Pub Date : 2019-08-31DOI: 10.31814/stce.nuce2019-13(3)-06
N. Lieu, N. Hung
In this study, for the first time an isogeometric finite element formulation for bending analysis of functionally graded porous (FGP) plates reinforced by graphene platelets (GPLs) embedded in piezoelectric layers is presented. It is named as PFGP-GPLs for a short. The plates are constituted by a core layer, which contains the internal pores and GPLs dispersed in the metal matrix either uniformly or non-uniformly according to three different patterns, and two piezoelectric layers perfectly bonded on the top and bottom surfaces of host plate. The modified Halpin–Tsai micromechanical model is used to estimate the effective mechanical properties which vary continuously along thickness direction of the core layer. In addition, the electric potential is assumed to vary linearly through the thickness for each piezoelectric sublayer. A generalized C0-type higher-order shear deformation theory (C0-HSDT) in association with isogeometric analysis (IGA) is investigated. The effects of weight fractions and dispersion patterns of GPLs, the coefficient and distribution types of porosity as well as external electrical voltages on structure’s behaviors are investigated through several numerical examples. Keywords: piezoelectric materials; FG-porous plate; graphene platelet reinforcements; isogeometric analysis.
{"title":"Static analysis of piezoelectric functionally graded porous plates reinforced by graphene platelets","authors":"N. Lieu, N. Hung","doi":"10.31814/stce.nuce2019-13(3)-06","DOIUrl":"https://doi.org/10.31814/stce.nuce2019-13(3)-06","url":null,"abstract":"In this study, for the first time an isogeometric finite element formulation for bending analysis of functionally graded porous (FGP) plates reinforced by graphene platelets (GPLs) embedded in piezoelectric layers is presented. It is named as PFGP-GPLs for a short. The plates are constituted by a core layer, which contains the internal pores and GPLs dispersed in the metal matrix either uniformly or non-uniformly according to three different patterns, and two piezoelectric layers perfectly bonded on the top and bottom surfaces of host plate. The modified Halpin–Tsai micromechanical model is used to estimate the effective mechanical properties which vary continuously along thickness direction of the core layer. In addition, the electric potential is assumed to vary linearly through the thickness for each piezoelectric sublayer. A generalized C0-type higher-order shear deformation theory (C0-HSDT) in association with isogeometric analysis (IGA) is investigated. The effects of weight fractions and dispersion patterns of GPLs, the coefficient and distribution types of porosity as well as external electrical voltages on structure’s behaviors are investigated through several numerical examples. \u0000Keywords: \u0000piezoelectric materials; FG-porous plate; graphene platelet reinforcements; isogeometric analysis.","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87166748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-31DOI: 10.31814/stce.nuce2019-13(3)-07
Dinh Van Thuat, Nguyen Dinh Hoa, H. Chuong, Truong Viet Hung
Single-storey industrial steel frames with crances are considered as being vertically irregular in structural configuration and load distribution under strong earthquake excitations. In this paper, various analytical frames with their spans of 20, 26, 32 and 38 m and locations built in Ha Noi and Son La regions were designed to resist dead, roof live, crane and wind loads. The equivalent horizontal and vertical static earthquake loads applied on the frames were determined. Next, by using linear elastic analyses of structures, the effects of vertical seismic actions on the responses of the frames were evaluated in terms of the ratios K1 and K2 at the bottom and top of the columns corresponding to different combinations of dead loads and static earthquake loads, as denoted by CE1, CE2 and CE3. The effects of seismic actions compared with those of wind actions were also evaluated in terms of the ratios K3 and K4. As a result, the effects of vertical seismic actions were significant and increased with the span lengths of the frames. In addition, by using nonlinear inelastic analyses of structures, the levels of the static earthquake loads were determined corresponding to the first yielding and maximum resistances of the frames. Keywords: single-storey industrial buildings; steel frames; span lengths; irregularity; vertical seismic actions; earthquake levels; wind loads
