Predicting the Overall Properties of Composite Materials with Small-scale Inclusions or Cracks

Author(s):  
J. A. Hudson ◽  
L. Knopoff
Author(s):  
Bilim Atli-Veltin

In the small scale LNG infrastructure, composite materials are scarcely employed. Potentially, cost effective solutions for LNG applications could be developed thanks to the advantages of composite materials over metals such as weight savings, design flexibility and recyclability. The research presented in this paper focuses on the mechanical performance of fully recyclable, thermoplastic Polypropylene (PP) composite tapes at cryogenic LNG temperatures. Quasi-static tensile tests performed on [±45] laminates made of plain woven plies of PURE® show that at −196°C the behavior is bilinear with the failure strain of 6.5% and failure stress of 37 MPa. Such non-brittle failure behavior of PP is desirable for cryogenic applications. The other results presented in the paper contains [0/90] laminate results and the interlaminar shear strength characteristics at room and cryogenic temperatures.


Author(s):  
S V Knyazev ◽  
A A Usoltsev ◽  
A I Kutsenko ◽  
A A Kutsenko ◽  
S B Sokolov

Author(s):  
Daniel H. Morse ◽  
Arlyn J. Antolak ◽  
Bernice E. Mills

X-ray radiography has long been recognized as a valuable tool for detecting internal features and flaws. Recent developments in microfabrication and composite materials have extended inspection requirements to the resolution limits of conventional radiography. Our work has been directed toward pushing both detection and measurement capabilities to a smaller scale. Until recently, we have used conventional contact radiography, optimized to resolve small features. With the recent purchase of a nano-focus (sub-micron) x-ray source, we are now investigating projection radiography, phase contrast imaging and micro-computed tomography (μ-CT). Projection radiography produces a magnified image that is limited in spatial resolution mainly by the source size, not by film grain size or detector pixel size. Under certain conditions phase contrast can increase the ability to resolve small features such as cracks, especially in materials with low absorption contrast. Micro-computed tomography can provide three-dimensional measurements on a micron scale and has been shown to provide better sensitivity than simple radiographs. We have included applications of these techniques to small-scale measurements not easily made by mechanical or optical means. Examples include void detection in meso-scale nickel MEMS parts, measurement of edge profiles in thick gold lithography masks, and characterization of the distribution of phases in composite materials. Our work, so far, has been limited to film.


2019 ◽  
Vol 56 (4) ◽  
pp. 910-917
Author(s):  
Alexandru-Polifron Chirita ◽  
Paul-Petru Bere ◽  
Radu Iulian Rdoi ◽  
Liliana Dumitrescu

The article presents the technology and process, whereby a small-scale demonstration model and the real-scale prototype of vertical axis wind turbine blades are produced using rapid prototyping technology (3DP) and GFRP surface coatings, which help to improve the mechanical properties. In the end of the article the results of the production process and the advantages of combining these technologies are presented.


2021 ◽  
Vol 6 (2) ◽  
pp. 73
Author(s):  
Novi Laura Indrayani ◽  
R Hengki Rahmanto ◽  
Riri Sadiana

“Pemanfaatan material komposit pada saat ini semakin berkembang, seiring dengan meningkatnya penggunaan bahan tersebut yang semakin meluas mulai dari yang sederhana sampai sektor industri. Hal ini dikarenakan karakteristik material komposit mempunyai banyak kelebihan dibandingkan dengan jenis bahan lain yaitu  ringan, kuat, tidak terpengaruh korosi dan mampu bersaing dengan logam, dengan tidak kehilangan karakteristik dan kekuatan mekanisnya. Penelitian ini bertujuan untuk mengetahui pengaruh variasi waktu sintering dan komposisi terhadap ketangguhan impak dan kekerasan komposit Eceng Gondok-PVC-LDPE. Bahan yang digunakan merupakan tanaman gulma dan limbah plastik. Proses pembuatan spesimen dilakukan dengan metode pressured sintering, yaitu dengan cara pembuatan serbuk, dan di screening 60 mesh. Selanjutnya serbuk di mixing dengan variasi komposisi perbandingan K1: EG 50%, PVC 10%, LDPE 40%; K2: EG 55%, PVC 10%, LDPE 35%; K3: EG 60%, PVC 10%, LDPE 30%; K4: EG 65%, PVC 10%, LDPE 25% dan K5: EG 70%, PVC 10%, LDPE 20% dan dikompaksi dengan tekanan 1,013 bar. Selanjutnya di sintering dengan temperatur 1800C. Pada penilitian ini variasi waktu sintering yaitu; 5 menit, 8 menit, 10 menit, 13 menit dan 15 menit. Sifat mekanik dilihat dari nilai kekerasan dan impak dengan menggunakan standar ISO 2039-1:2001, ISO 179-1:2010. Selain itu menganalisis morfologi dengan Scanning Electron Microscope (SEM). Pengujian untuk sifat kimia dilihat dengan analisis morfologi SEM. Berdasarkan hasil pengujian sifat mekanik didapatkan nilai kekerasan tertinggi dimiliki oleh komposit K2 sebesar 22.30 MPa dan 2.1 kJ/m2 untuk nilai impak.” Kata kunci: eceng gondok, komposit, LDPE, pressured sintering, PVC. Abstract“The utilization of composite materials nowadays is currently growing, along with the increasing use of these materials, which are expanding ranging from the small scale to the industrial sector. This is because the characteristics of composite materials have many advantages compared to other types of materials i.e. light, strong, not affected by corrosion and able to compete with metals without losing their mechanical characteristics and strength. This research aims to determine the effect of variations in sintering time and it’s composition against impact toughness and hardness of the Water Hyacinth-PVC-LDPE composite. The materials used are weeds and plastic waste. The process of specimen fabrication was performed by using pressured sintering method, i.e. by making it into powder and were screening by using screen 60 mesh. Furthermore, the powder were mixed with the variation of the composition K1: EG 50%, PVC 10%, LDPE 40%; K2: EG 55%, PVC 10%, LDPE 35%; K3: EG 60%, PVC 10%, LDPE 30%; K4: EG 65%, PVC 10%, LDPE 25% dan K5: EG 70%, PVC 10%, LDPE 20% and compacted with a pressure of 1,1013 bar. After that is sintering with temperature 180oC. In this research the sintering time variations is 5 minute, 8 minute, 10 minute, 13 minute and 15 minute. Mechanical properties if were seen from the hardness and impact values by using a standard ISO 2039-1:2001, ISO 179-1:2010. In additions to analyze the morphology by using a Scanning Electron Microscope (SEM). Tests for chemical properties can be seen with the morphological analysis of SEM. Based on the testing results, the mechanical properties obtained the highest hardness value owned by a composite K2 by 22.30 MPa and 2.1 kJ/m2 for the value of the impact.” Kata kunci:water hyacinth, composite, LDPE, pressured sintering, PVC.


1992 ◽  
Vol 28 (12) ◽  
pp. 794-800 ◽  
Author(s):  
S. D. Akbarov ◽  
A. N. Guz' ◽  
A. D. Zamanov

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