Jian-wei Zhang, Guoguan Lan, Shui-mei Chen, Hua-nan Xu, Zai-lin Yang
An anisotropic bi-material interface with a circular hollow and a crack was used to explore the scattering of SH waves using complex variables and Green's function techniques. A horizontal interface in a bi-material media forms an elastic anisotropic half-space with a circular cavity and a linear crack, whereas the other half-space is an elastic isotropic half-space. The Green's function approach is used to derive the relevant Green's functions, which are then used in the “crack division” procedure to create a crack. During the joining of the two pieces, unknown anti-plane forces are applied to the horizontal surfaces to ensure the interface maintains its continuity criteria. For weakly singular integral equations, Fredholm integral equations are inferred and solved using the direct discrete technique. The simulation results were represented graphically to show how different parameters affect the influence of dynamic stress concentration factors around the cavity and dynamic stress intensity factors toward the crack tip. For example, a cavity's wave number and angle of incidence, as well as the distance between the cavity's center and its horizontal interface and its radius, are all elements that must be taken into consideration.
{"title":"Interaction of circular cavity and crack near anisotropic bi-material interface under SH-waves incidence","authors":"Jian-wei Zhang, Guoguan Lan, Shui-mei Chen, Hua-nan Xu, Zai-lin Yang","doi":"10.1093/jom/ufac050","DOIUrl":"https://doi.org/10.1093/jom/ufac050","url":null,"abstract":"An anisotropic bi-material interface with a circular hollow and a crack was used to explore the scattering of SH waves using complex variables and Green's function techniques. A horizontal interface in a bi-material media forms an elastic anisotropic half-space with a circular cavity and a linear crack, whereas the other half-space is an elastic isotropic half-space. The Green's function approach is used to derive the relevant Green's functions, which are then used in the “crack division” procedure to create a crack. During the joining of the two pieces, unknown anti-plane forces are applied to the horizontal surfaces to ensure the interface maintains its continuity criteria. For weakly singular integral equations, Fredholm integral equations are inferred and solved using the direct discrete technique. The simulation results were represented graphically to show how different parameters affect the influence of dynamic stress concentration factors around the cavity and dynamic stress intensity factors toward the crack tip. For example, a cavity's wave number and angle of incidence, as well as the distance between the cavity's center and its horizontal interface and its radius, are all elements that must be taken into consideration.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61542307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Enling Tang, Zhen Zhang, Chuang Chen, Yafei Han, Mengzhou Chang, K. Guo, Liping He
In the process of underwater motion, the trajectory of the projectile will be greatly disturbed due to the complicated underwater environment and cavitation effect. In order to study the effect of the ice water mixture on projectile motion, the experiments of a titanium alloy slender body with a truncated conical and plat warhead passing through ice and water mixture have been performed by using a one-stage light gas gun loading system, an overpressure sensor measurement system and a high-speed camera acquisition system in this paper. The experimental results show that the volume of the cavity generated by the slender body with a small length-to-diameter ratio is larger, and the slender body deflects in the process of movement. For a slender body with a large length-to-diameter ratio, the cavity formed is closer to the central axis and the maximum radial size of the cavity. No matter the warhead shapes are truncated conical or plat warhead, the diameter and lasting time of the cavity increase with the increase of the slender body's velocities. Under the condition that the length-to-diameter ratio and the velocity of the slender bodies are similar, the overall evolutionary trend of the overpressure generated by two kinds of slender bodies is similar. But the fluctuation range of the overpressure amplitude of the plat warhead is small, the curve oscillation amplitude of the adjacent time is large and the peak value of the overpressure for the truncated conical warhead is large. Under the same ratio of length to diameter, the velocity has no obvious influence on the trajectory of the slender body after hitting the ice particles. When the slender body collides with ice particles, the deflection angle of its trajectory is larger than that of impacting on the edge of ice particles. When the slender body collides with the ice particles, the interaction between the ice particles and the slender body is large, and the deflection angle of the slender body is larger after impact.