{"title":"Effects of vertical seismic actions on the responses of single-storey industrial steel building frames","authors":"Dinh Van Thuat, Nguyen Dinh Hoa, H. Chuong, Truong Viet Hung","doi":"10.31814/stce.nuce2019-13(3)-07","DOIUrl":"https://doi.org/10.31814/stce.nuce2019-13(3)-07","url":null,"abstract":"Single-storey industrial steel frames with crances are considered as being vertically irregular in structural configuration and load distribution under strong earthquake excitations. In this paper, various analytical frames with their spans of 20, 26, 32 and 38 m and locations built in Ha Noi and Son La regions were designed to resist dead, roof live, crane and wind loads. The equivalent horizontal and vertical static earthquake loads applied on the frames were determined. Next, by using linear elastic analyses of structures, the effects of vertical seismic actions on the responses of the frames were evaluated in terms of the ratios K1 and K2 at the bottom and top of the columns corresponding to different combinations of dead loads and static earthquake loads, as denoted by CE1, CE2 and CE3. The effects of seismic actions compared with those of wind actions were also evaluated in terms of the ratios K3 and K4. As a result, the effects of vertical seismic actions were significant and increased with the span lengths of the frames. In addition, by using nonlinear inelastic analyses of structures, the levels of the static earthquake loads were determined corresponding to the first yielding and maximum resistances of the frames. \u0000Keywords: \u0000single-storey industrial buildings; steel frames; span lengths; irregularity; vertical seismic actions; earthquake levels; wind loads","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73340392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-31DOI: 10.31814/stce.nuce2019-13(3)-03
T. Mien, Nguyễn Hoàng Phúc, C. T. Yen
In recent years, fly ash (FA) has been increasingly used widespread like a mineral admixture for the production of concrete in general and self-compacting concrete (SCC) in particular. Fly ash is an industrial by-product and is generated during the combustion of coal for energy production from the thermal power station. Fly ash is utilized to increase the workability of concrete mixtures and increase shrinkage resistance of the self-compacting concrete. In this paper, the mixture design of the self-compacting concrete with strength grade of 60 MPa is performed with requirement that the workability satisfies the slump flow, T500 and the V-Funnel TV test range from 650 to 800 mm, from 2 to 5 s and from 6 to 12 s, respectively. Besides, fly ash is used to replace cement with content of 15%, 25%, 35% and 50% to evaluate shrinkage resistance. The obtained results showed that using fly ash contents from 25% to 35% to replace cement can ensure workability of the mixture together with high degree of shrinkage restraint. According to ASTM C1581, the evaluation of restrained shrinkage of the self-compacting concrete based on the restrained ring test, this method reduces the testing time but still ensure the reliability. Keywords: fly ash; self-compacting concrete; shrinkage resistance; restrained ring test.
{"title":"Effect of fly ash on shrinkage of self-compacting concrete using restrained ring test","authors":"T. Mien, Nguyễn Hoàng Phúc, C. T. Yen","doi":"10.31814/stce.nuce2019-13(3)-03","DOIUrl":"https://doi.org/10.31814/stce.nuce2019-13(3)-03","url":null,"abstract":"In recent years, fly ash (FA) has been increasingly used widespread like a mineral admixture for the production of concrete in general and self-compacting concrete (SCC) in particular. Fly ash is an industrial by-product and is generated during the combustion of coal for energy production from the thermal power station. Fly ash is utilized to increase the workability of concrete mixtures and increase shrinkage resistance of the self-compacting concrete. In this paper, the mixture design of the self-compacting concrete with strength grade of 60 MPa is performed with requirement that the workability satisfies