scholarly journals The effect of lamina configuration and compaction pressure on mechanical properties of laminated gigantochloa apus composites

Author(s):  
Parlindungan Manik ◽  
Agus Suprihanto ◽  
Sri Nugroho ◽  
Sulardjaka Sulardjaka

This study aims to investigate the mechanical properties of bamboo apus (gigantochloa apus) as a natural reinforced composite material. Bamboo’s laminates of gigantochloa apus were used as reinforcement on the epoxy resin matrix. The parameters examined in this study are the configuration of lamina and compaction pressure. Laminate configuration varies in the number, thickness and direction of the lamina. Compaction pressures of 1.5 MPa, 2 MPa, and 2.5 MPa were used to fabricate the Laminated Bamboo Composites (LBCs). The stem of bamboo with a length of 400 mm was split to obtain bamboo lamina with a size of 400×20 mm. The thickness of bamboo lamina is varied between 1 mm, 1.5 mm, and 2 mm. The bamboo lamina is then preserved by watering it with a preservative solution in the form of 2.5 % sodium tetraborate solution and dried in an oven until the water content reaches 10 %. LBCs were made with a hand lay-up method. After the LBCs were molded, they were pressed with 3 variations of dies compaction 1.5 MPa, 2 MPa and 2.5 MPa. The tensile and bending tests were carried out on the LBCs. Tensile testing is performed in accordance with ASTM standard D3039 and the bending tests were conducted based on ASTM standard D7264. The results show that at each compaction pressure, the highest tensile and bending strength was achieved by LBCs with a thickness of 1 mm of bamboo lamina and 7 layers of bamboo laminates. The LBC with thinner bamboo lamina reinforcement and more layers has the highest tensile strength and bending strength, even it has a lower mass fraction. The LBCs with laminates oriented 0° exhibited greater tensile and bending strengths than the LBCs with laminates structured –45°/+45° and 0°/90°. The LBCs with the 0° laminates direction is matrix fracture followed by lamina fracture. In the 0°/90° direction, matrix fracture is followed by delamination in the 90° and 0° laminates direction. Delamination and lamina clefting were observed in LBCs with laminates oriented +45°/–45°.

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3158 ◽  
Author(s):  
Santiago Cano ◽  
Tanja Lube ◽  
Philipp Huber ◽  
Alberto Gallego ◽  
Juan Alfonso Naranjo ◽  
...  

The fused filament fabrication (FFF) of ceramics enables the additive manufacturing of components with complex geometries for many applications like tooling or prototyping. Nevertheless, due to the many factors involved in the process, it is difficult to separate the effect of the different parameters on the final properties of the FFF parts, which hinders the expansion of the technology. In this paper, the effect of the fill pattern used during FFF on the defects and the mechanical properties of zirconia components is evaluated. The zirconia-filled filaments were produced from scratch, characterized by different methods and used in the FFF of bending bars with infill orientations of 0°, ±45° and 90° with respect to the longest dimension of the specimens. Three-point bending tests were conducted on the specimens with the side in contact with the build platform under tensile loads. Next, the defects were identified with cuts in different sections. During the shaping by FFF, pores appeared inside the extruded roads due to binder degradation and or moisture evaporation. The changes in the fill pattern resulted in different types of porosity and defects in the first layer, with the latter leading to earlier fracture of the components. Due to these variations, the specimens with the 0° infill orientation had the lowest porosity and the highest bending strength, followed by the specimens with ±45° infill orientation and finally by those with 90° infill orientation.


2011 ◽  
Vol 399-401 ◽  
pp. 864-868
Author(s):  
Han Qiao Liu ◽  
Guo Xia Wei ◽  
Yin Liang ◽  
Jun Lan Yang

The glass-ceramics were made of arc-melting slag from incinerator fly ash mixed with glass cullet additive by sintering method. The effects of ball milling time and powder compaction pressure on the microstructure, physical and mechanical properties of the glass–ceramics were respectively investigated. Results showed that with milling time delaying, granularity of the parent glass evidently reduces, the major phases of glass–ceramics have no change but the diffraction peaks present intensive trend, the crystal sizes of glass–ceramics decrease, the properties such as volumetric densities, compressive strength, bending strength and toughness are improved, the appropriate milling time is 6h with fifty percent of the volume (d50 value) of 10.62μm. The physical and mechanical properties first increase and then decrease with compaction pressure increasing, and the optimal compaction pressure is 60MPa.


2019 ◽  
Vol 27 (1(133)) ◽  
pp. 37-44
Author(s):  
Marcin Barburski ◽  
Mariusz Urbaniak ◽  
Sanjeeb Kumar Samal

In this article, the mechanical properties of biaxial and triaxial woven aramid fabric and respective reinforced composites were investigated. Both fabrics had the same mass/m2. The first part of the experimental investigation was focused on the mechanical properties of different non-laminated aramid fabrics (biaxial and triaxial). The second part was concerned with the mechanical properties of composites made of a different combination of layers of fabric reinforced with an epoxy resin matrix in the order of biaxial+biaxial, trixial+triaxial and biaxial+triaxial. The composites were tested for tensile strength, flexural strength, strain and Young’s and flexural modulus. It can be seen from the results that the density and direction of the yarns are the most important parameters for determination of the strength of the fabric reinforced composite. The biaxial composite clearly showed better tensile strength, while the bi-tri axial order showed good flexural strength compared to the other composite combinations. These fabric reinforced composites have suitable applications in the areas of medical, protection and in the automotive industries.


