Pub Date : 2021-10-01DOI: 10.12989/CAC.2021.28.4.347
Y. Haryanto, Hsuan-Teh Hu, A. Han, F. Hsiao, Chrang-Jen Teng, B. A. Hidayat, Laurencius Nugroho
The application of Near Surface Mounted (NSM) method to strengthen reinforced concrete (RC) members in flexure through the use of Fiber Reinforced Polymer (FRP) rods has become a subject of interest to designers and researchers over the past few years. This technique has been extensively applied, and there is still a need for more experiments, analytical, and numerical studies to determine the effects of their parameters on the flexural performance of RC members. Therefore, a detailed 3D nonlinear finite element (FE) numerical model was developed in this study to predict the load-carrying capacity and the response of RC T-beams strengthened in the negative moment region accurately through the use of NSM FRP rods at different depth of embedment which are placed under three-point bending loading. The model was, however, designed with due consideration for the nonlinear constitutive material properties of concrete, yielding of steel reinforcement, NSM rods, and cohesive behaviors to simulate the contact between two neighboring materials. Moreover, the findings of the numerical simulations were compared with those from the experiments by other investigators which involve two specimens strengthened with NSM FRP rods added to one unstrengthened control specimen. The results, however, showed that the mid-span deflection responses of the predicted FE were in line with the corresponding data from the experiment for all the flexural loading stages. This was followed by the use of the validated FE models to analyze the effect of several properties of the FRP materials to provide more information than the limited experimental data available. It was discovered that the FE model developed is appropriate to be applied practically and economically with more focus on the parametric studies based on design to precisely model and analyze flexural negative moment strengthening for the RC members through the use of NSM FRP rods.
{"title":"Numerical investigation on RC T-beams strengthened in the negative moment region using NSM FRP rods at various depth of embedment","authors":"Y. Haryanto, Hsuan-Teh Hu, A. Han, F. Hsiao, Chrang-Jen Teng, B. A. Hidayat, Laurencius Nugroho","doi":"10.12989/CAC.2021.28.4.347","DOIUrl":"https://doi.org/10.12989/CAC.2021.28.4.347","url":null,"abstract":"The application of Near Surface Mounted (NSM) method to strengthen reinforced concrete (RC) members in flexure through the use of Fiber Reinforced Polymer (FRP) rods has become a subject of interest to designers and researchers over the past few years. This technique has been extensively applied, and there is still a need for more experiments, analytical, and numerical studies to determine the effects of their parameters on the flexural performance of RC members. Therefore, a detailed 3D nonlinear finite element (FE) numerical model was developed in this study to predict the load-carrying capacity and the response of RC T-beams strengthened in the negative moment region accurately through the use of NSM FRP rods at different depth of embedment which are placed under three-point bending loading. The model was, however, designed with due consideration for the nonlinear constitutive material properties of concrete, yielding of steel reinforcement, NSM rods, and cohesive behaviors to simulate the contact between two neighboring materials. Moreover, the findings of the numerical simulations were compared with those from the experiments by other investigators which involve two specimens strengthened with NSM FRP rods added to one unstrengthened control specimen. The results, however, showed that the mid-span deflection responses of the predicted FE were in line with the corresponding data from the experiment for all the flexural loading stages. This was followed by the use of the validated FE models to analyze the effect of several properties of the FRP materials to provide more information than the limited experimental data available. It was discovered that the FE model developed is appropriate to be applied practically and economically with more focus on the parametric studies based on design to precisely model and analyze flexural negative moment strengthening for the RC members through the use of NSM FRP rods.","PeriodicalId":50625,"journal":{"name":"Computers and Concrete","volume":"61 1","pages":"347"},"PeriodicalIF":4.1,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74396456","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}
Pub Date : 2021-09-01DOI: 10.12989/CAC.2021.28.3.275
Ahmad Jabbar Hussain Alshimmeri, Denise‐Penelope N. Kontoni, A. Ghamari
In reinforced concrete (RC) frames, the applied seismic energy is dissipated through the ductile behavior of RC moment resisting frames. The main elements of the RC frames carry the gravity loads in addition to the seismic loads. Since the RC frames are sensitive to gravity loads, the ductility of the frames is reduced by increasing the gravity loads. Moreover, because of the low stiffness of the RC moment frames, huge member sizes of structural elements are required to control lateral drifts under lateral loading. In addition, the existing RC moment frame buildings with non-ductile characteristics pose a considerable hazard during earthquakes. To solve the mentioned problems, an innovative metallic damper with a shear link (metallic-passive energy damper) was developed in this paper. The proposed damper not only enjoys an easy fabrication and a good seismic performance but also