检索结果-南通市图书馆

Thermoviscoelastic Analysis of Stress in Composite Structures Micro-to-Structural Approach

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Transactions of Nanjing University of Aeronautics and Astronautics 2014年第2期31卷 191-194页

作者： Liri Shemesh Jacob Aboudi Rami Eliasi David Livshits Department of Mechanical Engineering Tel Aviv University Israel Israel Military Industries Ltd. Israel

Manufacturing of composite materials is usually accompanied with residual stresses.These stresses should be evaluated and assessed.To this end,a micromechanical model for periodic material whose temperature dependent constituents behave as thermorheologically complex materials(TCM)has been developed.This model,referred as the high fidelity generalized method of cells(HFGMC),takes into account the detailed interaction between the fiber and resin,their volume ratios,the fibers distribution and their waviness.This model is linked,in conjunction with a special UMAT subroutine,to the ABAQUS finite element code for prediction of the response of thermoviscoelastic composite structures during cool down process.The present investigation shows the effect of the cool down rate on the residual stress developed in the composite cylindrical structures.

关键词： cool down thermorheologically complex materials(TCM) epoxy high fidelity generalized method of cells(HFGMC) finite element method(FEM)

Rapid Tooling Technique Based on Stereolithograph Prototype

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Donghua University(English Edition) 2001年第2期18卷 105-107页

作者：丁浩狄平顾伟生朱世根 Dept. of Mech. Eng. Dong Hua Univ. Shanghai 200051 China

Rapid tooling technique based on the sterelithograph prototype is investigated. The epoxy tooling technological process was elucidated. It is analyzed in detail that the epoxy resin formula is easy to cast, curing process, and release agents. The transitional plaster model is also proposed. The mold to encrust mutual.inductors with epoxy and mold to inject plastic soapboxes was made with the technique The tooling needs very little time and cost, for the process is only to achieve the nice replica of the prototype. It is benefit for the trial and small batch of production.

关键词： stereolithography prototype, epoxy resin, tooling,transitional mold

Tensile Properties of Weft Knitted Fabric Reinforced Composites

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Donghua University(English Edition) 2001年第1期18卷 97-100页

作者： Long Hairu(龙海如) College of Textiles Dong Hua University Shanghai 200051

Seven kinds of weft knitted fabrics from glass fiber yarns were used as reinforcement to make fabric/epoxy composite laminates. Tensile tests were carried out to examine and compare the mechanical properties in course and wale direction of these composites. On the basis of experimental results, attempts have been made to analyze some main factors influencing stress-strain curve, ultimate tensile strength and initial elastic modulus of specimens.

关键词： weft knitted fabric, glass fiber/ epoxy composite,tensile properties.

The Effect of Curative Concentration on Thermal and Mechanical Properties of Flexible epoxy Coated Jute Fabric Reinforced Polyamide 6 Composites

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Open Journal of Composite Materials 2012年第4期2卷 133-138页

作者： Smith Thitithanasarn Kazushi Yamada Umaru S. Ishiaku Hiroyuki Hamada Department of Advanced Fibro-Science Kyoto Institute of Technology Kyoto Japan Department of Textile Science and Technology Faculty of Science Ahmadu Bello University Zaria Nigeria

Many researchers have shown interest in the reinforcement of commodity thermoplastic with natural fibers. However, the drawback of natural fibers is their low thermal processing temperatures, that border around 200℃. In this investigation, we tried to improve the thermal stability of natural fibers with the use of flexible epoxy surface coating that could facilitate processing with engineering thermoplastics. Jute fabric and Polyamide 6 (PA6) composites were prepared by compression molding. The thermal decomposition characteristics of the jute fabric were evaluated by using thermo gravimetric analysis (TGA). Mechanical analysis was conducted to evaluate tensile test and three point bending test of composite. It was found that thermal degradation resistance of jute fabric was improved by coating with flexible epoxy resin. Moreover, the flexural modulus improved with increasing curative concentration. The interfacial interaction between the epoxy and PA6 was clearly indicated by the photo micrographs of the polished cross sections of the coated and uncoated jute fabric/PA6 composites.

关键词： Natural Fiber (Jute) Polyamine 6 Flexible epoxy Composites Thermal Degradation Mechanical Properties

Dielectric Properties and a.c. Conductivity of epoxy/Alumina Silicate NGK Composites

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Chemical Engineering and Science 2015年第3期5卷 282-289页

作者： Waleed A. Hussain Abdullah A. Hussein Jabar M. Khalaf Ali H. Al-Mowali Abdullwahab A. Sultan Department of Physics College of Education for Pure Science Basrah University Basrah Iraq Department of Material Science Polymer Research Centre University of Basrah Basrah Iraq Department of Chemistry College of Science University of Basrah Basrah Iraq Southern Technical College Basrah Iraq

Alumina silicate powder which is extracted from the obsolete spark plug NGK (insulator part as a filler) has been used to produce epoxy/alumina silicate composite. The dielectric behavior of the composite materials (epoxy resin-alumina silicate NGK) is analyzed as a function of the filler content, temperature and frequency. AC conductivity and impedance are also studied. The results show that the permittivity, dielectric loss and loss tangent for all composites increase with increasing alumina silicate NGK filler content.

