to N,N-dimethyl-4-nitroaniline’s volatility were assessed, and it was determined that is greatly conditioned by enthalpic factors.
本研究报告介绍了一项实验研究，旨在确定发色团 N,N-二甲基-4-硝基苯胺融合和升华的若干热力学性质。这种化合物通常被用作研究发色团非线性光学（NLO）特性的参照物。利用克努森质量损失流出法，在 341.1 K 至 363.5 K 的温度范围内测量了 N,N-二甲基-4-硝基苯胺结晶相的蒸气压。根据实验结果计算了 298.15 K 时的标准摩尔焓、熵和升华吉布斯能，并与文献中给出的结果进行了比较。差示扫描量热法用于测定所研究的晶体化合物的温度、熔焓和等压热容。此外，还评估了 N,N-二甲基-4-硝基苯胺挥发性的焓贡献和熵贡献，并确定焓因素在很大程度上决定了其挥发性。
{"title":"Phase transitions properties of N,N-dimethyl-4-nitroaniline","authors":"Bruno D. A. Pinheiro, A. R. Almeida, M. Monte","doi":"10.24840/2183-6493_009-005_002176","DOIUrl":"https://doi.org/10.24840/2183-6493_009-005_002176","url":null,"abstract":"The present work reports an experimental study aiming to determine several thermodynamic properties of fusion and sublimation of the chromophore N,N-dimethyl-4-nitroaniline. This compound is commonly used as a reference in studies focused on the non-linear optical (NLO) characteristics of chromophores. Using the Knudsen mass-loss effusion method, the vapor pressures of the crystalline phase of N,N-dimethyl-4-nitroaniline were measured over the temperature range between 341.1 K and 363.5 K. The standard molar enthalpy, entropy, and Gibbs energy of sublimation were calculated from the experimental results, at 298.15 K, and compared with those given in the literature. Differential scanning calorimetry was used to determine the temperature and enthalpy of fusion, as well as the isobaric heat capacities of the crystalline compound under study. Additionally, the enthalpic and entropic contributions to N,N-dimethyl-4-nitroaniline’s volatility were assessed, and it was determined that is greatly conditioned by enthalpic factors.","PeriodicalId":36339,"journal":{"name":"U.Porto Journal of Engineering","volume":"77 3-4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139238905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-24DOI: 10.24840/2183-6493_009-005_001937
Pedro Félix
The growing number of battery electric vehicles (BEV) and plug-in hybrid electric vehicles (PHEV) brings the need of more fast charging stations across cities and highway stops. This charging stations toned to be connected to the electrical grid via existent facilities, causing constraints such as power availability. This study brings an approach for the planning and operation of such energy hubs by coping with this challenge by deploying a Battery-based Energy Storage System (BESS). With the BESS integration, it is expected to minimize utilization and overall energy costs, preventing infrastructure upgrades, and enhancing the integration of renewable energy resources. This approach sizes a stationary energy storage system with lithium-ion technology batteries through a co-optimization of the planning and operation stages, integrated in an electrical installation that will implement fast charging stations. This sizing is a result of an optimization based on the interior point algorithm, where the objective is to minimize the costs of maintenance, operation, and installation of a BESS, while properly modelling the different resources such as the BESS, the charging station and EV charging and PV generation.
{"title":"Battery Energy Storage System Optimal Sizing in a Battery Electric Vehicle Fast Charging Infrastructure","authors":"Pedro Félix","doi":"10.24840/2183-6493_009-005_001937","DOIUrl":"https://doi.org/10.24840/2183-6493_009-005_001937","url":null,"abstract":"The growing number of battery electric vehicles (BEV) and plug-in hybrid electric vehicles (PHEV) brings the need of more fast charging stations across cities and highway stops. This charging stations toned to be connected to the electrical grid via existent facilities, causing constraints such as power availability. This study brings an approach for the planning and operation of such energy hubs by coping with this challenge by deploying a Battery-based Energy Storage System (BESS). With the BESS integration, it is expected to minimize utilization and overall energy costs, preventing infrastructure upgrades, and enhancing the integration of renewable energy resources. This approach sizes a stationary energy storage system with lithium-ion technology batteries through a co-optimization of the planning and operation stages, integrated in an electrical installation that will implement fast charging stations. This sizing is a result of an optimization based on the interior point algorithm, where the objective is to minimize the costs of maintenance, operation, and installation of a BESS, while properly modelling the different resources such as the BESS, the charging station and EV charging and PV generation.","PeriodicalId":36339,"journal":{"name":"U.Porto Journal of Engineering","volume":"83 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139241832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-24DOI: 10.24840/2183-6493_009-005_002156
João Carlos Bittencourt, Walber Conceição de Jesus Rocha
Embedded applications are increasingly prevalent in various domains, from consumer electronics to industrial automation and smart cities. With the advances in integrated circuit manufacturing technologies, low-power chips can now execute complex algorithms, including machine learning models. However, the computational constraints of embedded devices require compact and efficient neural network models, as well as software frameworks and optimisation techniques tailored to their hardware resources. This study investigates the implementation of Convolutional Neural Network (CNN) models for gesture recognition on an STM32F4 microcontroller, by exploring the impact of freezing layers, fine-tuning and pruning techniques on pre-trained CNN models. The results demonstrate that fine-tuning and freezing layers improve accuracy by up to 18%. Additionally, freezing layers by 10% and 20% improved the accuracy. Finally, we demonstrate that pruning reduced the model size by 90%, enabling it to perform gesture recognition on small devices. These findings are significant for developing software and optimisation techniques for embedded systems, particularly in the context of the Internet of Things.