can be easily replaced after a severe earthquake. Since the damper does not carry the gravity loads, replacing the damper does not affect the severability of the building during repairing. The main goal of this study is to confine the plastic deformation in the proposed damper. The numerical results indicated that the proposed damper improved the behavior of the RC frame in elastic and inelastic zones. It enhanced the shear capacity, shear stiffness, energy absorption, and ductility of the RC moment resisting frame. The results indicated that the proposed damper enhances the shear stiffness and the ultimate shear capacity from a minimum of 11% to a maximum of 24% and from a minimum of 11% to a maximum of 48%, respectively. Also, the proposed damper improved the yielding strength from a minimum of 53% to a maximum of 61%. Moreover, the dynamic analysis indicated that the damper improved the behavior of the system in the case of maximum lateral displacement and base shear. Based on the time-history dynamic analysis, dampers in the 5- and 10-story frames are more effective compared to the 15-story frame. This result confirms the suitable performance of the proposed damper. Herein the required equations and the recommendations for the design of the proposed metallic-shear damper have been presented.
{"title":"Improving the seismic performance of reinforced concrete frames using an innovative metallic-shear damper","authors":"Ahmad Jabbar Hussain Alshimmeri, Denise‐Penelope N. Kontoni, A. Ghamari","doi":"10.12989/CAC.2021.28.3.275","DOIUrl":"https://doi.org/10.12989/CAC.2021.28.3.275","url":null,"abstract":"In reinforced concrete (RC) frames, the applied seismic energy is dissipated through the ductile behavior of RC moment resisting frames. The main elements of the RC frames carry the gravity loads in addition to the seismic loads. Since the RC frames are sensitive to gravity loads, the ductility of the frames is reduced by increasing the gravity loads. Moreover, because of the low stiffness of the RC moment frames, huge member sizes of structural elements are required to control lateral drifts under lateral loading. In addition, the existing RC moment frame buildings with non-ductile characteristics pose a considerable hazard during earthquakes. To solve the mentioned problems, an innovative metallic damper with a shear link (metallic-passive energy damper) was developed in this paper. The proposed damper not only enjoys an easy fabrication and a good seismic performance but also can be easily replaced after a severe earthquake. Since the damper does not carry the gravity loads, replacing the damper does not affect the severability of the building during repairing. The main goal of this study is to confine the plastic deformation in the proposed damper. The numerical results indicated that the proposed damper improved the \u0000behavior of the RC frame in elastic and inelastic zones. It enhanced the shear capacity, shear stiffness, energy absorption, and ductility of the RC moment resisting frame. The results indicated that the proposed damper enhances the shear stiffness and the ultimate shear capacity from a minimum of 11% to a maximum of 24% and from a minimum of 11% to a maximum of 48%, respectively. Also, the proposed damper improved the yielding strength from a minimum of 53% to a maximum of 61%. Moreover, the dynamic analysis indicated that the damper improved the behavior of the system in the case of maximum lateral displacement and base shear. Based on the time-history dynamic analysis, dampers in the 5- and 10-story frames are more effective compared to the 15-story frame. This result confirms the suitable performance of the proposed damper. Herein the required equations and the recommendations for the design of the proposed metallic-shear damper have been presented.","PeriodicalId":50625,"journal":{"name":"Computers and Concrete","volume":"56 1","pages":"275"},"PeriodicalIF":4.1,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77629816","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}
Pub Date : 2021-09-01DOI: 10.12989/CAC.2021.28.3.243
A. Habibi, M. Izadpanah, Mohsen Ghasem Fam
Recently, designing irregular structures has been interested among civil engineers. The existing seismic codes like Iranian one do not present the separated response modification factor for regular and irregular structures. In this study, a procedure is presented to estimate the response modification factor of irregular Reinforced Concrete Moment Resisting Frames (RCMRFs). To do so, firstly, several irregular RCMRFs with various types of irregularity are designed based on the behavior factor of Iranian seismic code. Then, the inter-story drifts of these frames subjected to the proportional seismic ground motions are achieved and evaluated by the acceptance criteria. Secondly, the behavior factors of the aforementioned frames resulting from pushover analysis are acquired and the frames are redesigned based on these behavior factors. After that, the inter-story drifts of redesigned frames are again obtained and it is shown that these frames satisfy the admissible restrictions. In addition, two new relations are presented to acquire the behavior factor and the main period of irregular RCMRFs. Six new irregular RCMRFs are designed using the behavior factors achieved via the proposed relations. The behavior factors and the fundamental periods of these frames, which are computed from pushover and modal analyses respectively, are compared with those achieved via the presented relations. This comparison validates the accuracy of the suggested relations.
