This study carries out an experimental and numerical work in order to investigate the air flow and temperature fields inside a coach bus cabin. In addition to a real-world experiment, an existing bus heating system has been investigated computationally using a three-dimensional model consisting of one seating row with periodical and symmetrical boundary conditions (BCs) as required. The seats, without including passengers as has been the case in the experiments, are created with adiabatic BCs. The developed computational fluid dynamics (CFD) model is used in a transient analysis of heating by employing the “Boussinesq Approximation” for buoyancy-induced effects and incorporating the experimentally obtained BCs into the system. The model validation is performed by comparing model results against experimentally obtained ones for three regions, corresponding to head, knee, and foot level of passengers. The difference between the measured and the calculated temperatures is found to be less than around 3°C for the head and foot level, while it is 5°C for the knee level of the passenger for the transient heating simulation.
{"title":"EXPERIMENTAL AND NUMERICAL INVESTIGATIONS OF HEATING IN A BUS CABIN UNDER TRANSIENT STATE CONDITIONS","authors":"Özgür Ekici, Gökhan Güney","doi":"10.2495/CMEM170061","DOIUrl":"https://doi.org/10.2495/CMEM170061","url":null,"abstract":"This study carries out an experimental and numerical work in order to investigate the air flow and temperature fields inside a coach bus cabin. In addition to a real-world experiment, an existing bus heating system has been investigated computationally using a three-dimensional model consisting of one seating row with periodical and symmetrical boundary conditions (BCs) as required. The seats, without including passengers as has been the case in the experiments, are created with adiabatic BCs. The developed computational fluid dynamics (CFD) model is used in a transient analysis of heating by employing the “Boussinesq Approximation” for buoyancy-induced effects and incorporating the experimentally obtained BCs into the system. The model validation is performed by comparing model results against experimentally obtained ones for three regions, corresponding to head, knee, and foot level of passengers. The difference between the measured and the calculated temperatures is found to be less than around 3°C for the head and foot level, while it is 5°C for the knee level of the passenger for the transient heating simulation.","PeriodicalId":23647,"journal":{"name":"WIT transactions on engineering sciences","volume":"67 1","pages":"49-59"},"PeriodicalIF":0.0,"publicationDate":"2017-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81158060","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}
{"title":"PERFORMANCE EVALUATION OF A TRADITIONAL WOODEN SHIP BY PRESERVED SKILL TECHNIQUES","authors":"Y. Ohbuchi, H. Sakamoto, M. Shimizu","doi":"10.2495/CMEM170091","DOIUrl":"https://doi.org/10.2495/CMEM170091","url":null,"abstract":"","PeriodicalId":23647,"journal":{"name":"WIT transactions on engineering sciences","volume":"138 1","pages":"83-94"},"PeriodicalIF":0.0,"publicationDate":"2017-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86519832","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}
A. Błachowski, A. K. Jasek, K. Komędera, A. Pierzga, K. Ruebenbauer, J. Żukrowski
This contribution attempts to be a review concerned with the microscopic characterization of complex materials by using transmission Mössbauer spectroscopy – mainly 14.4-keV resonant transition in Fe. An attention is focused on the novel superconductors, i.e. iron-based superconductors, the latter being extensively investigated in our Mössbauer laboratory primarily versus sample temperature. Iron-based superconductors make four major families based on the corrugated nearly twodimensional sheets of either strongly bound iron-pnictogen or iron-chalcogen atoms. Usually, superconductivity is induced by doping or applying pressure to the parent compound except the simplest compounds of the ‘11’ family. One can dope any kind of atom within the compound in isovalent, hole-doping or electron-doping fashion. Parent compounds exhibit itinerant magnetic order of the 3d (iron) character. It appears as spin density wave (SDW) of the antiferromagnetic type incommensurate with the respective lattice period and of the complex shape. For majority of cases it is longitudinal SDW propagating along the a-axis of the orthorhombic unit cell being created at the magnetic order from the tetragonal cell – due to the magneto-elastic forces. On the other hand, the 3d magnetism and orthorhombic distortion are gone for superconductors as shown by Mössbauer spectra obtained versus temperature, and by spectra obtained in the strong external magnetic field at low temperatures – stronger than the first critical field for these second kind superconductors. However, superconductivity is intimately related to these layered structures with the electronic charge modulation leading to the charge density wave (CDW) on iron nuclei – observed as variation of the isomer shift. What is more, one observes closely related modulation of the electric field gradient on iron nuclei called electric field gradient wave (EFGW). The shape of these modulations changes rapidly at the superconducting gap opening and relaxes back once the bosonic system of Cooper pairs is fairly well separated from the rest of the electronic system. It was found that localized 4f magnetic moments order within superconducting phase in a similar fashion as in the normal phase.