{"title":"Dynamic response of slender body passing through ice and water mixture at high velocity","authors":"Enling Tang, Zhen Zhang, Chuang Chen, Yafei Han, Mengzhou Chang, K. Guo, Liping He","doi":"10.1093/jom/ufac016","DOIUrl":"https://doi.org/10.1093/jom/ufac016","url":null,"abstract":"In the process of underwater motion, the trajectory of the projectile will be greatly disturbed due to the complicated underwater environment and cavitation effect. In order to study the effect of the ice water mixture on projectile motion, the experiments of a titanium alloy slender body with a truncated conical and plat warhead passing through ice and water mixture have been performed by using a one-stage light gas gun loading system, an overpressure sensor measurement system and a high-speed camera acquisition system in this paper. The experimental results show that the volume of the cavity generated by the slender body with a small length-to-diameter ratio is larger, and the slender body deflects in the process of movement. For a slender body with a large length-to-diameter ratio, the cavity formed is closer to the central axis and the maximum radial size of the cavity. No matter the warhead shapes are truncated conical or plat warhead, the diameter and lasting time of the cavity increase with the increase of the slender body's velocities. Under the condition that the length-to-diameter ratio and the velocity of the slender bodies are similar, the overall evolutionary trend of the overpressure generated by two kinds of slender bodies is similar. But the fluctuation range of the overpressure amplitude of the plat warhead is small, the curve oscillation amplitude of the adjacent time is large and the peak value of the overpressure for the truncated conical warhead is large. Under the same ratio of length to diameter, the velocity has no obvious influence on the trajectory of the slender body after hitting the ice particles. When the slender body collides with ice particles, the deflection angle of its trajectory is larger than that of impacting on the edge of ice particles. When the slender body collides with the ice particles, the interaction between the ice particles and the slender body is large, and the deflection angle of the slender body is larger after impact.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61539775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The article compares two different electrical rectifications employed by a piezoelectric harvester array. The first type consists of parallel connection of harvesters followed by an AC–DC full-bridge rectifier for overall electrical rectification. The second type allows for respective electrical rectification of each individual harvester, and then connecting them all in parallel. The former exhibits stronger electromechanical coupling effect for enhancing output power. The latter is capable of avoiding charge cancelation for improving bandwidth. The analysis of the electromechanical response of these two types is provided with full derivations for the second case. The predictions of displacement and output power are compared with the experiment and the results show good agreement. Two recommendations are offered from the present studies. First, suppose the power dissipations due to voltage gaps across the rectifiers are insignificant compared with the amount of output power realized by each individual harvester. The piezoelectric harvester array with respective electrical rectification exhibits better performance than that with the overall rectification from the broadband point of view at the cost of reducing peak power. On the contrary, if the amount of power dissipations can not be neglected or the harvester exhibits the strongly coupled electromechanical response, it is recommended to employ the harvester array allowing the mixed parallel/series connections switched by DPDT (Double-Pole Double-Throw). The array of the mixed type with overall electrical rectification exhibits performance significantly outperforming the array with respective electrical rectification from the point of view of broadband and power enhancement.
