In the fused filament fabrication (FFF) based additive manufacturing process, finding optimum printing parameters for achieving the required mechanical properties of the FFF-built part is challenging. In this study, a representative volume element (RVE) based mesoscale approach was developed to describe the influences of printing parameters on the mechanical behaviors of the 3D printed parts. It was shown that the stress-strain curves up to failure obtained from RVE simulations were well verified by experimental tensile test data of printed PLA samples. Then, effective tensile properties of samples manufactured using different raster angles (0°, 45°/−45°, and 90°) and a wide range of layer heights and widths were predicted and correlated with their respective local damage occurrences. The raster angle strongly affected the elastic modulus and tensile strength. The orientation between interlayer voids and loading direction governed local stress distribution, interface failure, and total deformation of FFF samples. An increased layer height and decreased layer width resulted in a more significant fraction of voids between layers and thus lowered stiffness and tensile strength. The introduced RVE model can serve as a simple tool for determining homogenized responses and studying local stress-strain developments and failure of complex printed parts according to the used printing parameters.
{"title":"Effect of raster and layer characteristics on tensile behavior and failure of FFF printed PLA samples by representative volume element model","authors":"Pakkhanan Chansamai, Tirada Seangpong, Vitoon Uthaisangsuk","doi":"10.1177/09544054231202210","DOIUrl":"https://doi.org/10.1177/09544054231202210","url":null,"abstract":"In the fused filament fabrication (FFF) based additive manufacturing process, finding optimum printing parameters for achieving the required mechanical properties of the FFF-built part is challenging. In this study, a representative volume element (RVE) based mesoscale approach was developed to describe the influences of printing parameters on the mechanical behaviors of the 3D printed parts. It was shown that the stress-strain curves up to failure obtained from RVE simulations were well verified by experimental tensile test data of printed PLA samples. Then, effective tensile properties of samples manufactured using different raster angles (0°, 45°/−45°, and 90°) and a wide range of layer heights and widths were predicted and correlated with their respective local damage occurrences. The raster angle strongly affected the elastic modulus and tensile strength. The orientation between interlayer voids and loading direction governed local stress distribution, interface failure, and total deformation of FFF samples. An increased layer height and decreased layer width resulted in a more significant fraction of voids between layers and thus lowered stiffness and tensile strength. The introduced RVE model can serve as a simple tool for determining homogenized responses and studying local stress-strain developments and failure of complex printed parts according to the used printing parameters.","PeriodicalId":20663,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture","volume":"114 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135816124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-20DOI: 10.1177/09544054231197337
Jiakang Zhou, Mingming Lu, Jieqiong Lin, Xiaoxiao Su, Wenqing Wei
To predict the cutting force in machining of SiCp/Al composites by ultrasonic elliptical vibration-assisted turning (UEVT) technology, a semi-empirical geometric model considering the deformation and friction characteristics in different deformation areas is established in this paper. During UEVT, the resistance force acting on cutting edge is divided into three parts according to different deformation zones: shear force, interface friction, and plowing force. The vibration characteristic functions are also coupled to the semi-empirical geometric model of cutting force. A three factor and four level orthogonal tests is implemented to verify the validity of geometric model, and the single factor cutting experiments are also conducted to evaluate the influence law of relevant parameter on cutting force. Experimental results show that the deviation between the calculated value of cutting force and measured average value is less than 17%, and the average deviation is 8.16%, which proved that the semi-empirical geometric model can effectively predict the cutting force of SiCp/Al composites during UEVT. In addition, the influence of cutting parameters and volume fraction on cutting force is discussed, which provides a theoretical guidance for the outstanding machinability of SiCp/Al composites in UEVT.