关键词： Polymer-Matrix Composites Dielectric Properties epoxy Alumina Silicate

Re-Assembly of Archaeological Massive Limestones Using epoxy Resin Modified with Nanomaterials—Part 1: Experimental

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Green and Sustainable Chemistry 2020年第1期10卷 24-38页

作者： Mohammad A. Aldosari Sawsan S. Darwish Mahmoud A. Adam Nagib A. Elmarzugi Sayed M. Ahmed National Nanotechnology Research Center King Abdulalziz City for Science and Technology (KACST) Riyadh KSA Department of Conservation Faculty of Archaeology Cairo University Giza Egypt Faculty of Pharmacy Tripoli University and National Nanotechnology Project Biotechnology Research Center LARST Tripoli Libya Ministry of Antiquities The Grand Egyptian Museum Giza Egypt

Massive limestones were used in construction of ancient Egyptian tombs, temples, obelisks and other sculptures. These stones are always exposed to physico-mechanical deterioration and destructive forces, leading to partial or total collapse. The task of reassembling this type of artifacts represents a big challenge for the conservators. Recently, the researchers are turning to new technologies to improve the properties of traditional adhesive materials and techniques used in re-assembly of broken massive stones. The epoxy resins are used extensively in stone conservation and re-assembly of broken stones because of their outstanding mechanical properties. The adding of nanoparticles to polymeric adhesives at low percentages may lead to substantial improvements of their mechanical performances in structural joints and massive objects. The aim of this study is to evaluate the effectiveness of montmorillonite clay, calcium carbonate, and silicon dioxide nanoparticles for enhancing the performances of epoxy adhesives used in re-assembly of archaeological massive limestones. Scanning electron microscopy (SEM) was employed in order to investigate the morphology of the prepared nanocomposites, and the distribution of nanoparticles inside the composites. Artificial aging, tensile, compressive, and elongation strength tests were used to evaluate the efficiency of epoxy-nanocomposites. The results showed that the epoxy-clay nanocomposites exhibited superior tensile, compressive, and elongation strength, in addition to improving the mechanical properties of stone joints.

关键词： epoxy Resins Nanocomposites Re-Assembly Massive Limestones Mechanical Properties

Processing and Characterization of PMMA Nanofiber Reinforced epoxy Composites

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Nano Science and Engineering 2016年第2期6卷 58-63页

作者： Salwan Al-Assafi Nils de Bruijn Ahmed M. Al-Jumaily Institute of Biomedical Technologies Auckland University of Technology Auckland New Zealand Academie for Technology Health and Environment Avans University of Applied Sciences Breda Netherlands

Growing demand for high-performance materials is driving the development of composites with nano material reinforcement. The use of nano reinforcement can provide a distinct advantage due to high surface area of the material. There are still many challenges in achieving the full potential of nanocomposites. In this paper, we investigate the performance of epoxy nanocomposites reinforced with short polymethyl methacrylate (PMMA) nanofibers. PMMA nanofibers were chopped and mixed with the epoxy resin and then the mixture was poured into a mould. Samples were cut to an appropriate size after cure and mechanical testing was carried out. Tensile and flexural strength and modulus were evaluated for samples with various fiber volume fractions to determine changes in mechanical performance. Also Scanning Electron Microscopy was utilized to investigate fracture surface and fiber-matrix interface. Results indicated that mechanical performance dropped as volume fraction of fibers increased, namely poor fiber-matrix adhesion and presence of porosity resulted in deterioration in strength and modulus. Further research is required to develop fiber coating system to enhance performance of the nanocomposite by improving fiber-matrix adhesion and fiber wet-out.

关键词： Nanocomposite Nanofiber epoxy Electrospinning PMMA Polymer Composites

Kinetic Study of Resin-Curing on Carbon Fiber/epoxy Resin Composites by Microwave Irradiation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Composite Materials 2014年第2期4卷 85-96页

作者： Daisuke Shimamoto Yusuke Imai, Yuji Hotta Advanced Manufacturing Research Institute National Institute of Advanced Industrial Science and Technology (AIST) Nagoya Japan

Microwave processing has great potential for improving composite manufacturing such as reduction of curing time, energy requirements and operational costs. In this paper, the effects of microwave irradiation for resin-curing of carbon fiber/epoxy resin composite that was composed of discontinuous carbon fibers of 130 μm or 3 mm were investigated. The mechanical properties of carbon fiber/epoxy resin composite cured by microwave irradiation for 20 min at 120°C were similar to ones of the sample prepared by conventional oven for 180 min at 120°C. Microwavecured carbon fiber/epoxy resin composite had higher glass transition temperature than the one prepared by conventional oven. The relation between curing time and flexural modulus indicated that the curing velocity of microwave-irradiated carbon fiber/epoxy resin composite was 9 times faster than the one prepared by conventional oven. Furthermore, activation energies for resincuring reaction on microwave and conventional-cured carbon fiber/epoxy resin composite were estimated. The resin-curing reaction in carbon fiber/epoxy resin composite was promoted by microwave irradiation.

关键词： Activation Energy Resin-Curing Microwave Irradiation epoxy Resin Carbon Fiber

Mechanical Properties of epoxy Composite Materials Produced with Different Ceramic Powders

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science and Chemical Engineering 2019年第12期7卷 1-8页

作者： Yelda Akcin Ergün Department of Metallurgical and Material Engineering Faculty of TechnologyAfyon Kocatepe UniversityAfyonkarahisarTurkey

In this study, production and mechanical properties of polymer composite materials obtained by using Al2O3, SiO2, MgO and TiO2 hard ceramic fillers were studied. epoxy resin was used as the matrix material, and four different ceramic powders were mechanically mixed into the resin at 3% and 5% as reinforcement. The mechanical properties of the polymer composite materials were then characterized. For this purpose, flexural modulus and flexural strength of composite materials were determined by using three point bending test and impact toughness of the materials were determined by Charpy impact test. In addition, the hardness values of the samples were determined by Shore D hardness test.

关键词： Polymer Composite epoxy Ceramic Powders Mechanical Properties