{"title":"Comparison between overall and respective electrical rectifications in array of piezoelectric energy harvesting","authors":"I. Lien, Y. Lo, S. Chiu, Y. C. Shu","doi":"10.1093/jom/ufac039","DOIUrl":"https://doi.org/10.1093/jom/ufac039","url":null,"abstract":"The article compares two different electrical rectifications employed by a piezoelectric harvester array. The first type consists of parallel connection of harvesters followed by an AC–DC full-bridge rectifier for overall electrical rectification. The second type allows for respective electrical rectification of each individual harvester, and then connecting them all in parallel. The former exhibits stronger electromechanical coupling effect for enhancing output power. The latter is capable of avoiding charge cancelation for improving bandwidth. The analysis of the electromechanical response of these two types is provided with full derivations for the second case. The predictions of displacement and output power are compared with the experiment and the results show good agreement. Two recommendations are offered from the present studies. First, suppose the power dissipations due to voltage gaps across the rectifiers are insignificant compared with the amount of output power realized by each individual harvester. The piezoelectric harvester array with respective electrical rectification exhibits better performance than that with the overall rectification from the broadband point of view at the cost of reducing peak power. On the contrary, if the amount of power dissipations can not be neglected or the harvester exhibits the strongly coupled electromechanical response, it is recommended to employ the harvester array allowing the mixed parallel/series connections switched by DPDT (Double-Pole Double-Throw). The array of the mixed type with overall electrical rectification exhibits performance significantly outperforming the array with respective electrical rectification from the point of view of broadband and power enhancement.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61541696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Takuya Terahara, T. Kuraishi, K. Takizawa, T. Tezduyar
In this second part of a two-part article, we provide an overview of the heart valve flow analyses conducted with boundary layer and contact representation, made possible with the space–time (ST) computational methods described in the first part. With these ST methods, we are able to represent the boundary layers near moving solid surfaces, including the valve leaflet surfaces, with the accuracy one gets from moving-mesh methods and without the need for leaving a mesh protection gap between the surfaces coming into contact. The challenge of representing the contact between the leaflets without giving up on high-resolution flow representation near the leaflet surfaces has been overcome. The other challenges that have been overcome include the complexities of a near-actual valve geometry, having in the computational model a left ventricle with an anatomically realistic motion and an aorta from CT scans and maintaining the flow stability at the inflow of the ventricle-valve-aorta sequence, where we have a traction boundary condition during part of the cardiac cycle.
{"title":"Computational flow analysis with boundary layer and contact representation: II. Heart valve flow with leaflet contact","authors":"Takuya Terahara, T. Kuraishi, K. Takizawa, T. Tezduyar","doi":"10.1093/jom/ufac013","DOIUrl":"https://doi.org/10.1093/jom/ufac013","url":null,"abstract":"In this second part of a two-part article, we provide an overview of the heart valve flow analyses conducted with boundary layer and contact representation, made possible with the space–time (ST) computational methods described in the first part. With these ST methods, we are able to represent the boundary layers near moving solid surfaces, including the valve leaflet surfaces, with the accuracy one gets from moving-mesh methods and without the need for leaving a mesh protection gap between the surfaces coming into contact. The challenge of representing the contact between the leaflets without giving up on high-resolution flow representation near the leaflet surfaces has been overcome. The other challenges that have been overcome include the complexities of a near-actual valve geometry, having in the computational model a left ventricle with an anatomically realistic motion and an aorta from CT scans and maintaining the flow stability at the inflow of the ventricle-valve-aorta sequence, where we have a traction boundary condition during part of the cardiac cycle.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61539572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Davide D’Angella, S. Kollmannsberger, A. Reali, E. Rank, T. Hughes
The finite element method is classically based on nodal Lagrange basis functions defined on conforming meshes. In this context, total reaction forces are commonly computed from the so-called “nodal forces”, yielding higher accuracy and convergence rates than reactions obtained from the differentiated primal solution (“direct” method). The finite cell method and isogeometric analysis promise to improve the interoperability of computer-aided design and computer-aided engineering, enabling a direct approach to the numerical simulation of trimmed geometries. However, body-unfitted meshes preclude the use of classic nodal reaction algorithms. This work shows that the direct method can perform particularly poorly for immersed methods. Instead, conservative reactions can be obtained from equilibrium expressions given by the weak problem formulation, yielding superior accuracy and convergence rates typical of nodal reactions. This approach is also extended to non-interpolatory basis functions, such as the (truncated) hierarchical B-splines.