{"title":"Analytical modeling of cutting force in machining of SiCp/Al composites by ultrasonic elliptical vibration-assisted turning","authors":"Jiakang Zhou, Mingming Lu, Jieqiong Lin, Xiaoxiao Su, Wenqing Wei","doi":"10.1177/09544054231197337","DOIUrl":"https://doi.org/10.1177/09544054231197337","url":null,"abstract":"To predict the cutting force in machining of SiCp/Al composites by ultrasonic elliptical vibration-assisted turning (UEVT) technology, a semi-empirical geometric model considering the deformation and friction characteristics in different deformation areas is established in this paper. During UEVT, the resistance force acting on cutting edge is divided into three parts according to different deformation zones: shear force, interface friction, and plowing force. The vibration characteristic functions are also coupled to the semi-empirical geometric model of cutting force. A three factor and four level orthogonal tests is implemented to verify the validity of geometric model, and the single factor cutting experiments are also conducted to evaluate the influence law of relevant parameter on cutting force. Experimental results show that the deviation between the calculated value of cutting force and measured average value is less than 17%, and the average deviation is 8.16%, which proved that the semi-empirical geometric model can effectively predict the cutting force of SiCp/Al composites during UEVT. In addition, the influence of cutting parameters and volume fraction on cutting force is discussed, which provides a theoretical guidance for the outstanding machinability of SiCp/Al composites in UEVT.","PeriodicalId":20663,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136308084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-19DOI: 10.1177/09544054231199520
Ahmed Hamood, Artur J Jaworski, Liam Blunt, Andrew Townsend
Additive manufacturing is an option for the fabrication of heat exchangers for thermoacoustic applications. In thermoacoustic devices, heat exchangers are placed in oscillatory flow. A careful consideration of heat exchanger geometries examines the application of methodologies to optimise heat transfer and the temperature gradient. Additive manufacturing is proposed as an alternative fabrication technique that can overcome the current limitations of conventional fabrication machining. Six identical crossflow heat exchangers were made and tested, three from stainless steel and three from aluminium. The oscillatory flow moves back and forth through circular cross-section channels, and water flows in channels perpendicular to them. Heat transfer and temperature gradients were investigated at different drive ratios and mean pressures.
{"title":"The application of additive manufacturing to heat exchangers for oscillatory flow: A case study","authors":"Ahmed Hamood, Artur J Jaworski, Liam Blunt, Andrew Townsend","doi":"10.1177/09544054231199520","DOIUrl":"https://doi.org/10.1177/09544054231199520","url":null,"abstract":"Additive manufacturing is an option for the fabrication of heat exchangers for thermoacoustic applications. In thermoacoustic devices, heat exchangers are placed in oscillatory flow. A careful consideration of heat exchanger geometries examines the application of methodologies to optimise heat transfer and the temperature gradient. Additive manufacturing is proposed as an alternative fabrication technique that can overcome the current limitations of conventional fabrication machining. Six identical crossflow heat exchangers were made and tested, three from stainless steel and three from aluminium. The oscillatory flow moves back and forth through circular cross-section channels, and water flows in channels perpendicular to them. Heat transfer and temperature gradients were investigated at different drive ratios and mean pressures.","PeriodicalId":20663,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135016221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-08DOI: 10.1177/09544054231196270
Zhaopeng Hao, Xianglin Xu, Yihang Fan
In order to clarify the reasons for the emergence of problems such as high machining difficulty and poor machining surface quality encountered in the machining process of SiCp/Al composites, this paper presents a simulation study of the deformation mechanism occurring during the cutting process of SiCp/Al (SiC particle-reinforced Al matrix composites) by using the molecular dynamics (MD) method. The mechanism of strengthening and hardening occurring during cutting of SiCp/Al composites is discussed in terms of the slip expansion of dislocations and the interaction between different types of dislocations. It is found that the presence of SiC balls hinders the slip and expansion of dislocations in the Al (aluminum) matrix, resulting in the strengthening of the Al matrix between the SiC (silicon carbide) balls, mainly because the dislocations in the workpiece interact with each other during the cutting process to form dislocation tangles, stacking layer dislocations and dislocation locks, which hinder the slip and expansion of dislocations and thus increase the strength of the Al matrix. By analyzing the stress distribution inside the workpiece during the cutting process, it is found that the stress inside the workpiece is mainly concentrated in the area where the tool flank face is in contact with the workpiece, which is the main reason for the occurrence of working hardening in SiCp/Al composites.
