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Experimental evaluation and simulation of volumetric shrinkage and warpage on polymeric composite shortnatural fibers reinforced injection molded

Jonnathan D. SANTOS,Jorge I. FAJARDO,Alvaro R. CUJI,Jaime A. GARCÍA,Luis E. GARZÓN,Luis M. LÓPEZ

《机械工程前沿(英文)》 2015年 第10卷 第3期   页码 287-293 doi: 10.1007/s11465-015-0346-x

摘要:

A polymeric natural fiber-reinforced composite is developed by extrusion and injection molding process. The shrinkage and warpage of high-density polyethylene reinforced with short natural fibers of Guadua angustifolia Kunth are analyzed by experimental measurements and computer simulations. Autodesk Moldflow® and Solid Works® are employed to simulate both volumetric shrinkage and warpage of injected parts at different configurations: 0 wt.%, 20 wt.%, 30 wt.% and 40 wt.% reinforcing on shrinkage and warpage behavior of polymer composite. Become evident the restrictive effect of reinforcing on the volumetric shrinkage and warpage of injected parts. The results indicate that volumetric shrinkage of natural composite is reduced up to 58% with fiber increasing, whereas the warpage shows a reduction form 79% to 86% with major fiber content. These results suggest that it is a highly beneficial use of natural fibers to improve the assembly properties of polymeric natural fiber-reinforced composites.

关键词: biocomposite     natural fiber     shrinkage     simulation     warpage    

Computational simulation methods for fiber reinforced composites

Vladimír KOMPI, Zuzana MURINKOV, Sergey RJASANOW, Richards GRZIBOVSKIS, Qinghua QIN,

《结构与土木工程前沿(英文)》 2010年 第4卷 第3期   页码 396-401 doi: 10.1007/s11709-010-0079-1

摘要: Trefftz-finite element method (Trefftz-FEM), adaptive cross approximation BEM (ACA BEM) and continuous source function method (CSFM) are used for the simulation of composites reinforced by short fibers (CRSF) with the aim of showing the possibilities of reducing the problem of complicated and important interactions in such composite materials.

关键词: Trefftz-finite element method (Trefftz-FEM)     adaptive cross approximation BEM (ACA BEM)     method of continuous source functions     composite materials     short fibers    

Deflection behavior of a prestressed concrete beam reinforced with carbon fibers at elevated temperatures

Mohammed FARUQI, Mohammed Sheroz KHAN

《结构与土木工程前沿(英文)》 2019年 第13卷 第1期   页码 81-91 doi: 10.1007/s11709-018-0468-4

摘要: Fiber reinforced polymer(FRP) have unique advantages like high strength to weight ratio, excellent corrosion resistance, improving deformability and cost effectiveness. These advantages have gained wide acceptance in civil engineering applications. FRP tendons for prestressing applications are emerging as one of the most promising technologies in the civil engineering industry. However, the behavior of such members under the influence of elevated temperatures is still unknown. The knowledge and application of this could lead to a cost effective and practical considerations in fire safety design. Therefore, this study examines the deflection behavior of the carbon fiber reinforced polymer(CFRP) prestressed concrete beam at elevated temperatures. In this article, an analytical model is developed which integrates the temperature dependent changes of effective modulus of FRP in predicting the deflection behavior of CFRP prestressed concrete beams within the range of practical temperatures. This model is compared with a finite element mode (FEM) of a simply supported concrete beam prestressed with CFRP subjected to practical elevated temperatures. In addition, comparison is also made with an indirect reference to the real behavior of the material. The results of the model correlated reasonably with the finite element model and the real behavior. Finally, a practical application is provided.

关键词: FRP     CFRP     concrete     elevated temperatures     deflections     prestress    

Optimizing the compressive strength of concrete containing micro-silica, nano-silica, and polypropylene fibers

Fatemeh ZAHIRI, Hamid ESKANDARI-NADDAF

《结构与土木工程前沿(英文)》 2019年 第13卷 第4期   页码 821-830 doi: 10.1007/s11709-019-0518-6

摘要: Many studies have evaluated the effects of additives such as nano-silica (NS), micro-silica (MS) and polymer fibers on optimizing the mechanical properties of concrete, such as compressive strength. Nowadays, with progress in cement industry provides, it has become possible to produce cement type I with strength classes of 32.5, 42.5, and 52.5 MPa. On the one hand, the microstructure of cement has changed, and modified by NS, MS, and polymers; therefore it is very important to determine the optimal percentage of each additives for those CSCs. In this study, 12 mix designs containing different percentages of MS, NS, and polymer fibers in three cement strength classes(CSCs) (32.5, 42.5, and 52.5 MPa) were designed and constructed based on the mixture method. Results indicated the sensitivity of each CSCs can be different on the NS or MS in compressive strength of concrete. Consequently, strength classes have a significant effect on the amount of MS and NS in mix design of concrete. While, polymer fibers don’t have significant effect in compressive strength considering CSCs.