the slump flow, T500 and the V-Funnel TV test range from 650 to 800 mm, from 2 to 5 s and from 6 to 12 s, respectively. Besides, fly ash is used to replace cement with content of 15%, 25%, 35% and 50% to evaluate shrinkage resistance. The obtained results showed that using fly ash contents from 25% to 35% to replace cement can ensure workability of the mixture together with high degree of shrinkage restraint. According to ASTM C1581, the evaluation of restrained shrinkage of the self-compacting concrete based on the restrained ring test, this method reduces the testing time but still ensure the reliability. \u0000Keywords: \u0000fly ash; self-compacting concrete; shrinkage resistance; restrained ring test.","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73728893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-31DOI: 10.31814/stce.nuce2019-13(3)-05
Chau-Dinh Thanh, H. Con, Le Phuong Binh
In this research, the smoothed finite element methods (S-FEM) based on the edge-based (ES) and node-based (NS) approaches are combined to develop for the 3-node triangular plate element which uses the mixed interpolation of tensorial components (MITC3) technique to remove the shear-locking phenomenon. This approach is based on the βFEM in which the parameter β is used to tune the contribution ratio of the edge-based and node-based smoothed domains. The strain fields of the proposed ES+NS-MITC3 element are smoothed on a part of the edge-based domains and the other on the node-based domains which are respectively defined by elements sharing common edges and common nodes. The ES+NS-MITC3 element passes the patch test and is employed to statically analyze some benchmark Reissner-Mindlin plates, including square and rhombus ones. Numerical results show that, in both thin and thick plates the ES+NS-MITC3 element can give results better than similar elements using the ES-FEM or NS-FEM only.
{"title":"Static analysis of Reissner-Mindlin plates using ES+NS-MITC3 elements","authors":"Chau-Dinh Thanh, H. Con, Le Phuong Binh","doi":"10.31814/stce.nuce2019-13(3)-05","DOIUrl":"https://doi.org/10.31814/stce.nuce2019-13(3)-05","url":null,"abstract":"In this research, the smoothed finite element methods (S-FEM) based on the edge-based (ES) and node-based (NS) approaches are combined to develop for the 3-node triangular plate element which uses the mixed interpolation of tensorial components (MITC3) technique to remove the shear-locking phenomenon. This approach is based on the βFEM in which the parameter β is used to tune the contribution ratio of the edge-based and node-based smoothed domains. The strain fields of the proposed ES+NS-MITC3 element are smoothed on a part of the edge-based domains and the other on the node-based domains which are respectively defined by elements sharing common edges and common nodes. The ES+NS-MITC3 element passes the patch test and is employed to statically analyze some benchmark Reissner-Mindlin plates, including square and rhombus ones. Numerical results show that, in both thin and thick plates the ES+NS-MITC3 element can give results better than similar elements using the ES-FEM or NS-FEM only. ","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88559289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-31DOI: 10.31814/stce.nuce2019-13(3)-12
N. V. Chung
This paper presents an efficient and accurate numerical technique based upon the scaled boundary finite element method for the analysis of two-dimensional, linear, second-order, boundary value problems with the domain completely described by a circular defining curve. The scaled boundary finite element formulation is established in a general framework allowing single-field and multi-field problems, bounded and unbounded bodies, distributed body source, and general boundary conditions to be treated in a unified fashion. The conventional polar coordinates together with a properly selected scaling center are utilized to achieve the exact description of the circular defining curve, exact geometry of the domain, and exact spatial differential operators. The computational performance of the implemented procedure is then fully investigated for various scenarios within the context of geo-mechanics applications. Keywords: exact geometry; geo-mechanics; multi-field problems; SBFEM; scaled boundary coordinates.