{"title":"Deformation mechanisms in the cutting process of SiCp/Al composites using the molecular dynamics (MD) approach","authors":"Zhaopeng Hao, Xianglin Xu, Yihang Fan","doi":"10.1177/09544054231196270","DOIUrl":"https://doi.org/10.1177/09544054231196270","url":null,"abstract":"In order to clarify the reasons for the emergence of problems such as high machining difficulty and poor machining surface quality encountered in the machining process of SiCp/Al composites, this paper presents a simulation study of the deformation mechanism occurring during the cutting process of SiCp/Al (SiC particle-reinforced Al matrix composites) by using the molecular dynamics (MD) method. The mechanism of strengthening and hardening occurring during cutting of SiCp/Al composites is discussed in terms of the slip expansion of dislocations and the interaction between different types of dislocations. It is found that the presence of SiC balls hinders the slip and expansion of dislocations in the Al (aluminum) matrix, resulting in the strengthening of the Al matrix between the SiC (silicon carbide) balls, mainly because the dislocations in the workpiece interact with each other during the cutting process to form dislocation tangles, stacking layer dislocations and dislocation locks, which hinder the slip and expansion of dislocations and thus increase the strength of the Al matrix. By analyzing the stress distribution inside the workpiece during the cutting process, it is found that the stress inside the workpiece is mainly concentrated in the area where the tool flank face is in contact with the workpiece, which is the main reason for the occurrence of working hardening in SiCp/Al composites.","PeriodicalId":20663,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture","volume":"106 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86969408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The strict machining accuracy and surface finish requirements of manufactured products for aerospace parts make it particularly crucial to analyse the vibration performance of parallel robots as machining tools, which directly affects both of these factors. In this paper, a vibration modelling analysis for parallel robots with fewer-DOFs called defective parallel robots is presented, and the effects of four vibration models are also studied. The traditional spring-damping or elastic vibration models of two systems are presented, and the corresponding uncertain vibration systems are developed by considering the effects of gravity and the uncertain joint clearances. Taking a drilling defective parallel robot as an application example, four vibration models are derived, and the differences in natural frequency and vibration response are explored in numerical and experiment comparisons. The results shows that an uncertain system with six DOFs is closer to the experimental result (approximately 75.49%) than an elastic system (approximately 62.39%), which means that the accuracy has increased by 13.1%. The results of this paper reveal some of the reasons for the performance errors of the different vibration models for defective parallel robots, and the findings of this paper can provide a reference for the simplification and optimization of theoretical vibration models that ignore secondary factors.
{"title":"Vibration modelling analysis of defective parallel robots as machine tools for aerospace parts machining","authors":"Shuai Fan, Liping Zhang, Bo Hu, Guanyu Shen, Guangkui Song, Jing Qiu","doi":"10.1177/09544054231191632","DOIUrl":"https://doi.org/10.1177/09544054231191632","url":null,"abstract":"The strict machining accuracy and surface finish requirements of manufactured products for aerospace parts make it particularly crucial to analyse the vibration performance of parallel robots as machining tools, which directly affects both of these factors. In this paper, a vibration modelling analysis for parallel robots with fewer-DOFs called defective parallel robots is presented, and the effects of four vibration models are also studied. The traditional spring-damping or elastic vibration models of two systems are presented, and the corresponding uncertain vibration systems are developed by considering the effects of gravity and the uncertain joint clearances. Taking a drilling defective parallel robot as an application example, four vibration models are derived, and the differences in natural frequency and vibration response are explored in numerical and experiment comparisons. The results shows that an uncertain system with six DOFs is closer to the experimental result (approximately 75.49%) than an elastic system (approximately 62.39%), which means that the accuracy has increased by 13.1%. The results of this paper reveal some of the reasons for the performance errors of the different vibration models for defective parallel robots, and the findings of this paper can provide a reference for the simplification and optimization of theoretical vibration models that ignore secondary factors.","PeriodicalId":20663,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture","volume":"8 4 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79848664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-08DOI: 10.1177/09544054231196335
Song Yin, Haibo Zhou
Geometric rotary axis errors are one of the main factors affecting the dispensing positioning accuracy of five-axis vision dispensing machines. Hence, the accurate detection and compensation of these error terms is an important and challenging problem. In this study, a decoupling identification method for both position-dependent geometric errors and position-independent geometric errors of a rotary dispensing table is proposed based on vision measurement technology. According to this strategy, the screw theory and exponential product formula are used to establish a kinematic model of the end-effector, followed by the definition of the mapping relationship between position-independent geometric errors and axis posture. Then, to separate the coupling error terms of the rotating axes, a step-by-step identification strategy is proposed based on the least squares method. Furthermore, a coordinate search-based error compensation algorithm is developed, which avoids the inverse singular value problem and is insensitive to the error model. Finally, the effectiveness of the proposed identification algorithm and compensation algorithm is experimentally validated.
