. The thickness eccentricity of a pipe occurs due to manufacturing limitations and may be exacerbated by service-induced degradation mechanisms. Fracture and remaining life assessments of a cracked eccentric pipe require a solution for the crack-tip parameters, e.g., the stress intensity factors (SIFs). However, the SIFs for this problem have not been examined. This study aimed to develop SIFs for an eccentric pipe with an infinitely longitudinal crack nucleated from an inner wall at the thinnest location of the pipe cross-section subjected to internal pressure. The problem was simplified to a cracked eccentric ring in a plane-strain condition, and finite element analysis was utilized for the determination of the SIFs, which were presented in tabulated form and empirical relation. The SIFs included a wide range of configuration parameters, i.e., a thin to thick-walled pipe, a shallow to deep crack, and a concentric pipe to a pipe with moderate thickness eccentricity. The need to consider the effect of eccentricity in SIFs calculation increased when the relative thickness of a pipe decreased and the relative crack depth increased.
{"title":"Effect of Thickness Eccentricity on the Stress Intensity Factors for a Pipe with a Single Internal Radial Crack under Internal Pressure","authors":"Jirapong Kasivitamnuay, Patchanida Seenuan, Nitikorn Noraphaiphipaksa, Chaosuan Kanchanomai","doi":"10.4186/ej.2023.27.3.25","DOIUrl":"https://doi.org/10.4186/ej.2023.27.3.25","url":null,"abstract":". The thickness eccentricity of a pipe occurs due to manufacturing limitations and may be exacerbated by service-induced degradation mechanisms. Fracture and remaining life assessments of a cracked eccentric pipe require a solution for the crack-tip parameters, e.g., the stress intensity factors (SIFs). However, the SIFs for this problem have not been examined. This study aimed to develop SIFs for an eccentric pipe with an infinitely longitudinal crack nucleated from an inner wall at the thinnest location of the pipe cross-section subjected to internal pressure. The problem was simplified to a cracked eccentric ring in a plane-strain condition, and finite element analysis was utilized for the determination of the SIFs, which were presented in tabulated form and empirical relation. The SIFs included a wide range of configuration parameters, i.e., a thin to thick-walled pipe, a shallow to deep crack, and a concentric pipe to a pipe with moderate thickness eccentricity. The need to consider the effect of eccentricity in SIFs calculation increased when the relative thickness of a pipe decreased and the relative crack depth increased.","PeriodicalId":11618,"journal":{"name":"Engineering Journal","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135533283","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}
. The problem of weight functions for an edge crack in semi-infinite bilayer materials was revisited. The research aimed to develop the empirical equations for geometrical factors for reference SIFs associated with the weight functions, which covered a wider range of elastic mismatches. The weight functions in consideration covered the cases of a crack tip in a surface layer as well as in a substrate. The direct adjustment method was employed to derive the weight function coefficients. The reference SIFs for calculating the weight function coefficients were determined by finite element analysis with a systematic variation of the crack depth and the elastic mismatch parameters. The accuracies of the empirical equations for geometrical factors for the cases of a crack tip in coating and substrate were better than 1.3% and 4%, respectively. The weight functions were applied to bilayer materials with an edge crack under various crack face loading profiles. The SIFs predicted by the weight function method agreed with those from the FE method or the literature.