{"title":"An approximate method for determining the behavior factorof RCMRFs with vertical irregularity","authors":"A. Habibi, M. Izadpanah, Mohsen Ghasem Fam","doi":"10.12989/CAC.2021.28.3.243","DOIUrl":"https://doi.org/10.12989/CAC.2021.28.3.243","url":null,"abstract":"Recently, designing irregular structures has been interested among civil engineers. The existing seismic codes like Iranian one do not present the separated response modification factor for regular and irregular structures. In this study, a procedure is presented to estimate the response modification factor of irregular Reinforced Concrete Moment Resisting Frames (RCMRFs). To do so, firstly, several irregular RCMRFs with various types of irregularity are designed based on the behavior factor of Iranian seismic code. Then, the inter-story drifts of these frames subjected to the proportional seismic ground motions are achieved and evaluated by the acceptance criteria. Secondly, the behavior factors of the aforementioned frames resulting from pushover analysis are acquired and the frames are redesigned based on these behavior factors. After that, the inter-story drifts of redesigned frames are again obtained and it is shown that these frames satisfy the admissible restrictions. In addition, two new relations are presented to acquire the behavior factor and the main period of irregular RCMRFs. Six new irregular RCMRFs are designed using the behavior factors achieved via the proposed relations. The behavior factors and the fundamental periods of these frames, which are computed from pushover and modal analyses respectively, are compared with those achieved via the presented relations. This comparison validates the accuracy of the suggested relations.","PeriodicalId":50625,"journal":{"name":"Computers and Concrete","volume":"70 1","pages":"243"},"PeriodicalIF":4.1,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86191564","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}
Pub Date : 2021-09-01DOI: 10.12989/CAC.2021.28.3.289
Mohammad Saeed Amini, V. Sarfarazi, N. Babanouri
Discrete element and experimental approaches were utilized for investigating the effects of non-persistent joint sets on the failure behaviour of concrete under uniaxial compressive test. concrete specimens (100 mmx120 mmx50 mm dimension) were prepared. Tensile strength of concrete was 1 MPa. Two sets of specimens consisting three and five joints were prepared. These joint have two different parallel and intersecting configurations. In samples consisting both of the parallel and intersecting configurations with three joints, the length of larger joint was 6 cm and the lengths of two small joints was 3 cm. In samples consisting both of the parallel and intersecting configurations with five joints, The length of two larger joints were 3 cm and the lengths of three small joints was 2 cm. When the notch number was 3, the angle of larger joints were changed from 0o to 90o by increasing the 30o. When the notch number was 5, the angle of smaller joints were changed from 0o to 90o by increasing the 30o. In intersectiong joint configurations, two joint sets were perpendiqular to eachother. Totally, 16 different models were tested under compression test. Cuncurrent with experimental tests, numerical simulation (Particle flow code in two dimension) were performed on the models comprising non-persistent joint sets. joints configurations were similar to experimental one. the results revealed that the failure procedure was governed mostly by both of the joint configuration. The specimens' compressive strengths were associated with the failure mechanism and fracture pattern of the discontinuities. Furthermore it was shown that the discontinuities' compressive behaviour is caused by the number of the induced tensile cracks incremented by decreasing the joint length. Only some AE hits exist in the initial phase of loading, then AE hits grow rapidly prior to reaching the peak applied stress. Moreover, every stress drop was convoyed by numerous AE hits. Finally, the failure strength and pattern are similar in both approaches of the experimental tests and the numerical simulation.