{"title":"Geometric error calibration and analysis of rotary axes on a five-axis dispensing machine","authors":"Song Yin, Haibo Zhou","doi":"10.1177/09544054231196335","DOIUrl":"https://doi.org/10.1177/09544054231196335","url":null,"abstract":"Geometric rotary axis errors are one of the main factors affecting the dispensing positioning accuracy of five-axis vision dispensing machines. Hence, the accurate detection and compensation of these error terms is an important and challenging problem. In this study, a decoupling identification method for both position-dependent geometric errors and position-independent geometric errors of a rotary dispensing table is proposed based on vision measurement technology. According to this strategy, the screw theory and exponential product formula are used to establish a kinematic model of the end-effector, followed by the definition of the mapping relationship between position-independent geometric errors and axis posture. Then, to separate the coupling error terms of the rotating axes, a step-by-step identification strategy is proposed based on the least squares method. Furthermore, a coordinate search-based error compensation algorithm is developed, which avoids the inverse singular value problem and is insensitive to the error model. Finally, the effectiveness of the proposed identification algorithm and compensation algorithm is experimentally validated.","PeriodicalId":20663,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture","volume":"12 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73584924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-08DOI: 10.1177/09544054231191650
Mehmet Aydın
Modeling of metal cutting using finite element (FE) method has been investigated in many studies. They make it possible to better understand the chip formation. However, the mesh dependence of the numerical solution is still unsolved. The purpose of this paper is the modeling and simulation of saw-toothed chip formation during high-speed orthogonal cutting. Further, the influences of mesh parameters on saw-toothed chip formation are investigated as an innovative highlight of this study. The investigation of high-speed cutting (HSC) is based on FE analysis, where the Johnson-Cook (JC) constitutive model is combined with an energy-based fracture criterion. The mesh parameters considered include element dimension, element orientation, and hourglass treatment. The results show that the peak and valley values of saw-toothed chip obtained through the model mesh10 × 10 are close to the measurements, but the pitch value is predicted with a larger error than those of peak and valley values. Square elements of dimension 10 μm can be also used to avoid the influence of element orientation on cutting forces with an error about 10%. When using square elements, the hourglass treatment causes slightly differences in chip morphology and cutting force. On the other hand, the enhanced is the more efficient method to prevent the hourglass effect for rectangular elements. The model mesh8 × 10 gives an error less than 15% for cutting force. Moreover, the effect of element dimension on cutting force can be reduced by applying the fracture energy criterion controlled through a characteristic length to different mesh dimensions.
{"title":"Finite element modeling of high-speed orthogonal cutting: A contribution to understanding the influence of mesh parameters on saw-toothed chip formation","authors":"Mehmet Aydın","doi":"10.1177/09544054231191650","DOIUrl":"https://doi.org/10.1177/09544054231191650","url":null,"abstract":"Modeling of metal cutting using finite element (FE) method has been investigated in many studies. They make it possible to better understand the chip formation. However, the mesh dependence of the numerical solution is still unsolved. The purpose of this paper is the modeling and simulation of saw-toothed chip formation during high-speed orthogonal cutting. Further, the influences of mesh parameters on saw-toothed chip formation are investigated as an innovative highlight of this study. The investigation of high-speed cutting (HSC) is based on FE analysis, where the Johnson-Cook (JC) constitutive model is combined with an energy-based fracture criterion. The mesh parameters considered include element dimension, element orientation, and hourglass treatment. The results show that the peak and valley values of saw-toothed chip obtained through the model mesh10 × 10 are close to the measurements, but the pitch value is predicted with a larger error than those of peak and valley values. Square elements of dimension 10 μm can be also used to avoid the influence of element orientation on cutting forces with an error about 10%. When using square elements, the hourglass treatment causes slightly differences in chip morphology and cutting force. On the other hand, the enhanced is the more efficient method to prevent the hourglass effect for rectangular elements. The model mesh8 × 10 gives an error less than 15% for cutting force. Moreover, the effect of element dimension on cutting force can be reduced by applying the fracture energy criterion controlled through a characteristic length to different mesh dimensions.","PeriodicalId":20663,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture","volume":"22 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75826772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-08DOI: 10.1177/09544054231194107
B. Ben Fraj, Taoufik Kamoun, H. Hentati, Mounir Trabelsi, N. Ghazouani, Mohd Ahmed
Design of experiments is a statistical approach from which an optimized number of experiments is determined. Taguchi design of experiments, applied on Erichsen tests, is chosen to be considered in this paper. The most important parameters in this forming process, Erichsen index ( IE), and maximum generated force ( Fmax), are experimentally and theoretically determined. Three input factors are selected, at diverse levels, in order to study their influence on Erichsen output results. The considered input factors are sheet thickness, punch diameter, and friction coefficient. New mathematical models which take into account the effects of these factors and their interactions are developed. Moreover, the influence of Erichsen test on the S235 steel microstructural behavior is experimentally examined as function of the sheet thickness. A good agreement between experimental and theoretical findings proves that the proposed models provide a precise prediction and an exact estimation of the Erichsen output parameters ( IE and Fmax). The efficiency of the adopted design of experiments via Taguchi method is well confirmed.
