Leading edge manufacturing industries, such as automotive or aerospace, need to develop multi-material solutions in order to optimize their products for a variety of attributes and to deliver the most costeffective solutions. Companies demand efficient and novel topology optimization strategies, where not only the topology is optimized, but also the distribution of several materials within it. Additive Manufacturing is one of the best known procedures to build up such multi-material solutions, but also more traditional procedures such as welding or thermoforming can be in play. This paper aims to describe a preliminary approach to face multi-material topology optimization considering not only mass or volume, but also material costs. The material selection is based on a given pool, either a database or a relevant set provided by the requesting company. Coupled material-manufacturing information needs to be gathered for the material selection approach, which will take into account the most relevant properties (e.g. density, Young’s modulus, but also cost and manufacturability) and will allow the use of them as an input in the optimization framework. Estimations of the different costs will be introduced into the multi-material topology optimization algorithm through the definition of a suitable cost model. This model will allow us to quantify the total cost as an attribute of the design so that it can be used either as an optimization objective function or constraint. The framework proposed in this research is based on two codes available in literature: a 2D multi-material topology optimization code, in which material interpolation is proposed within the topology optimization without including any extra design variables, and a 3D topology optimization code. The approach proposed here is able to do 3D multi-material topology optimization and searches the performance – cost Pareto front (e.g. normalized compliance – material cost), such that the final decision can be made by the company. A generic case consisting of a bike frame is presented to show these advances in the optimization framework.
{"title":"A PRELIMINARY APPROACH TO MULTI-MATERIAL TOPOLOGY OPTIMIZATION CONSIDERING COST ESTIMATION","authors":"Carlos López, S. Burggraeve, J. Stroobants","doi":"10.2495/HPSM180131","DOIUrl":"https://doi.org/10.2495/HPSM180131","url":null,"abstract":"Leading edge manufacturing industries, such as automotive or aerospace, need to develop multi-material solutions in order to optimize their products for a variety of attributes and to deliver the most costeffective solutions. Companies demand efficient and novel topology optimization strategies, where not only the topology is optimized, but also the distribution of several materials within it. Additive Manufacturing is one of the best known procedures to build up such multi-material solutions, but also more traditional procedures such as welding or thermoforming can be in play. This paper aims to describe a preliminary approach to face multi-material topology optimization considering not only mass or volume, but also material costs. The material selection is based on a given pool, either a database or a relevant set provided by the requesting company. Coupled material-manufacturing information needs to be gathered for the material selection approach, which will take into account the most relevant properties (e.g. density, Young’s modulus, but also cost and manufacturability) and will allow the use of them as an input in the optimization framework. Estimations of the different costs will be introduced into the multi-material topology optimization algorithm through the definition of a suitable cost model. This model will allow us to quantify the total cost as an attribute of the design so that it can be used either as an optimization objective function or constraint. The framework proposed in this research is based on two codes available in literature: a 2D multi-material topology optimization code, in which material interpolation is proposed within the topology optimization without including any extra design variables, and a 3D topology optimization code. The approach proposed here is able to do 3D multi-material topology optimization and searches the performance – cost Pareto front (e.g. normalized compliance – material cost), such that the final decision can be made by the company. A generic case consisting of a bike frame is presented to show these advances in the optimization framework.","PeriodicalId":340058,"journal":{"name":"High Performance and Optimum Design of Structures and Materials III","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124846922","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 mechanical and physical properties of potassium titanate whisker (PTW) reinforced epoxy nanocomposites have been studied to examine the contribution of PTW loading and surface modification effects on these properties. Tensile tests and micro-hardness measurements have been used to study the mechanical performance of epoxy-based nanocomposites reinforced with 1 wt% to 5 wt% of PTW. We found that the mechanical properties and micro-hardness of PTW-reinforced epoxy nanocomposites become higher than those of neat epoxy resin. Furthermore, the experimental results showed that the nanocomposites reinforced with silane-treated PTW have higher tensile strength and Young’s modulus. The micro-hardness of the treated PTW nanocomposites also had higher values as compared with that of untreated PTW nanocomposites. These results indicate that the mechanical performances of the PTW/epoxy nanocomposites were controlled by the silane surface treatment. Scanning electron microscopy studies indicated that the fracture surface of the silane-treated PTW nanocomposite had better interfacial adhesion, as the PTWs were covered with matrix resin.