{"title":"Influence of non-persistent joint sets on the failure behaviour of concrete under uniaxial compression test","authors":"Mohammad Saeed Amini, V. Sarfarazi, N. Babanouri","doi":"10.12989/CAC.2021.28.3.289","DOIUrl":"https://doi.org/10.12989/CAC.2021.28.3.289","url":null,"abstract":"Discrete element and experimental approaches were utilized for investigating the effects of non-persistent joint sets on the failure behaviour of concrete under uniaxial compressive test. concrete specimens (100 mmx120 mmx50 mm dimension) were prepared. Tensile strength of concrete was 1 MPa. Two sets of specimens consisting three and five joints were prepared. These joint have two different parallel and intersecting configurations. In samples consisting both of the parallel and intersecting configurations with three joints, the length of larger joint was 6 cm and the lengths of two small joints was 3 cm. In samples consisting both of the parallel and intersecting configurations with five joints, The length of two larger joints were 3 cm and the lengths of three small joints was 2 cm. When the notch number was 3, the angle of larger joints were changed from 0o to 90o by increasing the 30o. When the notch number was 5, the angle of smaller joints were changed from 0o to 90o by increasing the 30o. In intersectiong joint configurations, two joint sets were perpendiqular to eachother. Totally, 16 different models were tested under compression test. Cuncurrent with experimental tests, numerical simulation (Particle flow code in two dimension) were performed on the models comprising non-persistent joint sets. joints configurations were similar to experimental one. the results revealed that the failure procedure was governed mostly by both of the joint configuration. The specimens' compressive strengths were associated with the failure mechanism and fracture pattern of the discontinuities. Furthermore it was shown that the discontinuities' compressive behaviour is caused by the number of the induced tensile cracks incremented by decreasing the joint length. Only some AE hits exist in the initial phase of loading, then AE hits grow rapidly prior to reaching the peak applied stress. Moreover, every stress drop was convoyed by numerous AE hits. Finally, the failure strength and pattern are similar in both approaches of the experimental tests and the numerical simulation.","PeriodicalId":50625,"journal":{"name":"Computers and Concrete","volume":"38 1","pages":"289"},"PeriodicalIF":4.1,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75089236","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 large diameter reinforced concrete drain-pipe were applied in a underground drain-pipe jacking engineering. The inside and outside diameter of the drain-pipe are 3.5 m and 4.2 m respectively. The weight is 26000 kg, and jacking distance is 640 m. The nondestructive testing technology and three-edge bearing test were used to evaluate quality of the two large diameter concrete drain-pipe which selected randomly in engineering. The load-displacement curves and load-strain curves of drain-pipe were obtained, the global and local deformation laws of drain-pipe were analyzed through static test. The finite element model was established by ABAQUS, and the test results and simulation results were compared. The results of comparison show that the displacement of each measuring point increases with increasing load, and both of the two drain-pipe show well overall performance, and the well overall performance was shown in both of the two drain-pipe. The maximum displacement and strain were measured at the top of the drain-pipe, and the cracks are observed at the sidewall and bottom of drain-pipe. The load-displacement curves from simulation results is in well agree with the load-displacement curves from test results. It means that there is a good accuracy of the calculation results with the finite element model, which could be used as the basis for the corresponding research. Cracking load values under three-edge bearing test (the load value when the width of crack reaches 0.20 mm) of the two drain-pipe are 325 kN/m and 324 kN/m, respectively. And both drain-pipe meet the Chinese national standard, which the large diameter reinforced concrete drain-pipe could be used in actual engineering.