{"title":"Scaled boundary finite element method with circular defining curve for geo-mechanics applications","authors":"N. V. Chung","doi":"10.31814/stce.nuce2019-13(3)-12","DOIUrl":"https://doi.org/10.31814/stce.nuce2019-13(3)-12","url":null,"abstract":"This paper presents an efficient and accurate numerical technique based upon the scaled boundary finite element method for the analysis of two-dimensional, linear, second-order, boundary value problems with the domain completely described by a circular defining curve. The scaled boundary finite element formulation is established in a general framework allowing single-field and multi-field problems, bounded and unbounded bodies, distributed body source, and general boundary conditions to be treated in a unified fashion. The conventional polar coordinates together with a properly selected scaling center are utilized to achieve the exact description of the circular defining curve, exact geometry of the domain, and exact spatial differential operators. The computational performance of the implemented procedure is then fully investigated for various scenarios within the context of geo-mechanics applications. \u0000Keywords: \u0000exact geometry; geo-mechanics; multi-field problems; SBFEM; scaled boundary coordinates.","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77049024","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, instrumented indentation testing was conducted at room temperature for the investigation of the effect of strain rate on the hardness and yield strength in the weld zone of a commonly used structural steel, SM520. A number of indentation tests were undertaken at a number of strain rate values from 0.02 s-1 to 0.2 s-1 in the weld metal (WM), heat-affected zone (HAZ), and base metal (BM) regions of the weld zone. The mechanical properties including yield strength (σy) and hardness (H) in WM, HAZ, and BM were then computed from the applied load-penetration depth curves using a proposed method. As the result, the effects of strain rate indentation on yield strength and hardness in all regions of the weld zone were evaluated. The results displayed that hardness and yield strength in the weld zone’s components are influenced on the strain rate, where both hardness and yield strength decrease with the decreasing strain rate. Keywords: indentation; mechanical properties; strain rate effect; structural steel; weld zone.
{"title":"Indentation for investigation of strain rate effect on mechanical properties in structural steel weld zone","authors":"Pham Thai Hoan, Nguyễn Ngọc Vinh, Nguyen Thi Thanh Tung","doi":"10.31814/stce.nuce2019-13(3)-10","DOIUrl":"https://doi.org/10.31814/stce.nuce2019-13(3)-10","url":null,"abstract":"In this study, instrumented indentation testing was conducted at room temperature for the investigation of the effect of strain rate on the hardness and yield strength in the weld zone of a commonly used structural steel, SM520. A number of indentation tests were undertaken at a number of strain rate values from 0.02 s-1 to 0.2 s-1 in the weld metal (WM), heat-affected zone (HAZ), and base metal (BM) regions of the weld zone. The mechanical properties including yield strength (σy) and hardness (H) in WM, HAZ, and BM were then computed from the applied load-penetration depth curves using a proposed method. As the result, the effects of strain rate indentation on yield strength and hardness in all regions of the weld zone were evaluated. The results displayed that hardness and yield strength in the weld zone’s components are influenced on the strain rate, where both hardness and yield strength decrease with the decreasing strain rate. \u0000Keywords: \u0000indentation; mechanical properties; strain rate effect; structural steel; weld zone.","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87984409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-04-30DOI: 10.31814/STCE.NUCE2019-13(2)-05
P. H. Anh, T. Dương
In this article, an efficient numerical approach for weight optimisation of functionally graded (FG) beams in the presence of frequency constraints is presented. For the analysis purpose, a finite element (FE) solution based on the first order shear deformation theory (FSDT) is established to analyse the free vibration behaviour of FG beams. A four-parameter power law distribution and a five-parameter trigonometric distribution are used to describe the volume fraction of material constituents in the thickness direction. The goal is to tailor the thickness and material distribution for minimising the weight of FG beams while constraining the fundamental frequency to be greater than a prescribed value. The constrained optimisation problem is effectively solved by a novel differential evolution (DE) algorithm. The validity and efficiency of the proposed approach is demonstrated through two numerical examples corresponding to the four-parameter distribution and the five-parameter distribution.Keywords: FGM beam; lightweight design; frequency constraint; differential evolution.