{"title":"MÖSSBAUER STUDIES OF IRON-BASED SUPERCONDUCTORS","authors":"A. Błachowski, A. K. Jasek, K. Komędera, A. Pierzga, K. Ruebenbauer, J. Żukrowski","doi":"10.2495/MC170151","DOIUrl":"https://doi.org/10.2495/MC170151","url":null,"abstract":"This contribution attempts to be a review concerned with the microscopic characterization of complex materials by using transmission Mössbauer spectroscopy – mainly 14.4-keV resonant transition in Fe. An attention is focused on the novel superconductors, i.e. iron-based superconductors, the latter being extensively investigated in our Mössbauer laboratory primarily versus sample temperature. Iron-based superconductors make four major families based on the corrugated nearly twodimensional sheets of either strongly bound iron-pnictogen or iron-chalcogen atoms. Usually, superconductivity is induced by doping or applying pressure to the parent compound except the simplest compounds of the ‘11’ family. One can dope any kind of atom within the compound in isovalent, hole-doping or electron-doping fashion. Parent compounds exhibit itinerant magnetic order of the 3d (iron) character. It appears as spin density wave (SDW) of the antiferromagnetic type incommensurate with the respective lattice period and of the complex shape. For majority of cases it is longitudinal SDW propagating along the a-axis of the orthorhombic unit cell being created at the magnetic order from the tetragonal cell – due to the magneto-elastic forces. On the other hand, the 3d magnetism and orthorhombic distortion are gone for superconductors as shown by Mössbauer spectra obtained versus temperature, and by spectra obtained in the strong external magnetic field at low temperatures – stronger than the first critical field for these second kind superconductors. However, superconductivity is intimately related to these layered structures with the electronic charge modulation leading to the charge density wave (CDW) on iron nuclei – observed as variation of the isomer shift. What is more, one observes closely related modulation of the electric field gradient on iron nuclei called electric field gradient wave (EFGW). The shape of these modulations changes rapidly at the superconducting gap opening and relaxes back once the bosonic system of Cooper pairs is fairly well separated from the rest of the electronic system. It was found that localized 4f magnetic moments order within superconducting phase in a similar fashion as in the normal phase.","PeriodicalId":23647,"journal":{"name":"WIT transactions on engineering sciences","volume":"136 1","pages":"151-160"},"PeriodicalIF":0.0,"publicationDate":"2017-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80059974","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}
Impact by foreign objects is a concern for most composite structures, requiring attention in damage threat assessment. The purpose is to identify impact damage severity and detectability for design and maintenance. Barely visible impact damage (BVID) requires special treatment due to the difficulties in detecting it by any visual inspection method. BVID can reduce the load-carrying capability of a composite structure and, therefore, it can cause severe damage. The low-velocity impact causing BVID in a composite panel was studied via a numerical method using finite elements (FEs) with the explicit dynamic integration method. A ply-by-ply three-dimensional model with cohesive zone behavior of interaction was created, enabling a detailed study of material degradation through composite thickness. Two cases with double impact and with no impact were analyzed. Impacts directed near the hole’s edge caused delamination and ply degradation. Subsequently applied shear loading shows the impact influence on the strength of the panel. The numerical results confirm a decrease in the strength of the composite panel after impact, as expected, but differences in displacement behavior were also observed. According to the FE solution, buckling appears in regions of impact before rupture, while test results reported rapid failures in the compression zone and tension zone, independently, in two stages. On the other hand, the FE results of the non-impacted panel show two independent failures, as observed experimentally. As a result, the unrealistic buckling is attributed to a decrease in element stiffness during impact. In conclusion, the final strength of the impacted panel was predicted by the FE solution sufficiently. The BVID modelling approach presented in this study is useful in the case of small-scale models such as a flat panel. The research has received funding from the European Union’s Seventh Framework Programme for Research, Technological Development and Demonstration within CANAL (CreAting NonconventionAl Laminates) project under grant agreement number 605583.