{"title":"CHARACTERISATION OF EPOXY NANOCOMPOSITES REINFORCED BY POTASSIUM TITANATE WHISKER","authors":"Wan-Ting Sun, H. Takagi, A. N. Nakagaito","doi":"10.2495/HPSM180051","DOIUrl":"https://doi.org/10.2495/HPSM180051","url":null,"abstract":"The mechanical and physical properties of potassium titanate whisker (PTW) reinforced epoxy nanocomposites have been studied to examine the contribution of PTW loading and surface modification effects on these properties. Tensile tests and micro-hardness measurements have been used to study the mechanical performance of epoxy-based nanocomposites reinforced with 1 wt% to 5 wt% of PTW. We found that the mechanical properties and micro-hardness of PTW-reinforced epoxy nanocomposites become higher than those of neat epoxy resin. Furthermore, the experimental results showed that the nanocomposites reinforced with silane-treated PTW have higher tensile strength and Young’s modulus. The micro-hardness of the treated PTW nanocomposites also had higher values as compared with that of untreated PTW nanocomposites. These results indicate that the mechanical performances of the PTW/epoxy nanocomposites were controlled by the silane surface treatment. Scanning electron microscopy studies indicated that the fracture surface of the silane-treated PTW nanocomposite had better interfacial adhesion, as the PTWs were covered with matrix resin.","PeriodicalId":340058,"journal":{"name":"High Performance and Optimum Design of Structures and Materials III","volume":"05 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130267637","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}
Cast iron structures mostly date back to the second half of the 19th century. Material properties vary due to different composition and production techniques that have been used in different regions over decades. This is why it is of crucial importance to obtain case-specific information on properties of historic structures. Many historic metal structures do not fulfil requirements of present standards. Decisions about adequate construction interventions should be based on complex assessment of structural reliability. In this contribution, the material properties of an iron column are investigated and the key considerations for reliability assessment are presented. Three fundamental issues are addressed to optimise surveys and reliability assessments of cast iron columns: 1) an optimum number of material tests; 2) the selection between a finite element (FE) and analytical model; and 3) the target reliability level for a historic structure. It is shown that uncertainties due to limited test data, variability of material and geometrical properties, and resistance model uncertainty can be treated by a semi-probabilistic verification method. As a first approximation, five tensile tests might be considered as an optimum survey strategy. The application of FE models is more demanding than that of simplified analytical formulas, but it can better reflect structure-specific conditions and may increase structural resistance by about 15%. Optimum target reliability level for existing structures with a cultural heritage value could be lower than that for structural design and the assessment value of resistance may increase by about 20% for a reduced target level.
{"title":"OPTIMISING SURVEYS AND RELIABILITY ASSESSMENTS OF HISTORIC CAST-IRON COLUMNS","authors":"K. Jung, J. Marková, M. Sýkora","doi":"10.2495/HPSM180081","DOIUrl":"https://doi.org/10.2495/HPSM180081","url":null,"abstract":"Cast iron structures mostly date back to the second half of the 19th century. Material properties vary due to different composition and production techniques that have been used in different regions over decades. This is why it is of crucial importance to obtain case-specific information on properties of historic structures. Many historic metal structures do not fulfil requirements of present standards. Decisions about adequate construction interventions should be based on complex assessment of structural reliability. In this contribution, the material properties of an iron column are investigated and the key considerations for reliability assessment are presented. Three fundamental issues are addressed to optimise surveys and reliability assessments of cast iron columns: 1) an optimum number of material tests; 2) the selection between a finite element (FE) and analytical model; and 3) the target reliability level for a historic structure. It is shown that uncertainties due to limited test data, variability of material and geometrical properties, and resistance model uncertainty can be treated by a semi-probabilistic verification method. As a first approximation, five tensile tests might be considered as an optimum survey strategy. The application of FE models is more demanding than that of simplified analytical formulas, but it can better reflect structure-specific conditions and may increase structural resistance by about 15%. Optimum target reliability level for existing structures with a cultural heritage value could be lower than that for structural design and the assessment value of resistance may increase by about 20% for a reduced target level.","PeriodicalId":340058,"journal":{"name":"High Performance and Optimum Design of Structures and Materials III","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131320423","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}
Research presented in this paper utilizes public-sector buildings database obtained from the Croatian Energy Management Information System (EMIS) which comprises over 3,500 public sector buildings. EMIS provides a transparent oversight and control of energy consumption, making itself an inevitable tool for systematic energy management. The EMIS database holds static technical data of each facility, including general, constructional data, energy performance data and dynamic energy usage data. But there are a lot of variables in a database with data values that are impossible, i.e. have values that are not logical or outside of possible, acceptable ranges, and they are probably the consequence of user input errors. Besides this, there are also cases with missing data. As previously stated, this raises the question: Is it possible to make an algorithm for data cleansing and find a way to calculate the missing data? To use the obtained database for further, more complex, analysis like clustering, machine learning and neural network applications, it is necessary to remove extreme values from the database. Research presented in this paper deals with this problem with an emphasis on buildings constructional characteristics and proposes a cleansing algorithm. As a result a possible range of variables and procedure for replacement of invalid input values is proposed. Research results and findings can be used in similar buildings databases to optimize the datasets and exclude variables with extreme values which can significantly impact modelling process. Further, the proposed algorithm can be useful when making decisions for energy refurbishment and building maintenance since it eliminates cases from the database that have misleading data. The presented results show that in some cases there are more than 80% of missing or excluded data. Findings can also be implemented in EMIS or a similar system to avoid further entering of unacceptable data values.