{"title":"Based on experiment and simulation to evaluate the qualityof large diameter concrete drain-pipe by jacking method","authors":"Yanmin Yang, Zhixin Zhang, Yongqing Li, Zesen Ge, Y. Xiong, Xiangkun Meng","doi":"10.12989/CAC.2021.28.3.321","DOIUrl":"https://doi.org/10.12989/CAC.2021.28.3.321","url":null,"abstract":"The large diameter reinforced concrete drain-pipe were applied in a underground drain-pipe jacking engineering. \u0000The inside and outside diameter of the drain-pipe are 3.5 m and 4.2 m respectively. The weight is 26000 kg, and jacking distance is 640 m. The nondestructive testing technology and three-edge bearing test were used to evaluate quality of the two large diameter concrete drain-pipe which selected randomly in engineering. The load-displacement curves and load-strain curves of drain-pipe were obtained, the global and local deformation laws of drain-pipe were analyzed through static test. The finite element model was established by ABAQUS, and the test results and simulation results were compared. The results of comparison show that the displacement of each measuring point increases with increasing load, and both of the two drain-pipe show well overall performance, and the well overall performance was shown in both of the two drain-pipe. The maximum displacement and strain were measured at the top of the drain-pipe, and the cracks are observed at the sidewall and bottom of drain-pipe. The load-displacement curves from simulation results is in well agree with the load-displacement curves from test results. It means that there is a good accuracy of the calculation results with the finite element model, which could be used as the basis for the corresponding research. Cracking load values under three-edge bearing test (the load value when the width of crack reaches 0.20 mm) of the two drain-pipe are 325 kN/m and 324 kN/m, respectively. And both drain-pipe meet the Chinese national standard, which the large diameter reinforced concrete drain-pipe could be used in actual engineering.","PeriodicalId":50625,"journal":{"name":"Computers and Concrete","volume":"54 1","pages":"321"},"PeriodicalIF":4.1,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87150615","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}
Pub Date : 2021-09-01DOI: 10.12989/CAC.2021.28.3.311
O. Ibraheem, Osama A. Mukhlif
The present study investigated experimentally and numerically the behavior of reinforced concrete plates subjected to pure torsion. The main parameters examined were: steel reinforcement ratio or spacing and plate width. A pure torsion test was carried out on nine reinforced concrete plate with different dimensions and reinforcement. A 3D numerical analysis by the finite element method and a torsion theories were adopted for all specimens tested. The finite element results overestimate the cracking torque, accurate of ultimate torque. Skew-bending theory calculate the cracking torque more accurate compared to FE and other theories. Moreover, ACI318-14 building code is unconservative for cracking torque, conservative of ultimate torque.
{"title":"Torsional behavior of reinforced concrete plates under pure torsion","authors":"O. Ibraheem, Osama A. Mukhlif","doi":"10.12989/CAC.2021.28.3.311","DOIUrl":"https://doi.org/10.12989/CAC.2021.28.3.311","url":null,"abstract":"The present study investigated experimentally and numerically the behavior of reinforced concrete plates subjected to pure torsion. The main parameters examined were: steel reinforcement ratio or spacing and plate width. A pure torsion test was carried out on nine reinforced concrete plate with different dimensions and reinforcement. A 3D numerical analysis by the finite element method and a torsion theories were adopted for all specimens tested. The finite element results overestimate the cracking torque, accurate of ultimate torque. Skew-bending theory calculate the cracking torque more accurate compared to FE and other theories. Moreover, ACI318-14 building code is unconservative for cracking torque, conservative of ultimate torque.","PeriodicalId":50625,"journal":{"name":"Computers and Concrete","volume":"89 4 1","pages":"311"},"PeriodicalIF":4.1,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83636410","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}
Pub Date : 2021-09-01DOI: 10.12989/CAC.2021.28.3.233
Jun Liu, Houli Wang, Hongmei Yin
Based on differential quadrature method (DQM), a nonlinear vibrational analysis of hybrid multi-scale cylindrical panels has been performed in this article. The mechanical properties of hybrid composites have been formulated within the framework of three-dimensional Mori-Tanaka model taking into consideration the effects of unidirectional oriented fibers and randomly dispersed carbon nanotubes (CNTs). The governing equations for cylindrical panels have been established with respect to thin shell assumptions taking into account geometrical non-linearity. Next, DQM has been used to solve the governing equations for establishing the frequency-deflection curves of the cylindrical panel. It will be exhibited that frequency-deflection curves change by the varying of CNT weight fractions, fiber orientations, fiberglass volume, panel radius and dimension of CNTs.