{"title":"Optimization of forming force and Erichsen index using Taguchi design of experiments: Mathematical models and experimental validation","authors":"B. Ben Fraj, Taoufik Kamoun, H. Hentati, Mounir Trabelsi, N. Ghazouani, Mohd Ahmed","doi":"10.1177/09544054231194107","DOIUrl":"https://doi.org/10.1177/09544054231194107","url":null,"abstract":"Design of experiments is a statistical approach from which an optimized number of experiments is determined. Taguchi design of experiments, applied on Erichsen tests, is chosen to be considered in this paper. The most important parameters in this forming process, Erichsen index ( IE), and maximum generated force ( Fmax), are experimentally and theoretically determined. Three input factors are selected, at diverse levels, in order to study their influence on Erichsen output results. The considered input factors are sheet thickness, punch diameter, and friction coefficient. New mathematical models which take into account the effects of these factors and their interactions are developed. Moreover, the influence of Erichsen test on the S235 steel microstructural behavior is experimentally examined as function of the sheet thickness. A good agreement between experimental and theoretical findings proves that the proposed models provide a precise prediction and an exact estimation of the Erichsen output parameters ( IE and Fmax). The efficiency of the adopted design of experiments via Taguchi method is well confirmed.","PeriodicalId":20663,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture","volume":"32 Suppl 2 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79871693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-07DOI: 10.1177/09544054231190671
Yujia Zheng, Zengshou Dong, Xiaohong Zhang, Hui Shi
Cracks due to corrosion are one of the main reasons for natural-gas pipeline leaks. Making the reliability assessment, prediction, and maintenance decision of pipelines based on measurable crack data is a central issue at present. The failure of pipelines is usually a result of the cumulative impact of multiple cracks. The interaction between adjacent cracks accelerates crack propagation, and greatly affects the degradation mechanism of pipelines. In this study, the reliability prediction and maintenance decisions were studied by considering the dependent degradation between multiple cracks in pipelines. Firstly, the initiation and propagation of pipeline cracks were modeled using a non-homogeneous Poisson process and a Gamma process, respectively. The interaction between cracks was defined to be a function of the random crack distance, which could be reflected by the change of shape parameters in the Gamma process. Secondly, the pipeline’s failure was defined as the competitive failure of the number of cracks, the maximum crack depth, and the total crack depth. The reliability prediction model of a pipeline under this failure mode was determined. A non-periodic combined maintenance policy considering both the pipeline condition and its predictive reliability was then proposed, and an optimal predictive maintenance decision model was constructed to minimize the long-term average cost rate. Finally, the effectiveness of the proposed model and policy was verified by a numerical experiment and a crack dataset of a transnational pipeline.