{"title":"ALGORITHM FOR CONSTRUCTIONAL CHARACTERISTICS DATA CLEANSING OF LARGE-SCALE PUBLIC BUILDINGS DATABASE","authors":"Hrvoje Krstić, M. Teni","doi":"10.2495/HPSM180221","DOIUrl":"https://doi.org/10.2495/HPSM180221","url":null,"abstract":"Research presented in this paper utilizes public-sector buildings database obtained from the Croatian Energy Management Information System (EMIS) which comprises over 3,500 public sector buildings. EMIS provides a transparent oversight and control of energy consumption, making itself an inevitable tool for systematic energy management. The EMIS database holds static technical data of each facility, including general, constructional data, energy performance data and dynamic energy usage data. But there are a lot of variables in a database with data values that are impossible, i.e. have values that are not logical or outside of possible, acceptable ranges, and they are probably the consequence of user input errors. Besides this, there are also cases with missing data. As previously stated, this raises the question: Is it possible to make an algorithm for data cleansing and find a way to calculate the missing data? To use the obtained database for further, more complex, analysis like clustering, machine learning and neural network applications, it is necessary to remove extreme values from the database. Research presented in this paper deals with this problem with an emphasis on buildings constructional characteristics and proposes a cleansing algorithm. As a result a possible range of variables and procedure for replacement of invalid input values is proposed. Research results and findings can be used in similar buildings databases to optimize the datasets and exclude variables with extreme values which can significantly impact modelling process. Further, the proposed algorithm can be useful when making decisions for energy refurbishment and building maintenance since it eliminates cases from the database that have misleading data. The presented results show that in some cases there are more than 80% of missing or excluded data. Findings can also be implemented in EMIS or a similar system to avoid further entering of unacceptable data values.","PeriodicalId":340058,"journal":{"name":"High Performance and Optimum Design of Structures and Materials III","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123205724","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 is concerned with the evaluation of tensile strength of annealed and heat-strengthened glass from a given set of samples. The values of tensile stresses at failure corresponding to the strengths of samples are determined from experimentally measured strains and also computed numerically using the known value of the critical load and loading scenario only. In contrast to common testing procedures performed on monolithic glass samples, laminated glass specimens are analyzed in our study to account for a potential impact of the process of fabrication. The data sets from two types of experiments are examined. In particular, the measured response from four-point bending tests is complemented with that for simply-supported laminated glass samples loaded in bending by a uniformly distributed pressure. The experimentally measured data are compared with those derived numerically to support the proposed computational model. In this regard, the results of small scale testing needed in calibrating the constitutive model of the polymer interlayer are also discussed in connection to ethylen-vinyl acetate and polyvinyl butyral foils.