{"title":"Weight Functions for Edge Crack in Bilayer Material","authors":"Jirapong Kasivitamnuay, Sarita Morakul","doi":"10.4186/ej.2023.27.3.37","DOIUrl":"https://doi.org/10.4186/ej.2023.27.3.37","url":null,"abstract":". The problem of weight functions for an edge crack in semi-infinite bilayer materials was revisited. The research aimed to develop the empirical equations for geometrical factors for reference SIFs associated with the weight functions, which covered a wider range of elastic mismatches. The weight functions in consideration covered the cases of a crack tip in a surface layer as well as in a substrate. The direct adjustment method was employed to derive the weight function coefficients. The reference SIFs for calculating the weight function coefficients were determined by finite element analysis with a systematic variation of the crack depth and the elastic mismatch parameters. The accuracies of the empirical equations for geometrical factors for the cases of a crack tip in coating and substrate were better than 1.3% and 4%, respectively. The weight functions were applied to bilayer materials with an edge crack under various crack face loading profiles. The SIFs predicted by the weight function method agreed with those from the FE method or the literature.","PeriodicalId":11618,"journal":{"name":"Engineering Journal","volume":"201 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135533285","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}
. The shear strength of the adhesive bonding between slider and suspension is a vital characteristic for head gimbal assembly. The current shear test method has shown improper failure modes; therefore, a new system has been designed to improve the slider shear test. Six sigma framework was applied to redesign the slider shear test system. The finite element method confirms that new design concept is acceptable because it can yield the correct failure mode of shear test. Next, the measurement errors of the new shear test system are assessed using nested gage repeatability and reproducibility (NGR&R). NGR&R of new shear test system is less than 10% which is an adequate gage. Then, the results of simulation also confirm that decreasing of measurement error can significantly reduce the over reject rate. In conclusion, new shear test system can be effectively used to reflect the real product quality and to obtain more accurate process capability resulting from the correct failure mode of testing.
{"title":"Design and Analysis of the Slider Shear Test System Using Nested GR&R Measurement System","authors":"Santi Pumkrachang, Krisada Asawarungsaengkul, Parames Chutima","doi":"10.4186/ej.2023.27.3.11","DOIUrl":"https://doi.org/10.4186/ej.2023.27.3.11","url":null,"abstract":". The shear strength of the adhesive bonding between slider and suspension is a vital characteristic for head gimbal assembly. The current shear test method has shown improper failure modes; therefore, a new system has been designed to improve the slider shear test. Six sigma framework was applied to redesign the slider shear test system. The finite element method confirms that new design concept is acceptable because it can yield the correct failure mode of shear test. Next, the measurement errors of the new shear test system are assessed using nested gage repeatability and reproducibility (NGR&R). NGR&R of new shear test system is less than 10% which is an adequate gage. Then, the results of simulation also confirm that decreasing of measurement error can significantly reduce the over reject rate. In conclusion, new shear test system can be effectively used to reflect the real product quality and to obtain more accurate process capability resulting from the correct failure mode of testing.","PeriodicalId":11618,"journal":{"name":"Engineering Journal","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135533286","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}
. In this work, the influence of atmospheric-pressure air plasma on soil quality improvement has been studied. The practical plasma model has been designed to shape like a rake using spark plugs. The high-frequency AC high voltage has been varied at 9, 12, and 15 kV for plasma generation. The soil has been treated directly with air plasma for three consecutive days with a discharge time of 15 and 30 minutes once a day before using it for cultivation. Regarding the experimental results, air plasma significantly positively affects soil enhancement. The germination rate and length of the sprout of all the morning glory seeds cultivated in the plasma-treated soils have been higher than the one of the control group, which are up to 1.74, and 1.14 times higher than that of the control group, respectively. From the soil analysis, the Total Kjeldahl Nitrogen (TKN) content could be improved for all the plasma-treated cases. The best condition has been at 12 kV with a discharge time of 15 minutes, where the TKN has been 4.33 times greater than the one of the control group. Moreover, the pH of all the plasma-treated cases has tended to increase, resulting in more pH-balanced