{"title":"Weight optimisation of functionally graded beams using modified differential evolution","authors":"P. H. Anh, T. Dương","doi":"10.31814/STCE.NUCE2019-13(2)-05","DOIUrl":"https://doi.org/10.31814/STCE.NUCE2019-13(2)-05","url":null,"abstract":"In this article, an efficient numerical approach for weight optimisation of functionally graded (FG) beams in the presence of frequency constraints is presented. For the analysis purpose, a finite element (FE) solution based on the first order shear deformation theory (FSDT) is established to analyse the free vibration behaviour of FG beams. A four-parameter power law distribution and a five-parameter trigonometric distribution are used to describe the volume fraction of material constituents in the thickness direction. The goal is to tailor the thickness and material distribution for minimising the weight of FG beams while constraining the fundamental frequency to be greater than a prescribed value. The constrained optimisation problem is effectively solved by a novel differential evolution (DE) algorithm. The validity and efficiency of the proposed approach is demonstrated through two numerical examples corresponding to the four-parameter distribution and the five-parameter distribution.Keywords: FGM beam; lightweight design; frequency constraint; differential evolution.","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75035235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-04-30DOI: 10.31814/STCE.NUCE2019-13(2)-03
N. Hải, L. Binh, Doan Ngoc Tinh Nghiem, Ngo-Huu Cuong
A corotational finite element for large-displacement elastic analysis of semi-rigid planar steel frames is proposed in this paper. Two zero-length rotational springs are attached to the ends of the Euler-Bernoulli element formulated in corotational context to simulate the flexibility of the beam-to-column connections and then the equilibrium equations of the hybrid element, including the stiffness matrix which contains the stiffness terms of the rotational springs, are established based on the static condensation procedure. The linear and Kishi-Chen three-parameter power models are applied in modelling the moment-rotation relation of beam-column connections. The arc-length nonlinear algorithm combined with the sign of displacement internal product are used to predict the equilibrium paths of the system under static load. The analysis results are compared to previous studies to verify the accuracy and effectiveness of the proposed element and the applied nonlinear procedure. Keywords: corotational context; Euler-Bernoulli element; large displacement; semi-rigid connection; steel frame; static analysis.
{"title":"Large displacement elastic static analysis of semi-rigid planar steel frames by corotational Euler--Bernoulli finite element","authors":"N. Hải, L. Binh, Doan Ngoc Tinh Nghiem, Ngo-Huu Cuong","doi":"10.31814/STCE.NUCE2019-13(2)-03","DOIUrl":"https://doi.org/10.31814/STCE.NUCE2019-13(2)-03","url":null,"abstract":"A corotational finite element for large-displacement elastic analysis of semi-rigid planar steel frames is proposed in this paper. Two zero-length rotational springs are attached to the ends of the Euler-Bernoulli element formulated in corotational context to simulate the flexibility of the beam-to-column connections and then the equilibrium equations of the hybrid element, including the stiffness matrix which contains the stiffness terms of the rotational springs, are established based on the static condensation procedure. The linear and Kishi-Chen three-parameter power models are applied in modelling the moment-rotation relation of beam-column connections. The arc-length nonlinear algorithm combined with the sign of displacement internal product are used to predict the equilibrium paths of the system under static load. The analysis results are compared to previous studies to verify the accuracy and effectiveness of the proposed element and the applied nonlinear procedure. \u0000Keywords: corotational context; Euler-Bernoulli element; large displacement; semi-rigid connection; steel frame; static analysis.","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74632450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-04-30DOI: 10.31814/STCE.NUCE2019-13(2)-07
Hoang Vinh Long
In the world, waste glass is widely recycled, especially in developed countries with a recycling rate of about 30-90%. Currently, in Vietnam glass emissions in urban areas account for 1.5-2% of solid wastes; however, few studies mention this waste. Therefore, light weight concrete (LWC) using foam glass granulates (FGG) is the object of this paper. In the study, the raw materials are FGG, But Son PC40 cement, Pha Lai fly ash and Sikament superplasticizer named R4. The experimental results show that with FGG content of 50% (by volume), the LWC’s bulk specific gravity is 1302 kg/m3 and compressive strength at 28 days is 89 kG/cm2. Keywords: waste glass; foam glass granulate; light weight concrete.