关键词: mixture method     compressive strength     nano-silica     micro-silica     polypropylene fibers    

Effect of fiber hybridization on energy absorption and synergy in concrete

Ahmadreza RAMEZANI, Mohammad Reza ESFAHANI

《结构与土木工程前沿(英文)》 2019年 第13卷 第6期   页码 1338-1349 doi: 10.1007/s17009-019-0558-2

摘要: In the present study, steel and polypropylene (PP) fibers have been utilized with the intent of obtaining hybrid fiber-reinforced concrete (HFRC) with desirable mechanical properties. An attempt has been made to scrutinize the properties of HFRC with the main concentration being on energy absorption characteristics of concrete and the efficacy of fiber hybridization in producing synergy. Accordingly, a total of 180 specimens, representing 20 different mixtures have been cast and evaluated through compressive, split tensile, and flexural tests. The relevant flexural toughness of the specimens was calculated using ASTM C1018, ASTM C1609, JSCE, and PCS methods, and the effectiveness of these methods was evaluated based on the experimental results. It was observed that steel fibers are more effective in the improvement of flexural toughness in the presence of PP fibers. Furthermore, synergy associated with the combination of fibers at different stages of deflection of the beam specimens was observed and analyzed.

关键词: hybrid fiber-reinforced concrete     synergy     toughness     steel fibers     polypropylene fibers    

The effect of carbon nanotubes and polypropylene fibers on bond of reinforcing bars in strain resilient

Souzana P. TASTANI,Maria S. KONSTA-GDOUTOS,Stavroula J. PANTAZOPOULOU,Victor BALOPOULOS

《结构与土木工程前沿(英文)》 2016年 第10卷 第2期   页码 214-223 doi: 10.1007/s11709-016-0332-3

摘要: Stress transfer between reinforcing bars and concrete is engaged through rib translation relative to concrete, and comprises longitudinal bond stresses and radial pressure. The radial pressure is equilibrated by hoop tension undertaken by the concrete cover. Owing to concrete’s poor tensile properties in terms of strength and deformability, the equilibrium is instantly released upon radial cracking of the cover along the anchorage with commensurate abrupt loss of the bond strength. Any improvement of the matrix tensile properties is expected to favorably affect bond in terms of strength, resilience to pullout slip, residual resistance and controlled slippage.The aim of this paper is to investigate the local bond of steel bars developed in adverse tensile stress conditions in the concrete cover. In the tests, the matrix comprises a novel, strain resilient cementitious composite (SRCC) reinforced with polypropylene fibers (PP) with the synergistic action of carbon nano-tubes (CNT). Local bond is developed over a short anchorage length occurring in the constant moment region of a four-point bending short beam. Parameters of investigation were the material structure (comprising a basic control mix, reinforced with CNTs and/or PP fibers) and the age of testing. Accompanying tests used to characterize the cementitious material were also conducted. The test results illustrate that all the benefits gained due to the synergy between PP fibers and CNTs in the matrix, namely the maintenance of the multi-cracking effect with time, the increased strength and deformability as well as the highly increased material toughness, were imparted in the recorded bond response. The local bond response curves thus obtained were marked by a resilient appearance exhibiting sustained strength up to large levels of controlled bar-slip; the elasto-plastic bond response envelope was a result of the confining synergistic effect of CNTs and the PP fibers, and it occurred even without bar yielding.

关键词: carbon nanotubes     strain resilient cementitious composite     polypropylene fibers     tensile bending     bond    

Recent developments in the application of oil palm fibers in cement composites

Emmanuel Owoichoechi MOMOH, Adelaja Israel OSOFERO

《结构与土木工程前沿(英文)》 2020年 第14卷 第1期   页码 94-108 doi: 10.1007/s11709-019-0576-9

摘要: Fibers obtained from different parts of the oil palm tree (Elaeis guineensis) have been under investigation for possible use in construction. Studies have been carried out investigating the engineering properties and possible applications of these fibers. However, the experimental methods employed and the values of mechanical and physical properties recorded by various authors are inconsistent. It has therefore become necessary to organize information which would be useful in the design of oil palm fiber cement composites and help researchers and engineers make informed decisions in further research and application. This review provides information about fibers from different parts of the oil palm, their properties, enhancement techniques, current and potential application in cement composites.