{"title":"Plasma Activated Soil: A Novel Technique for Agricultural Soil Enhancement","authors":"Khanit Matra, Yottana Tanakaran, Wutthichok Sangwang, Jiraporn Promping, Suthida Theepharaksapan","doi":"10.4186/ej.2023.27.3.1","DOIUrl":"https://doi.org/10.4186/ej.2023.27.3.1","url":null,"abstract":". In this work, the influence of atmospheric-pressure air plasma on soil quality improvement has been studied. The practical plasma model has been designed to shape like a rake using spark plugs. The high-frequency AC high voltage has been varied at 9, 12, and 15 kV for plasma generation. The soil has been treated directly with air plasma for three consecutive days with a discharge time of 15 and 30 minutes once a day before using it for cultivation. Regarding the experimental results, air plasma significantly positively affects soil enhancement. The germination rate and length of the sprout of all the morning glory seeds cultivated in the plasma-treated soils have been higher than the one of the control group, which are up to 1.74, and 1.14 times higher than that of the control group, respectively. From the soil analysis, the Total Kjeldahl Nitrogen (TKN) content could be improved for all the plasma-treated cases. The best condition has been at 12 kV with a discharge time of 15 minutes, where the TKN has been 4.33 times greater than the one of the control group. Moreover, the pH of all the plasma-treated cases has tended to increase, resulting in more pH-balanced","PeriodicalId":11618,"journal":{"name":"Engineering Journal","volume":"478 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135533284","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}
. The effectiveness of modal and ultrasonic tests for monitoring the damage in precast prestressed concrete slabs was experimentally investigated. Four slabs with two different span lengths and corresponding modes of failure (interfacial shear and flexural failures) were subjected to loading steps until failure. The variations in fundamental natural frequency, damping ratio, ultrasonic pulse velocity (UPV), and ultrasonic wave attenuation in relation to the damage severity and failure mode were investigated and compared. It was observed that the natural frequency was sensitive to flexural crack development. A significant change in the damping ratio was obtained in the slabs with moderate damage. The UPV was not affected by a moderate degree of interfacial shear damage and a low degree of flexural damage; however, it was strongly related to the progression of flexural damage at the severe stage. Among the various indexes, ultrasonic wave attenuation was most sensitive to the development of damage. The method could detect interfacial-shear and flexural cracks at an early stage.
{"title":"Monitoring Damage in PC Slabs by Modal and Ultrasonic Tests","authors":"Sitthinon Kaewsawang, Wacharaphon Chaisiriniran, Poohrid Kaewngam, Piya Chotickai","doi":"10.4186/ej.2023.27.2.17","DOIUrl":"https://doi.org/10.4186/ej.2023.27.2.17","url":null,"abstract":". The effectiveness of modal and ultrasonic tests for monitoring the damage in precast prestressed concrete slabs was experimentally investigated. Four slabs with two different span lengths and corresponding modes of failure (interfacial shear and flexural failures) were subjected to loading steps until failure. The variations in fundamental natural frequency, damping ratio, ultrasonic pulse velocity (UPV), and ultrasonic wave attenuation in relation to the damage severity and failure mode were investigated and compared. It was observed that the natural frequency was sensitive to flexural crack development. A significant change in the damping ratio was obtained in the slabs with moderate damage. The UPV was not affected by a moderate degree of interfacial shear damage and a low degree of flexural damage; however, it was strongly related to the progression of flexural damage at the severe stage. Among the various indexes, ultrasonic wave attenuation was most sensitive to the development of damage. The method could detect interfacial-shear and flexural cracks at an early stage.","PeriodicalId":11618,"journal":{"name":"Engineering Journal","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135201991","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}
. Input-shaped model reference control using sliding mode design is a proven method for controlling systems with parameter variations and disturbance. However, this method has never been reported for an industrial overhead crane, which is operated under nonlinear elements such as acceleration and deceleration limits caused by inverters for driving a crane in speed control mode. The successful implementation of this method will allow the crane to be operated in “hybrid mode”, which results in the fastest response from the feedforward control technique, unity magnitude zero vibration (UMZV) and tracking performance from the feedback control. This paper shows the implementation and experimental result of the input-shaped model reference control using sliding mode design for sway suppression of an industrial overhead crane. The control scheme was implemented on an industrial grade 1-ton overhead crane using a PLC and inverters. The experiments compared the control results of the UMZV and the presented control scheme on the industrial overhead crane in the cases that the system parameters are known and uncertain. When the parameters are uncertain, the presented method, with the feedback elements, provided the advantage of reducing residual vibration, while keeping the benefits of the UMZV performance.