{"title":"An accurate strategy for computing reaction forces and fluxes on trimmed locally refined meshes","authors":"Davide D’Angella, S. Kollmannsberger, A. Reali, E. Rank, T. Hughes","doi":"10.1093/jom/ufac006","DOIUrl":"https://doi.org/10.1093/jom/ufac006","url":null,"abstract":"The finite element method is classically based on nodal Lagrange basis functions defined on conforming meshes. In this context, total reaction forces are commonly computed from the so-called “nodal forces”, yielding higher accuracy and convergence rates than reactions obtained from the differentiated primal solution (“direct” method). The finite cell method and isogeometric analysis promise to improve the interoperability of computer-aided design and computer-aided engineering, enabling a direct approach to the numerical simulation of trimmed geometries. However, body-unfitted meshes preclude the use of classic nodal reaction algorithms. This work shows that the direct method can perform particularly poorly for immersed methods. Instead, conservative reactions can be obtained from equilibrium expressions given by the weak problem formulation, yielding superior accuracy and convergence rates typical of nodal reactions. This approach is also extended to non-interpolatory basis functions, such as the (truncated) hierarchical B-splines.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":"54 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61539360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Weight functions are provided for calculating the stress intensity factors for collinear cracks in an infinite anisotropic elastic plate. The number of cracks as well as the length of the cracks are arbitrary. The weight functions are for crack-face loading, which may be non-self-equilibrium. It is shown that for self-equilibrium loading, the weight functions are independent of elastic constants. For non-self-equilibrium loading, however, an additional constant term that is material-dependent appears.
{"title":"Weight functions for an array of collinear cracks in an infinite anisotropic elastic plate","authors":"Kuang-Chong Wu, Shyh-Haur Chen","doi":"10.1093/jom/ufac011","DOIUrl":"https://doi.org/10.1093/jom/ufac011","url":null,"abstract":"Weight functions are provided for calculating the stress intensity factors for collinear cracks in an infinite anisotropic elastic plate. The number of cracks as well as the length of the cracks are arbitrary. The weight functions are for crack-face loading, which may be non-self-equilibrium. It is shown that for self-equilibrium loading, the weight functions are independent of elastic constants. For non-self-equilibrium loading, however, an additional constant term that is material-dependent appears.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61539463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yukun Li, Longsheng Wang, S. Zhao, Jinglong Chang, Keren Shen, Shanyao Wang, Xiaojian Cao, Yixuan Wang
Excessive residual stress of the girth weld in pipes will directly damage the pipe strength during its operation. Accurate measurement and effective reduction of the residual stress can ensure the safety of natural gas pipes during their service. In this paper, an X80-type large-diameter natural gas pipe section with girth welds is taken as the research object. The coercive force method is used to characterize the residual stress of the girth weld and its surroundings, and then the distribution law of the residual stress of the girth weld and its surroundings is obtained based on the measurement results of the Blind-hole method; the ultrasonic impact method was used to reduce the girth weld residual stress, and the effect of the ultrasonic impact method on the residual stress reduction was studied by comparing changes of the distribution characteristics of the coercive force in the girth weld and its surroundings before and after the residual stress reduction in the natural gas pipes. Lastly, the in-situ test specimen is made to carry out the uniaxial tensile test so as to study the effect of the ultrasonic impact method on the tensile mechanical properties of pipe welds. This study clarifies the influence law of the ultrasonic impact on the mechanical properties of weld toe materials, and provided technical theoretical guidance for the reduction of field residual stress in natural gas pipes.