{"title":"EVALUATION OF TENSILE STRENGTH OF GLASS FROM COMBINED EXPERIMENTAL AND NUMERICAL ANALYSIS OF LAMINATED GLASS","authors":"A. Zemanová, Jaroslav Schmidt, M. Šejnoha","doi":"10.2495/HPSM180041","DOIUrl":"https://doi.org/10.2495/HPSM180041","url":null,"abstract":"This paper is concerned with the evaluation of tensile strength of annealed and heat-strengthened glass from a given set of samples. The values of tensile stresses at failure corresponding to the strengths of samples are determined from experimentally measured strains and also computed numerically using the known value of the critical load and loading scenario only. In contrast to common testing procedures performed on monolithic glass samples, laminated glass specimens are analyzed in our study to account for a potential impact of the process of fabrication. The data sets from two types of experiments are examined. In particular, the measured response from four-point bending tests is complemented with that for simply-supported laminated glass samples loaded in bending by a uniformly distributed pressure. The experimentally measured data are compared with those derived numerically to support the proposed computational model. In this regard, the results of small scale testing needed in calibrating the constitutive model of the polymer interlayer are also discussed in connection to ethylen-vinyl acetate and polyvinyl butyral foils.","PeriodicalId":340058,"journal":{"name":"High Performance and Optimum Design of Structures and Materials III","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134433802","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}
Modelling and predictions of road traffic emissions and ground-borne vibrations caused by vehicles driving over different types of road bumps has become a rapidly developing research area. However, due to the lack of effective methods and indicators that would define traffic behavior, the accuracy of emissions and vibrations with such an approach is often not at the appropriate level. This paper presents the attempt to model and predict harmful road traffic emissions and vibrations using microsimulation traffic tools and emission models on one side and hybrid optimized models based on artificial neural networks and neuro-fuzzy techniques on the other. The optimized ANFIS-based model was developed to predict harmful road traffic emissions. Basic data were obtained with two programs: VISSIM for micro simulation of traffic flow and ENVIVER to calculate the corresponding emissions at vehicle level. The predicted NOx values indicate a significant increase of emissions by vehicles driving over road bumps, which is almost 100% higher than normal driving. The evaluation and prediction of ground-borne vibrations focused on heavy-duty vehicles, which usually cause perceptible levels of ground-borne vibrations. The prognosis of ground-borne vibration was made with local measurements and empirical vibration predictors. The predicted vibration levels caused by heavy-duty vehicles driving over road bumps are up to 24 times higher than normal vehicle driving (sinusoidal bump). Research shows that setting up speed bumps in different locations in urban areas has to be carefully examined because the level of harmful emissions and ground-borne vibrations increase.
{"title":"ANFIS PREDICTION AND MODELLING OF HARMFUL EFFECTS ON THE ENVIRONMENT PRODUCED BY VEHICLES CROSSING ROAD BUMPS","authors":"S. Toplak, D. Sever","doi":"10.2495/HPSM180211","DOIUrl":"https://doi.org/10.2495/HPSM180211","url":null,"abstract":"Modelling and predictions of road traffic emissions and ground-borne vibrations caused by vehicles driving over different types of road bumps has become a rapidly developing research area. However, due to the lack of effective methods and indicators that would define traffic behavior, the accuracy of emissions and vibrations with such an approach is often not at the appropriate level. This paper presents the attempt to model and predict harmful road traffic emissions and vibrations using microsimulation traffic tools and emission models on one side and hybrid optimized models based on artificial neural networks and neuro-fuzzy techniques on the other. The optimized ANFIS-based model was developed to predict harmful road traffic emissions. Basic data were obtained with two programs: VISSIM for micro simulation of traffic flow and ENVIVER to calculate the corresponding emissions at vehicle level. The predicted NOx values indicate a significant increase of emissions by vehicles driving over road bumps, which is almost 100% higher than normal driving. The evaluation and prediction of ground-borne vibrations focused on heavy-duty vehicles, which usually cause perceptible levels of ground-borne vibrations. The prognosis of ground-borne vibration was made with local measurements and empirical vibration predictors. The predicted vibration levels caused by heavy-duty vehicles driving over road bumps are up to 24 times higher than normal vehicle driving (sinusoidal bump). Research shows that setting up speed bumps in different locations in urban areas has to be carefully examined because the level of harmful emissions and ground-borne vibrations increase.","PeriodicalId":340058,"journal":{"name":"High Performance and Optimum Design of Structures and Materials III","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132119689","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 paper deals with the cost optimization of a cantilever roof structure, designed for a small football stadium in Limbuš, located close to the city of Maribor, Slovenia. The structure was proposed to be designed from steel I sections for columns, beams and struts, and from reinforced concrete bases. The cost optimization of the structure was calculated by the Mixed-Integer Non-linear Programming (MINLP). The MINLP optimization model of the structure was developed. A cost objective function was applied and subjected to the design, resistance and deflection constraints. The dimensioning constraints were defined in accordance with Eurocodes 2 and 3. The Modified Outer-Approximation/ Equality-Relaxation (OA/ER) algorithm was used.