{"title":"Input-Shaped Model Reference Control Using Sliding Mode Design for Sway Suppression of An Industrial Overhead Crane","authors":"Nattapong Suksabai, Ittichote Chuckpaiwong","doi":"10.4186/ej.2023.27.2.1","DOIUrl":"https://doi.org/10.4186/ej.2023.27.2.1","url":null,"abstract":". Input-shaped model reference control using sliding mode design is a proven method for controlling systems with parameter variations and disturbance. However, this method has never been reported for an industrial overhead crane, which is operated under nonlinear elements such as acceleration and deceleration limits caused by inverters for driving a crane in speed control mode. The successful implementation of this method will allow the crane to be operated in “hybrid mode”, which results in the fastest response from the feedforward control technique, unity magnitude zero vibration (UMZV) and tracking performance from the feedback control. This paper shows the implementation and experimental result of the input-shaped model reference control using sliding mode design for sway suppression of an industrial overhead crane. The control scheme was implemented on an industrial grade 1-ton overhead crane using a PLC and inverters. The experiments compared the control results of the UMZV and the presented control scheme on the industrial overhead crane in the cases that the system parameters are known and uncertain. When the parameters are uncertain, the presented method, with the feedback elements, provided the advantage of reducing residual vibration, while keeping the benefits of the UMZV performance.","PeriodicalId":11618,"journal":{"name":"Engineering Journal","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135201990","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}
. This research focused on the cycle time reduction of the automotive audio monitor base frame assembly process in a small electronic parts manufacturing company through the application of the Lean and ergonomics approaches. In recent years, the company has faced the problem of not being able to assemble products to meet customer s’ orders due to the need to lay off some skilled workers to survive during the COVID-19 crisis. This resulted in a severe loss in customer goodwill and confidence. The improvement process began with a review of the current assembly workflow as well as the detailed hand and arm movements of workers. Then, to determine the as-is operational procedure and average cycle time of the assembly process, a series of videos were recorded and playback in slow motion. Lean management techniques, such as 7 wastes and 5 Whys, were employed to identify the potential root causes of the problems. In addition, the ECRS (eliminate, combine, rearrange and simplify) techniques of Lean management in combination with the ergonomics principles were applied to modify the operational procedure and the postures and movements of the workers. The workspace and environmental conditions were also adjusted to enable more efficient workers’ operations. The result demonstrated that such an approach could help reduce the cycle time of the assembly process to achieve the predefined target.
{"title":"Practical Implementation of Lean Management Techniques and Ergonomic Consideration to Improve Manual Assembly Process During the COVID-19 Crisis","authors":"Nattapat Suranuntchai, Parames Chutima","doi":"10.4186/ej.2023.27.2.29","DOIUrl":"https://doi.org/10.4186/ej.2023.27.2.29","url":null,"abstract":". This research focused on the cycle time reduction of the automotive audio monitor base frame assembly process in a small electronic parts manufacturing company through the application of the Lean and ergonomics approaches. In recent years, the company has faced the problem of not being able to assemble products to meet customer s’ orders due to the need to lay off some skilled workers to survive during the COVID-19 crisis. This resulted in a severe loss in customer goodwill and confidence. The improvement process began with a review of the current assembly workflow as well as the detailed hand and arm movements of workers. Then, to determine the as-is operational procedure and average cycle time of the assembly process, a series of videos were recorded and playback in slow motion. Lean management techniques, such as 7 wastes and 5 Whys, were employed to identify the potential root causes of the problems. In addition, the ECRS (eliminate, combine, rearrange and simplify) techniques of Lean management in combination with the ergonomics principles were applied to modify the operational procedure and the postures and movements of the workers. The workspace and environmental conditions were also adjusted to enable more efficient workers’ operations. The result demonstrated that such an approach could help reduce the cycle time of the assembly process to achieve the predefined target.","PeriodicalId":11618,"journal":{"name":"Engineering Journal","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135201992","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}
. In sugar refining, pulsed bed adsorption columns are used to remove colorants in sugar syrup. The pulsed bed adsorption column is a cyclic steady state operation that maximize the adsorbent utilization due to the increased driving force but requires special attention on control and optimization. The modelling and feedforward control of the pulsed bed adsorption columns is investigated in this article. The aim of this research is to develop the mathematical model of pulsed bed adsorption column by using the parameters obtained from breakthrough of fixed bed column and to investigate the optimum cycle time at different colorant concentrations in feed sugar syrup. The analysis showed that the optimum cycle time of pulsed bed adsorption column depended on feed flow rates and the colorant concentrations in feed sugar syrup. As the feed flow rate and colorant concentration increased, the optimum cycle time decreased. The feedforward control successfully compensated the effects of disturbances from colorant concentrations in feed syrup for both step and cosine functions and yielded the sugar syrup that met its specification.