{"title":"Research on reduction of residual stress in girth welds of large-diameter natural gas pipes by ultrasonic","authors":"Yukun Li, Longsheng Wang, S. Zhao, Jinglong Chang, Keren Shen, Shanyao Wang, Xiaojian Cao, Yixuan Wang","doi":"10.1093/jom/ufac038","DOIUrl":"https://doi.org/10.1093/jom/ufac038","url":null,"abstract":"Excessive residual stress of the girth weld in pipes will directly damage the pipe strength during its operation. Accurate measurement and effective reduction of the residual stress can ensure the safety of natural gas pipes during their service. In this paper, an X80-type large-diameter natural gas pipe section with girth welds is taken as the research object. The coercive force method is used to characterize the residual stress of the girth weld and its surroundings, and then the distribution law of the residual stress of the girth weld and its surroundings is obtained based on the measurement results of the Blind-hole method; the ultrasonic impact method was used to reduce the girth weld residual stress, and the effect of the ultrasonic impact method on the residual stress reduction was studied by comparing changes of the distribution characteristics of the coercive force in the girth weld and its surroundings before and after the residual stress reduction in the natural gas pipes. Lastly, the in-situ test specimen is made to carry out the uniaxial tensile test so as to study the effect of the ultrasonic impact method on the tensile mechanical properties of pipe welds. This study clarifies the influence law of the ultrasonic impact on the mechanical properties of weld toe materials, and provided technical theoretical guidance for the reduction of field residual stress in natural gas pipes.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61541371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
It is very important for the safe production of sand producing oil and gas wells to make clear the erosion law of sand control screen pipe. The experiment of erosion law of metal mesh under two working conditions of blockage and non-blockage was carried out with jet erosion experimental device. The influencing factor of solid mass fraction (0.3%, 0.5%, and 0.8%), aperture velocity (1.5 m/s, 4 m/s, and 6 m/s) and particle size (20 μm, 54 μm, and 74 μm) on the erosion rate of metal mesh was analyzed. The results show that the mass loss of screen increases with the increase of solid mass fraction, aperture velocity and particle size, and the change law of single and double screens is consistent; under the condition of incomplete blockage, the mass loss of screen increases exponentially with the flow rate; under the condition of complete blockage, the balance flow rate of screen decreases with the increase of pressure difference when the pressure difference between inlet and outlet of screen is kept constant. In addition, the mass loss increases with the increase of pressure difference; in addition, the scanning electron microscope results of the erosion screen show that the erosion wear of the screen under the non-blocking condition is much less than that under the blocking condition, which is because the gap between the weft wires of the screen is blocked by particles, resulting in the rapid increase of the local aperture velocity of the screen, thus accelerating the local erosion wear of the screen.
{"title":"Experimental study on erosion and wear law of metal screen under spraying condition","authors":"Ruomeng Ying, Xuankang Zhao, Baocheng Shi, Lijuan Wu, X. Zhang, Ziheng Jiang, Xiaochi Guo","doi":"10.1093/jom/ufac004","DOIUrl":"https://doi.org/10.1093/jom/ufac004","url":null,"abstract":"It is very important for the safe production of sand producing oil and gas wells to make clear the erosion law of sand control screen pipe. The experiment of erosion law of metal mesh under two working conditions of blockage and non-blockage was carried out with jet erosion experimental device. The influencing factor of solid mass fraction (0.3%, 0.5%, and 0.8%), aperture velocity (1.5 m/s, 4 m/s, and 6 m/s) and particle size (20 μm, 54 μm, and 74 μm) on the erosion rate of metal mesh was analyzed. The results show that the mass loss of screen increases with the increase of solid mass fraction, aperture velocity and particle size, and the change law of single and double screens is consistent; under the condition of incomplete blockage, the mass loss of screen increases exponentially with the flow rate; under the condition of complete blockage, the balance flow rate of screen decreases with the increase of pressure difference when the pressure difference between inlet and outlet of screen is kept constant. In addition, the mass loss increases with the increase of pressure difference; in addition, the scanning electron microscope results of the erosion screen show that the erosion wear of the screen under the non-blocking condition is much less than that under the blocking condition, which is because the gap between the weft wires of the screen is blocked by particles, resulting in the rapid increase of the local aperture velocity of the screen, thus accelerating the local erosion wear of the screen.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61539166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The leakage of pipelines will cause serious harm to the human living environment. To meet the safety assessment requirement for pipelines, a pipeline burst pressure prediction method based on a parametric model is proposed. The parameters of the model include defect size, pipeline size and material properties. First, the relationship between the defect size and the burst pressure was studied by finite element analysis, and the parametric model was deduced according to the analysis results. Second, the undetermined coefficients of the model were obtained using the improved genetic algorithm. Last, comparisons of the test burst pressures with those predicted by the proposed model and three standard assessment methods were carried out. The results show that the predicted model is more reliable than the existing pipeline assessment codes.