{"title":"COST OPTIMIZATION OF A CANTILEVER ROOF STRUCTURE FOR A SMALL FOOTBALL STADIUM IN LIMBUŠ, SLOVENIA","authors":"T. Zula, S. Kravanja","doi":"10.2495/HPSM180181","DOIUrl":"https://doi.org/10.2495/HPSM180181","url":null,"abstract":"The paper deals with the cost optimization of a cantilever roof structure, designed for a small football stadium in Limbuš, located close to the city of Maribor, Slovenia. The structure was proposed to be designed from steel I sections for columns, beams and struts, and from reinforced concrete bases. The cost optimization of the structure was calculated by the Mixed-Integer Non-linear Programming (MINLP). The MINLP optimization model of the structure was developed. A cost objective function was applied and subjected to the design, resistance and deflection constraints. The dimensioning constraints were defined in accordance with Eurocodes 2 and 3. The Modified Outer-Approximation/ Equality-Relaxation (OA/ER) algorithm was used.","PeriodicalId":340058,"journal":{"name":"High Performance and Optimum Design of Structures and Materials III","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115432620","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}
Titanium’s accelerating usage in global markets is attributable to its distinctive combination of physical and metallurgical properties. The key to best utilizing titanium is to exploit these characteristics, especially as they complement one another in a given application, rather than to just directly substitute titanium for another metal. Present essay try to show some of the most important aspects concerning the industrial use of Titanium and its alloys. Starting with those regarding its properties, continuing with some technological processes involved in elaborating those materials and ending with the issues regarding recycling processes, titanium challenges scientists and engineers as well because of its remarkable properties that allow special applications in various human activities; but the main issues regarding the technological process of elaborating Titanium or its alloys are followed by those connected with the environments protection and recycling those materials. It seams that titanium worth all those efforts made by scientists in using it at a larger scale. Researches on those aspects are developed in Romania too.
{"title":"ULTRASONIC GRAIN NOISE MODELLING APPLICATIONS TO TITANIUM ALLOY INSPECTION","authors":"Theodor Trancă, I. Radu","doi":"10.2495/HPSM180031","DOIUrl":"https://doi.org/10.2495/HPSM180031","url":null,"abstract":"Titanium’s accelerating usage in global markets is attributable to its distinctive combination of physical and metallurgical properties. The key to best utilizing titanium is to exploit these characteristics, especially as they complement one another in a given application, rather than to just directly substitute titanium for another metal. Present essay try to show some of the most important aspects concerning the industrial use of Titanium and its alloys. Starting with those regarding its properties, continuing with some technological processes involved in elaborating those materials and ending with the issues regarding recycling processes, titanium challenges scientists and engineers as well because of its remarkable properties that allow special applications in various human activities; but the main issues regarding the technological process of elaborating Titanium or its alloys are followed by those connected with the environments protection and recycling those materials. It seams that titanium worth all those efforts made by scientists in using it at a larger scale. Researches on those aspects are developed in Romania too.","PeriodicalId":340058,"journal":{"name":"High Performance and Optimum Design of Structures and Materials III","volume":"112 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124771608","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 study investigated alkali treatment effects on tensile properties of plain woven jute-fiberreinforced green composites under thermal fatigue. Concentrations of the alkali treatment were 1% and 15%. Thermal fatigue tests of non-treated and alkali-treated green composites and polylactic acid (PLA) were conducted at temperatures of 35–80°C. The maximum number of cycles was 103 cycles. Quasi-static tensile tests were conducted using non-treated and alkali-treated green composite and PLA samples after thermal fatigue. Surfaces of non-treated and alkali-treated jute fibers were observed. Results show the following. Tensile strength of non-treated green composite decreased along with an increased number of cycles. Tensile strengths of 1% and 15% alkali-treated green composites exhibited almost no change until 102 cycles. Young’s moduli of non-treated and 1% and 15% alkali-treated green composites exhibited almost no change until 102 cycles. Tensile strengths of 1% and 15% alkali-treated green composites at 103 cycles were lower than those of 1% and 15% alkali-treated green composites at 102 cycles. Furthermore, Young’s moduli of non-treated and 1% and 15% alkali-treated green composites at 103 cycles were lower than those of non-treated, 1% and 15% alkali-treated green composites at 102 cycles. Tensile properties of PLA remained almost unchanged under thermal fatigue. Surface observations revealed a smooth surface of non-treated jute fiber. However, surfaces of 1% and 15% alkali-treated jute fiber were not smooth. Therefore, tensile strength of green composite under thermal fatigue can be improved by surface roughness of 1% and 15% alkali-treated jute fiber up to 102 cycles.