{"title":"NUMERICAL EVALUATION OF BARELY VISIBLE IMPACT DAMAGE IN A CARBON FIBRE-REINFORCED COMPOSITE PANEL WITH SHEAR LOADING","authors":"J. Šedek, P. Bělský","doi":"10.2495/MC170081","DOIUrl":"https://doi.org/10.2495/MC170081","url":null,"abstract":"Impact by foreign objects is a concern for most composite structures, requiring attention in damage threat assessment. The purpose is to identify impact damage severity and detectability for design and maintenance. Barely visible impact damage (BVID) requires special treatment due to the difficulties in detecting it by any visual inspection method. BVID can reduce the load-carrying capability of a composite structure and, therefore, it can cause severe damage. The low-velocity impact causing BVID in a composite panel was studied via a numerical method using finite elements (FEs) with the explicit dynamic integration method. A ply-by-ply three-dimensional model with cohesive zone behavior of interaction was created, enabling a detailed study of material degradation through composite thickness. Two cases with double impact and with no impact were analyzed. Impacts directed near the hole’s edge caused delamination and ply degradation. Subsequently applied shear loading shows the impact influence on the strength of the panel. The numerical results confirm a decrease in the strength of the composite panel after impact, as expected, but differences in displacement behavior were also observed. According to the FE solution, buckling appears in regions of impact before rupture, while test results reported rapid failures in the compression zone and tension zone, independently, in two stages. On the other hand, the FE results of the non-impacted panel show two independent failures, as observed experimentally. As a result, the unrealistic buckling is attributed to a decrease in element stiffness during impact. In conclusion, the final strength of the impacted panel was predicted by the FE solution sufficiently. The BVID modelling approach presented in this study is useful in the case of small-scale models such as a flat panel. The research has received funding from the European Union’s Seventh Framework Programme for Research, Technological Development and Demonstration within CANAL (CreAting NonconventionAl Laminates) project under grant agreement number 605583.","PeriodicalId":23647,"journal":{"name":"WIT transactions on engineering sciences","volume":"1 1","pages":"73-85"},"PeriodicalIF":0.0,"publicationDate":"2017-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88084669","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 study, we focused on the dynamics of the continuously changing microstructure at an elevated temperature upon tempering of stainless steel. We used a Scanning Electron Microscope (SEM) with an Electron Backscatter Diffraction (EBSD) setup in combination with a High Temperature specimen stage to perform in-situ orientation imaging microscopy experiments. This experimental setup allowed us to observe in-situ the microstructural changes like grain growth, grain-boundary movement and modification in crystal orientations. By subsequent imaging of the outer surface area, the evolution of the microstructure can be examined leading to a better understanding of the dynamics of the tempering process of stainless steel. In particular, we discussed the results obtained of the microstructural changes at a fixed temperature of 500°C. A loss of the EBSD signal started at the triple junctions and at high angle grain boundaries over time and is attributed to oxidation. We concluded that preferred oxidation occurs during treatment and that dynamic in situ observations are possible.