{"title":"Research on a model-based burst pressure prediction method for pipelines with corrosion defects","authors":"Hongming Zhou, Peiyuan Li, Longfei Wu","doi":"10.1093/jom/ufac024","DOIUrl":"https://doi.org/10.1093/jom/ufac024","url":null,"abstract":"The leakage of pipelines will cause serious harm to the human living environment. To meet the safety assessment requirement for pipelines, a pipeline burst pressure prediction method based on a parametric model is proposed. The parameters of the model include defect size, pipeline size and material properties. First, the relationship between the defect size and the burst pressure was studied by finite element analysis, and the parametric model was deduced according to the analysis results. Second, the undetermined coefficients of the model were obtained using the improved genetic algorithm. Last, comparisons of the test burst pressures with those predicted by the proposed model and three standard assessment methods were carried out. The results show that the predicted model is more reliable than the existing pipeline assessment codes.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61540091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The jaw coupling with a flexible spacer is frequently used in the torque transmission between shafts with misalignment for machinery. Its torsional stiffness and limit torque closely determine the operational capacity and the dynamic characteristics of the system because the coupling is usually the most flexible link in the driving chain. In this study, the optimal design of a jaw coupling with an elastomeric spacer was investigated using the Taguchi method by considering four design factors: the tightening method of the clamping bolts, the tightening torque of the clamping bolts, the hardness of the thermoplastic polyether ester elastomer spacer and the installation angle between the two end blocks of the coupling. All specimens were tested by using an in-house torsion tester to record the torque-angular deformation responses. The results showed good reliability and repeatability, with a coefficient of variance within 5%. Spacer's hardness was found to be the most significant factor regarding the torsional stiffness, while the magnitude of the clamping torque had the most critical role in the limit torque. The estimation formulae for the torsional stiffness and limit torque of the jaw coupling were obtained by using the statistical regression of the measured data, respectively. Both formulae predicted the performance of the optimal designs within 5% of error compared to the confirmation tests.
{"title":"An experimental study on the torsional stiffness and limit torque of a jaw coupling with consideration of spacer's hardness and installation methods","authors":"Chih-Ming Chen, Huey-Ling Chang, Chun-Ying Lee","doi":"10.1093/jom/ufac018","DOIUrl":"https://doi.org/10.1093/jom/ufac018","url":null,"abstract":"The jaw coupling with a flexible spacer is frequently used in the torque transmission between shafts with misalignment for machinery. Its torsional stiffness and limit torque closely determine the operational capacity and the dynamic characteristics of the system because the coupling is usually the most flexible link in the driving chain. In this study, the optimal design of a jaw coupling with an elastomeric spacer was investigated using the Taguchi method by considering four design factors: the tightening method of the clamping bolts, the tightening torque of the clamping bolts, the hardness of the thermoplastic polyether ester elastomer spacer and the installation angle between the two end blocks of the coupling. All specimens were tested by using an in-house torsion tester to record the torque-angular deformation responses. The results showed good reliability and repeatability, with a coefficient of variance within 5%. Spacer's hardness was found to be the most significant factor regarding the torsional stiffness, while the magnitude of the clamping torque had the most critical role in the limit torque. The estimation formulae for the torsional stiffness and limit torque of the jaw coupling were obtained by using the statistical regression of the measured data, respectively. Both formulae predicted the performance of the optimal designs within 5% of error compared to the confirmation tests.","PeriodicalId":50136,"journal":{"name":"Journal of Mechanics","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61540093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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