{"title":"Modelling and Feedforward Control of Pulsed Bed Adsorption Column for Colorant Removal in Sugar Syrup","authors":"Chanya Plangklang, Terasut Sookkumnerd","doi":"10.4186/ej.2023.27.1.29","DOIUrl":"https://doi.org/10.4186/ej.2023.27.1.29","url":null,"abstract":". In sugar refining, pulsed bed adsorption columns are used to remove colorants in sugar syrup. The pulsed bed adsorption column is a cyclic steady state operation that maximize the adsorbent utilization due to the increased driving force but requires special attention on control and optimization. The modelling and feedforward control of the pulsed bed adsorption columns is investigated in this article. The aim of this research is to develop the mathematical model of pulsed bed adsorption column by using the parameters obtained from breakthrough of fixed bed column and to investigate the optimum cycle time at different colorant concentrations in feed sugar syrup. The analysis showed that the optimum cycle time of pulsed bed adsorption column depended on feed flow rates and the colorant concentrations in feed sugar syrup. As the feed flow rate and colorant concentration increased, the optimum cycle time decreased. The feedforward control successfully compensated the effects of disturbances from colorant concentrations in feed syrup for both step and cosine functions and yielded the sugar syrup that met its specification.","PeriodicalId":11618,"journal":{"name":"Engineering Journal","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135440112","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 : 2020-03-31DOI: 10.62913/engj.v57i1.1158
M. Denavit, William P. Jacobs, T. Helwig
The design of floor and roof framing members is typically controlled by flexural demands; however, if a member serves as a chord or collector it can also be subjected to significant axial compression. Continuous restraint provided by the floor or roof diaphragm is commonly assumed in design to provide adequate bracing of connected wide-flange members against minor-axis flexural buckling; however, these members are still susceptible to major-axis flexural buckling and potentially to torsional buckling about a constrained axis located at the top flange. In addition to the lateral restraint, floor and roof decking systems can also provide continuous torsional restraint through their flexural stiffness and strength. This restraint can be used to increase the calculated constrained-axis torsional buckling strength or inhibit the mode altogether. In this paper, the specific case of a wide-flange steel beam-column with both lateral and torsional restraint located at the top flange is investigated and torsional bracing requirements are derived. The focus of the study is on continuous torsional bracing and its effect on the constrained-axis torsional buckling mode. The requirements are illustrated through a design example and a parametric study is performed examining typical floor and roof decking system configurations, identifying cases where improved design efficiency can be achieved.