{"title":"DYNAMICS OF TEMPERING PROCESSES IN STAINLESS STEEL","authors":"L. D. Jeer, V. Ocelík, J. Hosson","doi":"10.2495/MC170191","DOIUrl":"https://doi.org/10.2495/MC170191","url":null,"abstract":"In this study, we focused on the dynamics of the continuously changing microstructure at an elevated temperature upon tempering of stainless steel. We used a Scanning Electron Microscope (SEM) with an Electron Backscatter Diffraction (EBSD) setup in combination with a High Temperature specimen stage to perform in-situ orientation imaging microscopy experiments. This experimental setup allowed us to observe in-situ the microstructural changes like grain growth, grain-boundary movement and modification in crystal orientations. By subsequent imaging of the outer surface area, the evolution of the microstructure can be examined leading to a better understanding of the dynamics of the tempering process of stainless steel. In particular, we discussed the results obtained of the microstructural changes at a fixed temperature of 500°C. A loss of the EBSD signal started at the triple junctions and at high angle grain boundaries over time and is attributed to oxidation. We concluded that preferred oxidation occurs during treatment and that dynamic in situ observations are possible.","PeriodicalId":23647,"journal":{"name":"WIT transactions on engineering sciences","volume":"1 1","pages":"187-193"},"PeriodicalIF":0.0,"publicationDate":"2017-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75305511","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}
M. Fukumoto, Daiki Suzuki, Natsuki Maeda, M. Jinbo
Transition phenomenon in the flattening behavior of the thermally sprayed metallic particles has been recognized in our series of experimental works. Based on the results, a hypothesis has been proposed, namely, ultra-rapid cooled chill structure, preferentially formed at the bottom part of the splat, plays an essential role for the generation of the disk splat. Universality of this hypothesis beyond material difference was verified experimentally in our recent study, by using several kinds of ceramic materials with different thermal properties. To perform this, Al 2 O 3 , Y 2 O 3 and YSZ powder materials were plasma sprayed onto AISI304 stainless steel substrate, and a fractional change of the disk splat with a substrate temperature increase was investigated, followed by a precise observation of the cross-section microstructure of the splats. The results obtained showed that unique amorphous and chill structures were observed in Al 2 O 3 and Y 2 O 3 splat at the bottom, respectively, indicating that similar disk formation mechanism in metallic material may act in these materials. On the other hand, only normal columnar structure was recognized in YSZ splat. It was indicated that a rapid increase in viscosity may act on this material. Consequently, our hypothesis was verified partially, beyond the materials difference.
{"title":"THE SPLAT FORMATION ISSUE IN THERMAL SPRAY PROCESSES","authors":"M. Fukumoto, Daiki Suzuki, Natsuki Maeda, M. Jinbo","doi":"10.2495/MC170181","DOIUrl":"https://doi.org/10.2495/MC170181","url":null,"abstract":"Transition phenomenon in the flattening behavior of the thermally sprayed metallic particles has been recognized in our series of experimental works. Based on the results, a hypothesis has been proposed, namely, ultra-rapid cooled chill structure, preferentially formed at the bottom part of the splat, plays an essential role for the generation of the disk splat. Universality of this hypothesis beyond material difference was verified experimentally in our recent study, by using several kinds of ceramic materials with different thermal properties. To perform this, Al 2 O 3 , Y 2 O 3 and YSZ powder materials were plasma sprayed onto AISI304 stainless steel substrate, and a fractional change of the disk splat with a substrate temperature increase was investigated, followed by a precise observation of the cross-section microstructure of the splats. The results obtained showed that unique amorphous and chill structures were observed in Al 2 O 3 and Y 2 O 3 splat at the bottom, respectively, indicating that similar disk formation mechanism in metallic material may act in these materials. On the other hand, only normal columnar structure was recognized in YSZ splat. It was indicated that a rapid increase in viscosity may act on this material. Consequently, our hypothesis was verified partially, beyond the materials difference.","PeriodicalId":23647,"journal":{"name":"WIT transactions on engineering sciences","volume":"1 1","pages":"181-185"},"PeriodicalIF":0.0,"publicationDate":"2017-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82865732","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 effects of microstructure transformation during forming processes viz. Mechanical (contact process via tool and die), laser (contactless process via CO2 laser defocused beam) and a combined process consisting of laser forming followed by mechanical forming was analysed before and after each process. Plastic flow during the deformation is strongly influenced by anisotropy and the work hardening rate, which is due to the limited number of slip planes in a hexagonal close-packed material. Commercially pure titanium can exhibit dominant twinning systems during deformation when either tensile or compression is introduced. Electron backscatter diffraction (EBSD) results show multiple dominate pyramidal slip behaviours due to the lattice rotation when comparing the before and after deformation processes. The Schmid factor and twinning parent/daughter ratios for each individual grain after each forming process were also evaluated. Our findings show twin nucleation and twin growth also contribute a major role when observing the nature of the microstructure for each process. contribute a major role when observing the nature of the microstructure for each process.