关键词: broom     cement composite     concrete     oil palm fiber     Natural fiber-concrete     sustainability    

environmental temperature and relative humidity on photocatalytic oxidation of toluene on activated carbon fibers

GUO Ting, BAI Zhipeng, WU Can, ZHU Tan

《环境科学与工程前沿(英文)》 2008年 第2卷 第2期   页码 224-229 doi: 10.1007/s11783-008-0039-3

摘要: TiO supported on active carbon fiber (TiO/ACF), an absorbable photocatalyst, is a new kind of material applied in air purification. In this paper, the influence of environmental temperature (T) and relative humidity (RH) on the gas-solid adsorption of toluene and the photocatalytic oxidation (PCO) efficiency of adsorbed toluene on TiO/ACF were studied, and then, the purification capability of TiO/ACF was estimated. PCO results showed that although the PCO efficiency increased under high RH and T levels, the amount of adsorption of toluene decreased. Moreover, quantitative analysis results of intermediates indicated that more environmental risk emerged when PCO of toluene was carried out at higher environmental T and RH levels because more toxic intermediates would be accumulated on the TiO/ACF. So, it is significant to control the environmental T and RH conditions in the application of the PCO technique. T = 25°C and RH = 30% is the optimal condition for purifying toluene in our experimental system.

关键词: application     gas-solid adsorption     technique     TiO/ACF     experimental    

Yuan-zhang Liu: a Short Biography

Anon

《工程管理前沿(英文)》 2014年 第1卷 第1期   页码 113-114 doi: 10.1530/J-FEM-2014016

Shou-rong Zhang: a Short Biography

Anon.

《工程管理前沿(英文)》 2014年 第1卷 第2期   页码 225-226 doi: 10.15302/J-FEM-2014030

推进我国产业用化纤材料的发展

季国标

《中国工程科学》 2003年 第5卷 第7期   页码 24-28

摘要:

回顾了10多年来产业用化纤材料的发展,提出现正处在持续增长期。参考世界发展情况,吸取其中有益的经验。结合我国实际,陈述了大类应用领域的前景以及在宏观管理上需要加强的有关问题。

关键词: 中国     产业用化纤材料     发展    

A hybrid Wavelet-CNN-LSTM deep learning model for short-term urban water demand forecasting

《环境科学与工程前沿(英文)》 2023年 第17卷 第2期 doi: 10.1007/s11783-023-1622-3

摘要:

● A novel deep learning framework for short-term water demand forecasting.

关键词: Short-term water demand forecasting     Long-short term memory neural network     Convolutional Neural Network     Wavelet multi-resolution analysis     Data-driven models    

Study on the crystal morphology and melting behavior of isothermally crystallized composites of short

Mingtao RUN, Hongzan SONG, Yanping HAO

《化学科学与工程前沿(英文)》 2009年 第3卷 第3期   页码 255-264 doi: 10.1007/s11705-009-0008-9

摘要: The spherulites of the short carbon fiber(SCF)/poly (trimethylene terephthalate) (PTT) composites formed in limited space at designed temperatures, and their melting behaviors were studied by the polarized optical microscopy, atomic force microscopy (AFM), and scanning electron microscopy (SEM), respectively. The results suggest that SCF content, isothermal crystallization temperatures, and the film thicknesses influence the crystal morphology of the composites. The dimension of the spherulites is decreased with increasing SCF content, but whether banded or nonbanded spherulites will form in the composites is not dependent on SCF content. However, the crystal morphology of the composites depends strongly on the temperature. When the isothermal crystallization temperatures increase from 180°C to 230°C, the crystal morphology of SCF/PTT composites continuously changes in the following order: nonbanded → banded → nonbanded spherulites. Discontinuous circle lines form in the film when the film thickness increases from 30 to 60 μm. Basing on the SEM observation, it is found that these circle lines are cracks formed due to the constriction difference of the different parts of the spherulites. These cracks are formed when the film is cooled from the isothermal crystallization temperature to the room temperature at a slow cooling rate; while they will disappear gradually at different temperatures in the heating process. The crack will appear/disappear first around the center of the spherulite when the film was cooled/heated. The nontwisted or slightly twisted lamellas will reorganize to form highly twisted lamellas inducing apparent banded texture of the spherulites.