{"title":"Optimisation Techniques for Compact CNN on Embedded Systems for Gesture Recognition","authors":"João Carlos Bittencourt, Walber Conceição de Jesus Rocha","doi":"10.24840/2183-6493_009-005_002156","DOIUrl":"https://doi.org/10.24840/2183-6493_009-005_002156","url":null,"abstract":"Embedded applications are increasingly prevalent in various domains, from consumer electronics to industrial automation and smart cities. With the advances in integrated circuit manufacturing technologies, low-power chips can now execute complex algorithms, including machine learning models. However, the computational constraints of embedded devices require compact and efficient neural network models, as well as software frameworks and optimisation techniques tailored to their hardware resources. This study investigates the implementation of Convolutional Neural Network (CNN) models for gesture recognition on an STM32F4 microcontroller, by exploring the impact of freezing layers, fine-tuning and pruning techniques on pre-trained CNN models. The results demonstrate that fine-tuning and freezing layers improve accuracy by up to 18%. Additionally, freezing layers by 10% and 20% improved the accuracy. Finally, we demonstrate that pruning reduced the model size by 90%, enabling it to perform gesture recognition on small devices. These findings are significant for developing software and optimisation techniques for embedded systems, particularly in the context of the Internet of Things.","PeriodicalId":36339,"journal":{"name":"U.Porto Journal of Engineering","volume":"2002 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139239195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-24DOI: 10.24840/2183-6493_009-005_001965
Manuel Pambasange Jorge
The goal of this study was to develop a mobile app that would be used as a self-help and stress-reduction tool for university students. The StressonCampus app adopted a hybrid questionnaire based on the DASS-21 and Kessler PT models, which identifies the level of stress and, likewise, provides suggestions for relaxation exercises. The improved version of the app includes a chatbot or conversation agent that allows a dialogue with the student to detect the student's stress situation and present a relaxation recommendation based on it.
{"title":"StressOnCampus: An App for Stress Management","authors":"Manuel Pambasange Jorge","doi":"10.24840/2183-6493_009-005_001965","DOIUrl":"https://doi.org/10.24840/2183-6493_009-005_001965","url":null,"abstract":"The goal of this study was to develop a mobile app that would be used as a self-help and stress-reduction tool for university students. The StressonCampus app adopted a hybrid questionnaire based on the DASS-21 and Kessler PT models, which identifies the level of stress and, likewise, provides suggestions for relaxation exercises. The improved version of the app includes a chatbot or conversation agent that allows a dialogue with the student to detect the student's stress situation and present a relaxation recommendation based on it.","PeriodicalId":36339,"journal":{"name":"U.Porto Journal of Engineering","volume":"2018 29","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139239638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-24DOI: 10.24840/2183-6493_009-005_001531
Malek Miled, M. B. Ben Messaoud
Single-channel speech enhancement refers to the task of improving the quality and intelligibility of a speech signal in a noisy environment. Time-domain and time-frequency-domain methods are two main categories of approaches for speech enhancement. In this paper, we propose a approach based on a cross-domain framework. This framework utilizes our knowledge of the spectrogram and overcomes some of the limitations faced by time-frequency domain methods. First, we apply the intrinsic mode functions of the empirical mode decomposition and an improved version of principal component analysis. Then, we design a cross-domain learning framework to determine the correlations along the frequency and time axes. At low SNR = -5 dB, the effectiveness of our proposed approach is demonstrated by its performance based on objective and subjective measures. With average scores of -0.49, 2.47, 2.44, and 0.68 for SegSNR, PESQ, Cov, and STOI, respectively. The results highlight the success of our approach in addressing low SNR conditions.