{"title":"Microstructure transformation of Αlpha-titanium after mechanical and laser forming","authors":"H. Fidder, V. Ocelík, J. Hosson","doi":"10.2495/MC170221","DOIUrl":"https://doi.org/10.2495/MC170221","url":null,"abstract":"The effects of microstructure transformation during forming processes viz. Mechanical (contact process via tool and die), laser (contactless process via CO2 laser defocused beam) and a combined process consisting of laser forming followed by mechanical forming was analysed before and after each process. Plastic flow during the deformation is strongly influenced by anisotropy and the work hardening rate, which is due to the limited number of slip planes in a hexagonal close-packed material. Commercially pure titanium can exhibit dominant twinning systems during deformation when either tensile or compression is introduced. Electron backscatter diffraction (EBSD) results show multiple dominate pyramidal slip behaviours due to the lattice rotation when comparing the before and after deformation processes. The Schmid factor and twinning parent/daughter ratios for each individual grain after each forming process were also evaluated. Our findings show twin nucleation and twin growth also contribute a major role when observing the nature of the microstructure for each process. contribute a major role when observing the nature of the microstructure for each process.","PeriodicalId":23647,"journal":{"name":"WIT transactions on engineering sciences","volume":"69 1","pages":"215-222"},"PeriodicalIF":0.0,"publicationDate":"2017-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90882879","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}
Kazuto Tanaka, Kaito Karasuno, Noguchi Ryuichi, T. Katayama
The press and injection hybrid molding system, which is a novel molding technology with the combination of press molding and injection molding, is expected for the production of FRTP (Fiber Reinforced Thermoplastics) with complicated shapes and high levels of stiffness and strength. Press and injection hybrid molded structures consist of an outer shell laminate of continuous fiber and injected short or long fiber reinforced thermoplastics which form the rib structure. The higher mold temperature was reported to increase the strength of the interface between the outer shell laminate and injected material. On the other hand, the penetration of continuous fibers of the outer shell laminate into the rib structure decreases the mechanical properties of the outer shell laminate. While the effects of mold temperature on the mechanical properties of hybrid molded composites were clarified, the effects of press pressure have not been clarified yet. In this study, the effects of the press pressure on the mechanical properties of the outer shell laminate and interfacial strength between the outer shell laminate and injected material were evaluated. As the lower press pressure decreases, the penetrated height of continuous fiber into the rib structure, higher in-plane tensile strength and lower interfacial strength, are obtained.