{"title":"Nonlinear vibration behavior of hybrid multi-scale cylindrical panels via semi numerical method","authors":"Jun Liu, Houli Wang, Hongmei Yin","doi":"10.12989/CAC.2021.28.3.233","DOIUrl":"https://doi.org/10.12989/CAC.2021.28.3.233","url":null,"abstract":"Based on differential quadrature method (DQM), a nonlinear vibrational analysis of hybrid multi-scale cylindrical \u0000panels has been performed in this article. The mechanical properties of hybrid composites have been formulated within the framework of three-dimensional Mori-Tanaka model taking into consideration the effects of unidirectional oriented fibers and randomly dispersed carbon nanotubes (CNTs). The governing equations for cylindrical panels have been established with respect to thin shell assumptions taking into account geometrical non-linearity. Next, DQM has been used to solve the governing equations for establishing the frequency-deflection curves of the cylindrical panel. It will be exhibited that frequency-deflection curves change by the varying of CNT weight fractions, fiber orientations, fiberglass volume, panel radius and dimension of CNTs.","PeriodicalId":50625,"journal":{"name":"Computers and Concrete","volume":"106 1","pages":"233"},"PeriodicalIF":4.1,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77451960","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}
Pub Date : 2021-09-01DOI: 10.12989/CAC.2021.28.3.259
J. Rajabi, M. Mohammadimehr
In this study, the forced vibration analysis of a micro sandwich plate with an isotropic/orthotropic cores and polymeric nanocomposite face sheets is taken into account based on first order shear deformation theory (FSDT). The core of this plate is considered as five isotropic Devineycell materials (H30, H45, H60, H100 and H200) and an orthotropic material, while facesheets layers are as polymeric matrix reinforced by carbon nanotubes under temperature-dependent and hydro material properties on the elastic foundations. The governing equations of motion are derived using the Hamilton's principle and then solved by analytical method. Also, the effects of different parameters such as size dependent, side ratio, volume fraction, various material properties of cores and facesheets and temperature and humidity changes on the dimensionless frequency are investigated. It is shown from the results that the dimensionless frequency for CT is lower than that of for MSGT. Also, it is presented that the least amplitude oscillation is related to the modified strain gradient theory due to higher stiffen. It is illustrated that the dimensionless frequency for Devineycell H200 is highest and lowest for H30. The results of this research can be used in aircraft, automotive, shipbuilding industries and biomedicine.