Author(s):  
M. Dedeepya ◽  
T.Dharma Raju ◽  
T. Jayananda Kumar

Sustainable development is increasingly becoming a priority of governments and businered which is driven by growing environmental awareness. Much academic research explores new ways to create greener and environmentally friendlier materials for variety of aplications ranging from aeronautic, automotive and construction industry. The natural fibre reinforced composite has the advantage of being light weight, availability, strong, cheap, safe, ease of recycling, sustainability, renewability hermal and acoustic insulation, saving of fabrication energy and carbon dioxide neutrality. The composites are molded with unsaturated polyester resin matrix and reinforced with natural fibre. Five identical specimens are prepared for each fibre content. In this study, mechanical properties of composite such as tensile strength, tensile modulus were measured using universal testing machine. Guarded hot plate apparatus was used to measure the thermal conductivity of natural fibre typha angustifolia reinforced composite.. The results shows that mechanical properties, increased as fiber content increased. Thermal conductivity of composite is in the range of 0.168 w/m k to 0.187 w/m k and thermal conductivity decreased about 11.3% as fiber content increased. The newly developed composite material has lower thermal conductivity and is used as an insulating material to save energy.


Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2444 ◽  
Author(s):  
Shenggui Chen ◽  
Junzhong Yang ◽  
Yong-Guang Jia ◽  
Bingheng Lu ◽  
Li Ren

With the rapid application of light-curing 3D printing technology, the demand for high-performance polymer resins is increasing. Existing light-curable resins often have drawbacks limiting their clinical applications. This study aims to develop a new type of polymethyl methacrylate (PMMA) composite resins with enhanced mechanical properties, high antibacterial activities and excellent biocompatibilities. A series of reinforced composite resins were prepared by mechanically mixing PMMA with modified cellulose nanocrystals (CNCs), which were coated with polydopamine and decorated by silver nanoparticles (AgNPs) via Tollen reaction. The morphology of CNCs-Ag was observed by transmission electron microscopy and the formation of AgNPs on CNCs was confirmed by X-Ray photoelectron spectroscopy analyses. Functional groups in PMMA-CNCs-Ag composites were verified by Fourier Transform infrared spectroscopy (FTIR) spectroscopy. The mechanical assessment and scanning electron microscopy analysis suggested that the evenly distributed CNCs-AgNPs composite effectively improve mechanical properties of PMMA resin. Cytotoxicity assay and antibacterial activity tests indicated excellent biocompatibility and high antibacterial activities. Furthermore, PMMA with CNCs-AgNPs of 0.1 wt.% (PMMA-CNCs-AgNPs-0.1) possessed the most desirable mechanical properties owing to the homogeneous distribution of AgNPs throughout the resin matrix. This specific composite resin can be used as a functional dental restoration material with potential of other medical applications.


PRILOZI ◽  
2015 ◽  
Vol 36 (3) ◽  
pp. 138-149
Author(s):  
Vesna Jurukovska-Shotarovska ◽  
Biljana Kapusevska

Abstract Objectives: To make a comparative analysis of the mechanical properties between FRC and zirconium posts Methods: The patients with FRC and zirconium posts were divided in two groups with three subgroups, each of them composed of 10 samples. Subgroup I with 1.2 mm; Subgroup II with 1.35 mm and Subgroup III with 1.5 mm post diameter. The fracture force, bending and tensile strength of each group were measured with Shimadzu Universal Testing Machine. Results: The fracture force for the first group measured in the first, second and third subgroup was 34.80900N; 67.15390N; 46.53100N and for the second group, first, second and third subgroup was 34.80900N; 46.53100N; 67.15390N correspondingly. The bending strength for the first group measured in the first, second and third subgroup was 401.4420N; 444.6425N; 333.6828N and for the second group, first, second and third subgroup was 307.9352N; 289.1030N; 304.1649N correspondingly. The tensile strength for the first group measured in the first, second and third subgroup was 5.442267N; 4.350545N; 2.943465N and for the second group, first, second and third subgroup was 4.224141N; 3.751466N; 3.168756N correspondingly. Conclusions: The longest diameter of the posts significantly increases the resistance to fracture in relation to the two smaller diameters. The larger diameter, the higher values of the bending strength, as well as the lowest values of the tensile strength of the material contribute to improved mechanical properties of the fiber and zirconium posts.


Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5741
Author(s):  
Agnieszka Baziak ◽  
Kinga Pławecka ◽  
Izabela Hager ◽  
Arnaud Castel ◽  
Kinga Korniejenko

The aim of this paper is to analyze the influence of hybrid fiber reinforcement on the properties of a lightweight fly ash-based geopolymer. The matrix includes the ratio of fly ash and microspheres at 1:1. Carbon and steel fibers have been chosen due to their high mechanical properties as reinforcement. Short steel fibers (SFs) and/or carbon fibers (CFs) were used as reinforcement in the following proportions: 2.0% wt. CFs, 1.5% wt. CFs and 0.5% wt. SFs, 1.0% wt. CFs and 1.0% wt. SFs, 0.5% wt. CFs and 1.5% wt. SFs and 2.0% wt. SFs. Hybrid reinforcement of geopolymer composites was used to obtain optimal strength properties, i.e., compressive strength due to steel fiber and bending strength due to carbon fibers. Additionally, reference samples consisting of the geopolymer matrix material itself. After the production of geopolymer composites, their density was examined, and the structure (using scanning electron microscopy) and mechanical properties (i.e., bending and compressive strength) in relation to the type and amount of reinforcement. In addition, to determine the thermal insulation properties of the geopolymer matrix, its thermal conductivity coefficient was determined. The results show that the addition of fiber improved compressive and bending strength. The best compressive strength is obtained for a steel fiber-reinforced composite (2.0% wt.). The best bending strength is obtained for the hybrid reinforced composite: 1.5% wt. CFs and 0.5% wt. SFs. The geopolymer composite is characterized by low thermal conductivity (0.18–0.22 W/m ∙ K) at low density (0.89–0.93 g/cm3).


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