{"title":"Continuous Bracing Requirements for Constrained-Axis Torsional Buckling","authors":"M. Denavit, William P. Jacobs, T. Helwig","doi":"10.62913/engj.v57i1.1158","DOIUrl":"https://doi.org/10.62913/engj.v57i1.1158","url":null,"abstract":"The design of floor and roof framing members is typically controlled by flexural demands; however, if a member serves as a chord or collector it can also be subjected to significant axial compression. Continuous restraint provided by the floor or roof diaphragm is commonly assumed in design to provide adequate bracing of connected wide-flange members against minor-axis flexural buckling; however, these members are still susceptible to major-axis flexural buckling and potentially to torsional buckling about a constrained axis located at the top flange. In addition to the lateral restraint, floor and roof decking systems can also provide continuous torsional restraint through their flexural stiffness and strength. This restraint can be used to increase the calculated constrained-axis torsional buckling strength or inhibit the mode altogether. In this paper, the specific case of a wide-flange steel beam-column with both lateral and torsional restraint located at the top flange is investigated and torsional bracing requirements are derived. The focus of the study is on continuous torsional bracing and its effect on the constrained-axis torsional buckling mode. The requirements are illustrated through a design example and a parametric study is performed examining typical floor and roof decking system configurations, identifying cases where improved design efficiency can be achieved.","PeriodicalId":11618,"journal":{"name":"Engineering Journal","volume":" 23","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141219822","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 : 2020-03-31DOI: 10.62913/engj.v57i1.1160
James A. Swanson, G. Rassati, Chad M. Larson
This paper presents a reliability and probability study focusing on connections using relatively short bolts that in a companion paper have been shown to have the potential to have been designed with threads excluded from the shear plane and then subsequently installed with the threads not excluded from the shear plane. After an introduction outlining the background of the shear strength and associated design of joints in various editions of the AISC Specification, the paper presents a structural reliability analysis as well as a probability study using Monte Carlo simulations, and then finally a discussion of additional considerations and mitigating factors associated with this potential problem. Calculated reliability coefficients and probabilities of failure are tabulated for joints using two diameter groups of 120-ksi bolts (from ? in. to 1 in. and from 1? in. to 1¼ in.) and for joints using 150-ksi bolts. The paper provides an evaluation of the reliability of joints with bolts that have been designed with the threads excluded from the shear plane but installed with the threads not excluded from the shear plane. Although it is recommended that future designs involving short bolts be based on the assumption that the threads are not excluded from the shear plane, this study provides a measure of the reliability of structures that have already been constructed with bolts designed assuming that the threads were excluded but installed with the threads not excluded. The results show that the reliability of joints in this class is dependent on the grade and size of the bolts used, on the length of the joint, and on which edition of the AISC Specification was used for design. It was found that some joints in this class still meet the AISC target reliability for connections, and that many joints meet the AISC target reliability for members.
{"title":"A Reliability Study of Joints with Bolts Designed with Threads Excluded but Installed with Threads Not Excluded","authors":"James A. Swanson, G. Rassati, Chad M. Larson","doi":"10.62913/engj.v57i1.1160","DOIUrl":"https://doi.org/10.62913/engj.v57i1.1160","url":null,"abstract":"This paper presents a reliability and probability study focusing on connections using relatively short bolts that in a companion paper have been shown to have the potential to have been designed with threads excluded from the shear plane and then subsequently installed with the threads not excluded from the shear plane. After an introduction outlining the background of the shear strength and associated design of joints in various editions of the AISC Specification, the paper presents a structural reliability analysis as well as a probability study using Monte Carlo simulations, and then finally a discussion of additional considerations and mitigating factors associated with this potential problem. Calculated reliability coefficients and probabilities of failure are tabulated for joints using two diameter groups of 120-ksi bolts (from ? in. to 1 in. and from 1? in. to 1¼ in.) and for joints using 150-ksi bolts. The paper provides an evaluation of the reliability of joints with bolts that have been designed with the threads excluded from the shear plane but installed with the threads not excluded from the shear plane. Although it is recommended that future designs involving short bolts be based on the assumption that the threads are not excluded from the shear plane, this study provides a measure of the reliability of structures that have already been constructed with bolts designed assuming that the threads were excluded but installed with the threads not excluded. The results show that the reliability of joints in this class is dependent on the grade and size of the bolts used, on the length of the joint, and on which edition of the AISC Specification was used for design. It was found that some joints in this class still meet the AISC target reliability for connections, and that many joints meet the AISC target reliability for members.","PeriodicalId":11618,"journal":{"name":"Engineering Journal","volume":" 42","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141219818","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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