关键词: poly(trimethylene terephthalate)     short carbon fiber     banded spherulites     crack    

Nonlinear finite element analysis of short-limbed wall

Zhi ZHANG, Qian GU, Shaomin PENG, Quanzhi CAI

《结构与土木工程前沿(英文)》 2009年 第3卷 第2期   页码 125-130 doi: 10.1007/s11709-009-0025-2

摘要: Combined with the actual project, this paper carries out a nonlinear finite element analysis on 2 groups, 6 short-limbed shear walls, through the finite element calculation software ANSYS. The stress-strain relation of the models, and the effects of the type of sections and the axial compression ratios on the models can be obtained, providing a reference for future design.

关键词: short-limbed wall (SLW)     nonlinear finite element     separate model     axial compression ratios    

Review of recent developments in cement composites reinforced with fibers and nanomaterials

Jianzhuang XIAO, Nv HAN, Yan LI, Zhongsen ZHANG, Surendra P. SHAH

《结构与土木工程前沿(英文)》 2021年 第15卷 第1期   页码 1-19 doi: 10.1007/s11709-021-0723-y

摘要: The quest for high-performance construction materials is led by the development and application of new reinforcement materials for cement composites. Concrete reinforcement with fibers has a long history. Nowadays, many new fibers associated with high performance and possessing eco-environmental characteristics, such as basalt fibers and plant fibers, have received much attention from researchers. In addition, nanomaterials are considered as a core material in the modification of cement composites, specifically in the enhancement of the strength and durability of composites. This paper provides an overview of the recent research progress on cement composites reinforced with fibers and nanomaterials. The influences of fibers and nanomaterials on the fresh and hardened properties of cement composites are summarized. Moreover, future trends in the application of these fibers or of nanomaterial-reinforced cement composites are proposed.

关键词: cement composites     fiber     nanomaterial     mechanical property     durability    

标题 作者 时间 类型 操作

Experimental evaluation and simulation of volumetric shrinkage and warpage on polymeric composite shortnatural fibers reinforced injection molded

Jonnathan D. SANTOS,Jorge I. FAJARDO,Alvaro R. CUJI,Jaime A. GARCÍA,Luis E. GARZÓN,Luis M. LÓPEZ

期刊论文

Computational simulation methods for fiber reinforced composites

Vladimír KOMPI, Zuzana MURINKOV, Sergey RJASANOW, Richards GRZIBOVSKIS, Qinghua QIN,

期刊论文

Deflection behavior of a prestressed concrete beam reinforced with carbon fibers at elevated temperatures

Mohammed FARUQI, Mohammed Sheroz KHAN

期刊论文

Optimizing the compressive strength of concrete containing micro-silica, nano-silica, and polypropylene fibers

Fatemeh ZAHIRI, Hamid ESKANDARI-NADDAF

期刊论文

Effect of fiber hybridization on energy absorption and synergy in concrete

Ahmadreza RAMEZANI, Mohammad Reza ESFAHANI

期刊论文

The effect of carbon nanotubes and polypropylene fibers on bond of reinforcing bars in strain resilient

Souzana P. TASTANI,Maria S. KONSTA-GDOUTOS,Stavroula J. PANTAZOPOULOU,Victor BALOPOULOS

期刊论文

Recent developments in the application of oil palm fibers in cement composites

Emmanuel Owoichoechi MOMOH, Adelaja Israel OSOFERO

期刊论文

environmental temperature and relative humidity on photocatalytic oxidation of toluene on activated carbon fibers

GUO Ting, BAI Zhipeng, WU Can, ZHU Tan

期刊论文

Yuan-zhang Liu: a Short Biography

Anon

期刊论文

Shou-rong Zhang: a Short Biography

Anon.

期刊论文

推进我国产业用化纤材料的发展

季国标

期刊论文

A hybrid Wavelet-CNN-LSTM deep learning model for short-term urban water demand forecasting

期刊论文

Study on the crystal morphology and melting behavior of isothermally crystallized composites of short

Mingtao RUN, Hongzan SONG, Yanping HAO

期刊论文

Nonlinear finite element analysis of short-limbed wall

Zhi ZHANG, Qian GU, Shaomin PENG, Quanzhi CAI

期刊论文

Review of recent developments in cement composites reinforced with fibers and nanomaterials

Jianzhuang XIAO, Nv HAN, Yan LI, Zhongsen ZHANG, Surendra P. SHAH

期刊论文