{"title":"THERMAL FATIGUE EFFECTS ON TENSILE PROPERTIES OF SURFACE-TREATED NATURAL FIBER/POLYLACTIC ACID GREEN COMPOSITE","authors":"H. Katogi, K. Takemura, Shun-Ichiro Kawasaki","doi":"10.2495/HPSM180071","DOIUrl":"https://doi.org/10.2495/HPSM180071","url":null,"abstract":"This study investigated alkali treatment effects on tensile properties of plain woven jute-fiberreinforced green composites under thermal fatigue. Concentrations of the alkali treatment were 1% and 15%. Thermal fatigue tests of non-treated and alkali-treated green composites and polylactic acid (PLA) were conducted at temperatures of 35–80°C. The maximum number of cycles was 103 cycles. Quasi-static tensile tests were conducted using non-treated and alkali-treated green composite and PLA samples after thermal fatigue. Surfaces of non-treated and alkali-treated jute fibers were observed. Results show the following. Tensile strength of non-treated green composite decreased along with an increased number of cycles. Tensile strengths of 1% and 15% alkali-treated green composites exhibited almost no change until 102 cycles. Young’s moduli of non-treated and 1% and 15% alkali-treated green composites exhibited almost no change until 102 cycles. Tensile strengths of 1% and 15% alkali-treated green composites at 103 cycles were lower than those of 1% and 15% alkali-treated green composites at 102 cycles. Furthermore, Young’s moduli of non-treated and 1% and 15% alkali-treated green composites at 103 cycles were lower than those of non-treated, 1% and 15% alkali-treated green composites at 102 cycles. Tensile properties of PLA remained almost unchanged under thermal fatigue. Surface observations revealed a smooth surface of non-treated jute fiber. However, surfaces of 1% and 15% alkali-treated jute fiber were not smooth. Therefore, tensile strength of green composite under thermal fatigue can be improved by surface roughness of 1% and 15% alkali-treated jute fiber up to 102 cycles.","PeriodicalId":340058,"journal":{"name":"High Performance and Optimum Design of Structures and Materials III","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127503758","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, a comparative study of numerical formulations for the analysis of soil-pile interaction is presented. These formulations consist of the coupling of the Boundary Element Method (BEM) with the Finite Element Method (FEM). The pile may be subjected to horizontal or moment loading applied to its top. The soil is supposed to be a semi-infinite, elastic, isotropic continuum and is modeled by BEM. The pile is either represented by a single finite element or as a number of usual beam finite elements and the pile-soil interface tractions are represented by constant, linear, quartic and high-degree polynomial functions. Examples of individual piles subjected to horizontal loading are analyzed with the formulations presented, and the displacements and the diagram of the bending moments along the pile are compared.
{"title":"BEM/FEM FORMULATIONS FOR THE ANALYSIS OF PILES SUBMITTED TO HORIZONTAL LOADS","authors":"Endi Samba Luamba, J. B. Paiva","doi":"10.2495/HPSM180231","DOIUrl":"https://doi.org/10.2495/HPSM180231","url":null,"abstract":"In this work, a comparative study of numerical formulations for the analysis of soil-pile interaction is presented. These formulations consist of the coupling of the Boundary Element Method (BEM) with the Finite Element Method (FEM). The pile may be subjected to horizontal or moment loading applied to its top. The soil is supposed to be a semi-infinite, elastic, isotropic continuum and is modeled by BEM. The pile is either represented by a single finite element or as a number of usual beam finite elements and the pile-soil interface tractions are represented by constant, linear, quartic and high-degree polynomial functions. Examples of individual piles subjected to horizontal loading are analyzed with the formulations presented, and the displacements and the diagram of the bending moments along the pile are compared.","PeriodicalId":340058,"journal":{"name":"High Performance and Optimum Design of Structures and Materials III","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128927470","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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