在世界范围内，废玻璃被广泛回收利用，特别是在发达国家，回收率约为30-90%。目前，在越南，城市地区的玻璃排放量占固体废物的1.5-2%;然而，很少有研究提到这种浪费。因此，采用泡沫玻璃颗粒(FGG)的轻质混凝土(LWC)是本文的研究对象。本研究以FGG、But Son PC40水泥、Pha Lai粉煤灰和sikment高效减水剂R4为原料。实验结果表明，当FGG含量为50%(体积比)时，LWC的体积比重为1302 kg/m3, 28天抗压强度为89 kg/ cm2。关键词:废玻璃;泡沫玻璃颗粒;轻质混凝土。
{"title":"Study on producing light weight concrete with foam glass granules","authors":"Hoang Vinh Long","doi":"10.31814/STCE.NUCE2019-13(2)-07","DOIUrl":"https://doi.org/10.31814/STCE.NUCE2019-13(2)-07","url":null,"abstract":"In the world, waste glass is widely recycled, especially in developed countries with a recycling rate of about 30-90%. Currently, in Vietnam glass emissions in urban areas account for 1.5-2% of solid wastes; however, few studies mention this waste. Therefore, light weight concrete (LWC) using foam glass granulates (FGG) is the object of this paper. In the study, the raw materials are FGG, But Son PC40 cement, Pha Lai fly ash and Sikament superplasticizer named R4. The experimental results show that with FGG content of 50% (by volume), the LWC’s bulk specific gravity is 1302 kg/m3 and compressive strength at 28 days is 89 kG/cm2. \u0000Keywords: waste glass; foam glass granulate; light weight concrete.","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74119903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-04-30DOI: 10.31814/STCE.NUCE2019-13(2)-06
N. Trung
Identification of dynamic structural characteristics such as natural frequency based on measured vibration responses at site is one of the important steps in the structural investigation work of loading test and structural health monitoring. During the service stage, the dynamic characteristics can be changed due to the stiffness reduction and nonlinear of structure under extrema excitation. Therefore, the identification of instantaneous parameters of structure is very necessary in detecting and monitoring the structural deterioration continuously by the time. This paper presents the data processing method using Hilbert Huang Transform (HHT) algorithm in determining a time-dependent frequencies of steel frame. The vibration experiment for steel frame was conducted in this study. The acceleration responses in time domain were recorded and analyzed by HTT to determine the fundamental natural frequencies of frame. The instantaneous frequencies in the time domain of steel frame are the main finding in this research. The traditional data processing method using a Fast Fourier Transform (FFT) was conducted and compared with the HHT method. Keywords: Hilbert Huang Transform (HHT); steel frame; Fast Fourier Transform (FFT); natural frequency.
{"title":"Application of Hilbert Huang transform to identify the natural frequencies of steel frame","authors":"N. Trung","doi":"10.31814/STCE.NUCE2019-13(2)-06","DOIUrl":"https://doi.org/10.31814/STCE.NUCE2019-13(2)-06","url":null,"abstract":"Identification of dynamic structural characteristics such as natural frequency based on measured vibration responses at site is one of the important steps in the structural investigation work of loading test and structural health monitoring. During the service stage, the dynamic characteristics can be changed due to the stiffness reduction and nonlinear of structure under extrema excitation. Therefore, the identification of instantaneous parameters of structure is very necessary in detecting and monitoring the structural deterioration continuously by the time. This paper presents the data processing method using Hilbert Huang Transform (HHT) algorithm in determining a time-dependent frequencies of steel frame. The vibration experiment for steel frame was conducted in this study. The acceleration responses in time domain were recorded and analyzed by HTT to determine the fundamental natural frequencies of frame. The instantaneous frequencies in the time domain of steel frame are the main finding in this research. The traditional data processing method using a Fast Fourier Transform (FFT) was conducted and compared with the HHT method. \u0000Keywords: Hilbert Huang Transform (HHT); steel frame; Fast Fourier Transform (FFT); natural frequency.","PeriodicalId":17004,"journal":{"name":"Journal of Science and Technology in Civil Engineering (STCE) - NUCE","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77273751","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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