{"title":"Pipeline reliability assessment and predictive maintenance considering multi-crack dependent degradation","authors":"Yujia Zheng, Zengshou Dong, Xiaohong Zhang, Hui Shi","doi":"10.1177/09544054231190671","DOIUrl":"https://doi.org/10.1177/09544054231190671","url":null,"abstract":"Cracks due to corrosion are one of the main reasons for natural-gas pipeline leaks. Making the reliability assessment, prediction, and maintenance decision of pipelines based on measurable crack data is a central issue at present. The failure of pipelines is usually a result of the cumulative impact of multiple cracks. The interaction between adjacent cracks accelerates crack propagation, and greatly affects the degradation mechanism of pipelines. In this study, the reliability prediction and maintenance decisions were studied by considering the dependent degradation between multiple cracks in pipelines. Firstly, the initiation and propagation of pipeline cracks were modeled using a non-homogeneous Poisson process and a Gamma process, respectively. The interaction between cracks was defined to be a function of the random crack distance, which could be reflected by the change of shape parameters in the Gamma process. Secondly, the pipeline’s failure was defined as the competitive failure of the number of cracks, the maximum crack depth, and the total crack depth. The reliability prediction model of a pipeline under this failure mode was determined. A non-periodic combined maintenance policy considering both the pipeline condition and its predictive reliability was then proposed, and an optimal predictive maintenance decision model was constructed to minimize the long-term average cost rate. Finally, the effectiveness of the proposed model and policy was verified by a numerical experiment and a crack dataset of a transnational pipeline.","PeriodicalId":20663,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture","volume":"17 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82478128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-30DOI: 10.1177/09544054231194106
Narinder Kumar, R. Upadhyay, C. Sharma, Anupam Agrawal
The warm incremental forming process is an effective and flexible approach for forming magnesium alloy (AZ31B) sheets, which usually is difficult to deform at room temperature. However, friction increases drastically at elevated temperatures during the forming process. In order to reduce friction, liquid lubricants are generally applied on the sheet’s surface; however, the liquid lubricant usually thins out during the warm incremental forming process. To address this problem, solid lubricants such as graphite and molybdenum disulfide have been used as better alternative lubricants for forming the parts at elevated temperatures. In addition, an increase in surface roughness, either by depositing porous film or by creating micro or nanostructures, can help better the surfaces’ lubrication by solid lubricants. In this work, a facile etching method is used to treat a pre-formed sheet and solid lubricants to improve the surface quality and reduce the part’s wear during the warm incremental forming process. The combined effect of the type of solid lubricant and etching time is studied in detail. The quality of the magnesium alloy sample and its morphology before and after the forming process has been examined using various characterization tools, including a surface roughness tester, a tribometer, and scanning electron microscopy (SEM). The results reveal that the magnesium alloy sample etched for 5 min and lubricated with graphite powder showed significantly low weight loss and better surface quality. Overall, the results revealed that the etching of samples could be highly beneficial for the warm incremental forming process.
{"title":"Surface quality enhancement of warm incremental forming process using solid lubricant with varying etching period","authors":"Narinder Kumar, R. Upadhyay, C. Sharma, Anupam Agrawal","doi":"10.1177/09544054231194106","DOIUrl":"https://doi.org/10.1177/09544054231194106","url":null,"abstract":"The warm incremental forming process is an effective and flexible approach for forming magnesium alloy (AZ31B) sheets, which usually is difficult to deform at room temperature. However, friction increases drastically at elevated temperatures during the forming process. In order to reduce friction, liquid lubricants are generally applied on the sheet’s surface; however, the liquid lubricant usually thins out during the warm incremental forming process. To address this problem, solid lubricants such as graphite and molybdenum disulfide have been used as better alternative lubricants for forming the parts at elevated temperatures. In addition, an increase in surface roughness, either by depositing porous film or by creating micro or nanostructures, can help better the surfaces’ lubrication by solid lubricants. In this work, a facile etching method is used to treat a pre-formed sheet and solid lubricants to improve the surface quality and reduce the part’s wear during the warm incremental forming process. The combined effect of the type of solid lubricant and etching time is studied in detail. The quality of the magnesium alloy sample and its morphology before and after the forming process has been examined using various characterization tools, including a surface roughness tester, a tribometer, and scanning electron microscopy (SEM). The results reveal that the magnesium alloy sample etched for 5 min and lubricated with graphite powder showed significantly low weight loss and better surface quality. Overall, the results revealed that the etching of samples could be highly beneficial for the warm incremental forming process.","PeriodicalId":20663,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture","volume":"59 1","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76889806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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