{"title":"EFFECTS OF PRESS PRESSURE ON THE MECHANICAL PROPERTIES OF RIB ROOT FOR GLASS FIBER REINFORCED POLYPROPYLENE COMPOSITES, MOLDED BY PRESS AND INJECTION HYBRID MOLDING","authors":"Kazuto Tanaka, Kaito Karasuno, Noguchi Ryuichi, T. Katayama","doi":"10.2495/MC170331","DOIUrl":"https://doi.org/10.2495/MC170331","url":null,"abstract":"The press and injection hybrid molding system, which is a novel molding technology with the combination of press molding and injection molding, is expected for the production of FRTP (Fiber Reinforced Thermoplastics) with complicated shapes and high levels of stiffness and strength. Press and injection hybrid molded structures consist of an outer shell laminate of continuous fiber and injected short or long fiber reinforced thermoplastics which form the rib structure. The higher mold temperature was reported to increase the strength of the interface between the outer shell laminate and injected material. On the other hand, the penetration of continuous fibers of the outer shell laminate into the rib structure decreases the mechanical properties of the outer shell laminate. While the effects of mold temperature on the mechanical properties of hybrid molded composites were clarified, the effects of press pressure have not been clarified yet. In this study, the effects of the press pressure on the mechanical properties of the outer shell laminate and interfacial strength between the outer shell laminate and injected material were evaluated. As the lower press pressure decreases, the penetrated height of continuous fiber into the rib structure, higher in-plane tensile strength and lower interfacial strength, are obtained.","PeriodicalId":23647,"journal":{"name":"WIT transactions on engineering sciences","volume":"12 1","pages":"317-326"},"PeriodicalIF":0.0,"publicationDate":"2017-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81243416","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}
Kazuto Tanaka, Shun Akamatsu, J. Nakatsuka, T. Katayama
{"title":"FEM ANALYSIS OF TEMPERATURE DISTRIBUTION OF A FLAT PLATE MOLD WITH HOLLOWS, HEATED BY DIRECT RESISTANCE HEATING","authors":"Kazuto Tanaka, Shun Akamatsu, J. Nakatsuka, T. Katayama","doi":"10.2495/MC170351","DOIUrl":"https://doi.org/10.2495/MC170351","url":null,"abstract":"","PeriodicalId":23647,"journal":{"name":"WIT transactions on engineering sciences","volume":"19 1","pages":"337-344"},"PeriodicalIF":0.0,"publicationDate":"2017-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79561021","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 paper presents a conceptual framework to locate the damages and diagnose the type of damage. The proposed framework is based on flexibility difference method. The considered structural damages in the framework are categorized as the significant loss of section due to corrosion, cracks due to fatigue or fracture and interaction effect of corrosion-fatigue. The framework consists of a location specified damage index, which is determined by in-situ measurements of vibration modal parameters. The degree of damage is determined proportions to the magnitude of the damage index. The framework provides guidelines to locate the damage or deteriorated region for detailed investigation. A finite element simulation based approach is newly proposed to diagnose the type of damage. Initially paper presents the theoretical derivation of damage index based on flexibility difference. Then the methodology the locate the damages are discussed in detail. Finally, a new approach is proposed to diagnose the type of damage. The scope of this framework is limited to the steel/metal truss bridges. The proposed methodology is comprehensively discussed and is illustrated in a flowchart. The damages or deteriorations due to fully section loss of members, which are difficult to access for visual inspections, can be accurately located by the proposed conceptual framework.
{"title":"MODAL FLEXIBILITY-BASED DAMAGE DETECTION OF TRUSS BRIDGES: A CONCEPTUAL FRAMEWORK","authors":"S. Siriwardane","doi":"10.2495/MC170131","DOIUrl":"https://doi.org/10.2495/MC170131","url":null,"abstract":"This paper presents a conceptual framework to locate the damages and diagnose the type of damage. The proposed framework is based on flexibility difference method. The considered structural damages in the framework are categorized as the significant loss of section due to corrosion, cracks due to fatigue or fracture and interaction effect of corrosion-fatigue. The framework consists of a location specified damage index, which is determined by in-situ measurements of vibration modal parameters. The degree of damage is determined proportions to the magnitude of the damage index. The framework provides guidelines to locate the damage or deteriorated region for detailed investigation. A finite element simulation based approach is newly proposed to diagnose the type of damage. Initially paper presents the theoretical derivation of damage index based on flexibility difference. Then the methodology the locate the damages are discussed in detail. Finally, a new approach is proposed to diagnose the type of damage. The scope of this framework is limited to the steel/metal truss bridges. The proposed methodology is comprehensively discussed and is illustrated in a flowchart. The damages or deteriorations due to fully section loss of members, which are difficult to access for visual inspections, can be accurately located by the proposed conceptual framework.","PeriodicalId":23647,"journal":{"name":"WIT transactions on engineering sciences","volume":"5 1","pages":"131-137"},"PeriodicalIF":0.0,"publicationDate":"2017-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74170587","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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