{"title":"Forced vibration analysis of a micro sandwich plate with an isotropic/orthotropic cores and polymeric nanocomposite face sheets","authors":"J. Rajabi, M. Mohammadimehr","doi":"10.12989/CAC.2021.28.3.259","DOIUrl":"https://doi.org/10.12989/CAC.2021.28.3.259","url":null,"abstract":"In this study, the forced vibration analysis of a micro sandwich plate with an isotropic/orthotropic cores and polymeric nanocomposite face sheets is taken into account based on first order shear deformation theory (FSDT). The core of this plate is considered as five isotropic Devineycell materials (H30, H45, H60, H100 and H200) and an orthotropic material, while facesheets layers are as polymeric matrix reinforced by carbon nanotubes under temperature-dependent and hydro material properties on the elastic foundations. The governing equations of motion are derived using the Hamilton's principle and then solved by analytical method. Also, the effects of different parameters such as size dependent, side ratio, volume fraction, various material properties of cores and facesheets and temperature and humidity changes on the dimensionless frequency are investigated. It is shown from the results that the dimensionless frequency for CT is lower than that of for MSGT. Also, it is presented that the least amplitude oscillation is related to the modified strain gradient theory due to higher stiffen. It is illustrated that the dimensionless frequency for Devineycell H200 is highest and lowest for H30. The results of this research can be used in aircraft, automotive, shipbuilding industries and biomedicine.","PeriodicalId":50625,"journal":{"name":"Computers and Concrete","volume":"44 1","pages":"259"},"PeriodicalIF":4.1,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73469712","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}
Pub Date : 2021-08-01DOI: 10.12989/CAC.2021.28.2.209
Erdal Öner
This study has been performed to investigate the receding contact problem of a homogeneous orthotropic coating that is not bonded to a homogeneous isotropic substrate without any interfacial defects. The isotropic substrate is supported on a Winkler foundation. The problem is solved assuming that the contact between the rigid punch and orthotropic coating, and that between the orthotropic coating and isotropic substrate, are frictionless. Additionally, the effect of the body forces is neglected, and only compressive normal tractions can be transmitted through the interfaces. The contact analysis of the orthotropic coating, which is subjected to a contact load using a rigid cylindrical punch, is performed under plane strain conditions. The governing equations are analytically found using the theory of elasticity and Fourier integral transformation techniques. Subsequently, the governing equations are reduced to a system of two singular equations, wherein the unknowns are the contact stresses and contact widths. To numerically solve the resulting singular integral equations, Gauss-Chebyshev integration formulas are employed. It is analyzed the influence of the following parameters on the contact stresses and contact widths: orthotropicmaterial properties, punch radius, load ratio, Winkler foundation stiffness.
{"title":"Frictionless contact mechanics of an orthotropic coating/isotropic substrate system","authors":"Erdal Öner","doi":"10.12989/CAC.2021.28.2.209","DOIUrl":"https://doi.org/10.12989/CAC.2021.28.2.209","url":null,"abstract":"This study has been performed to investigate the receding contact problem of a homogeneous orthotropic coating that is not bonded to a homogeneous isotropic substrate without any interfacial defects. The isotropic substrate is supported on a Winkler foundation. The problem is solved assuming that the contact between the rigid punch and orthotropic coating, and that between the orthotropic coating and isotropic substrate, are frictionless. Additionally, the effect of the body forces is neglected, and only compressive normal tractions can be transmitted through the interfaces. The contact analysis of the orthotropic coating, which is subjected to a contact load using a rigid cylindrical punch, is performed under plane strain conditions. The governing equations are analytically found using the theory of elasticity and Fourier integral transformation techniques. Subsequently, the governing equations are reduced to a system of two singular equations, wherein the unknowns are the contact stresses and contact widths. To numerically solve the resulting singular integral equations, Gauss-Chebyshev integration formulas are employed. It is analyzed the influence of the following parameters on the contact stresses and contact widths: orthotropicmaterial properties, punch radius, load ratio, Winkler foundation stiffness.","PeriodicalId":50625,"journal":{"name":"Computers and Concrete","volume":"15 1","pages":"209"},"PeriodicalIF":4.1,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75878311","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}
Pub Date : 2021-08-01DOI: 10.12989/CAC.2021.28.2.137
M. Ebadi-Jamkhaneh, Amir Homaioon-Ebrahimi, Denise‐Penelope N. Kontoni
Concrete spalling is considered as one of the most common weaknesses phenomena in concrete members. In this article, reinforced concrete (RC) column and beam members are subject to a variety of loads under damaged and strengthened conditions using carbon and glass fiber reinforced polymer (FRP) wraps. The main parameters in this study include the number of the FRP layers, the materials of the strengthening FRP layers, and the loading types. The imposed loads include pure bending moment, shear, and pure torsional moment, to enable studying the structural elements's behaviors under such states. The numerical finite element (FE) model was verified using experimental results, and 10 different case numerical FE models were analyzed. The analysis results demonstrated that using an FRP layer increases the shearing and torsional capacities. Adding another FRP layer does not significantly affect the models' behavioral specifications. In both RC beam and column, this strengthening method did not affect the torsional capacity, while managed to prevent sudden capacity loss and enhance ductility.
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