单通道语音增强是指在噪声环境中提高语音信号的质量和可懂度。时域和时频域方法是语音增强的两大类方法。在本文中，我们提出了一种基于跨域框架的方法。该框架利用了我们对频谱图的了解，克服了时频域方法所面临的一些限制。首先，我们应用了经验模式分解的固有模式函数和改进版的主成分分析。然后，我们设计了一个跨域学习框架，以确定沿频率轴和时间轴的相关性。在 SNR = -5 dB 的低信噪比条件下，我们提出的方法的有效性通过其基于客观和主观测量的性能得到了证明。SegSNR、PESQ、Cov 和 STOI 的平均得分分别为 -0.49、2.47、2.44 和 0.68。这些结果凸显了我们的方法在解决低信噪比条件下的成功。
{"title":"An improved deep learning approach for speech enhancement","authors":"Malek Miled, M. B. Ben Messaoud","doi":"10.24840/2183-6493_009-005_001531","DOIUrl":"https://doi.org/10.24840/2183-6493_009-005_001531","url":null,"abstract":"Single-channel speech enhancement refers to the task of improving the quality and intelligibility of a speech signal in a noisy environment. Time-domain and time-frequency-domain methods are two main categories of approaches for speech enhancement. In this paper, we propose a approach based on a cross-domain framework. This framework utilizes our knowledge of the spectrogram and overcomes some of the limitations faced by time-frequency domain methods. First, we apply the intrinsic mode functions of the empirical mode decomposition and an improved version of principal component analysis. Then, we design a cross-domain learning framework to determine the correlations along the frequency and time axes. At low SNR = -5 dB, the effectiveness of our proposed approach is demonstrated by its performance based on objective and subjective measures. With average scores of -0.49, 2.47, 2.44, and 0.68 for SegSNR, PESQ, Cov, and STOI, respectively. The results highlight the success of our approach in addressing low SNR conditions.","PeriodicalId":36339,"journal":{"name":"U.Porto Journal of Engineering","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139241401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-24DOI: 10.24840/2183-6493_009-005_002152
Rúben Costa
The drilling process of composite materials, such as the carbon fiber reinforced polymer (CFRP), constitutes a challenging task due to their inhomogeneous and anisotropic characteristics, besides the highly abrasive wear behaviour of their fibers. Accordingly, machining parameters should be carefully studied to optimize the process, leading to a better surface quality (avoiding defects in the CFRP) and to a lower wear behaviour of the cutting tool. This study proposed to test the drilling of a CFRP with a thermoplastic matrix using two different tool geometries (conventional and double-point angle drill) and varying two parameters, feed (f) and spindle speed (n), each one with two levels. It was concluded that the double-point angle drill with lower spindle speeds generates lower thrust force and torque values, as well as better hole quality. Higher spindle speeds combined with lower feeds result in fractured chips, in contrast with continuous chips for the other combinations.
{"title":"Impact of different parameters in the drilling of CFRPs with nanocrystalline diamond coated tools","authors":"Rúben Costa","doi":"10.24840/2183-6493_009-005_002152","DOIUrl":"https://doi.org/10.24840/2183-6493_009-005_002152","url":null,"abstract":"The drilling process of composite materials, such as the carbon fiber reinforced polymer (CFRP), constitutes a challenging task due to their inhomogeneous and anisotropic characteristics, besides the highly abrasive wear behaviour of their fibers. Accordingly, machining parameters should be carefully studied to optimize the process, leading to a better surface quality (avoiding defects in the CFRP) and to a lower wear behaviour of the cutting tool. This study proposed to test the drilling of a CFRP with a thermoplastic matrix using two different tool geometries (conventional and double-point angle drill) and varying two parameters, feed (f) and spindle speed (n), each one with two levels. It was concluded that the double-point angle drill with lower spindle speeds generates lower thrust force and torque values, as well as better hole quality. Higher spindle speeds combined with lower feeds result in fractured chips, in contrast with continuous chips for the other combinations.","PeriodicalId":36339,"journal":{"name":"U.Porto Journal of Engineering","volume":"2014 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139239205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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