Study of mode II interlaminar fracture toughness of laminated composites of glass and jute fibres in epoxy for structural applications

Composites are being used in the place of metals in many industries as they have a lower density and are cheaper than metals. In aerospace industries there is requirement for light weight together with strength, and reinforced fibre composites are superior in some critical properties compared with metals. In this study, laminated composites were fabricated with woven E-glass and jute fibres in an epoxy matrix by a hand layup method. The samples were prepared as per the relevant the America Society for Testing ad Materials (ASTM) standard and tested for mode II interlaminar fracture toughness to investigate delamination resistance. Mode II interlaminar fracture toughness was evaluated by an end-notched flexure test using three-point bending. The fracture toughness G IIC was calculated for a curing temperature range from 40 °C to 70 °C at intervals of 5 °C for different sets of laminated composites. The investigations revealed that when the curing temperature of laminated composites was increased from 40 °C to 70 °C, the interlaminar fracture toughness G IIC was increased in neat woven E-glass laminated composites, decreased in neat jute laminated composites, significantly increased in laminated composites with woven E-glass fibres in compression and jute fibres in tension and slightly increased when woven E-glass fibres were kept in tension and jute fibres in compression.

Spinning of Endless Bioactive Silicate Glass Fibres for Fibre Reinforcement Applications

Bioactive glasses have been used for many years in the human body as bone substitute. Since bioactive glasses are not readily available in the form of endless thin fibres with diameters below 20 µm, their use is limited to mainly non-load-bearing applications in the form of particles or granules. In this study, the spinnability of four bioactive silicate glasses was evaluated in terms of crystallisation behaviour, characteristic processing temperatures and viscosity determined by thermal analysis. The glass melts were drawn into fibres and their mechanical strength was measured by single fibre tensile tests before and after the surface treatment with different silanes. The degradation of the bioactive glasses was observed in simulated body fluid and pure water by recording the changes of the pH value and the ion concentration by inductively coupled plasma optical emission spectrometry; further, the glass degradation process was monitored by scanning electron microscopy. Additionally, first in vitro experiments using murine pre-osteoblast cell line MC3T3E1 were carried out in order to evaluate the interaction with the glass fibre surface. The results achieved in this work show up the potential of the manufacturing of endless bioactive glass fibres with appropriate mechanical strength to be applied as reinforcing fibres in new innovative medical implants.

Mechanical Properties of novel hardened cement paste reinforced with Multi-Walled Carbon Nano-Tubes (MWCNTs) and Glass Fibers Nano material

To improve the mechanical and durability properties of ordinary Portland cement (OPC) mortar and paste, the incorporation of multi walled Carbon nanotubes (MWCNTs) and their dispersion procedures, functionalization, and ultra sonication have been intensively implemented. Most of the studies showed significant enhancements in the mechanical properties of OPC mortar or paste; however, others showed impairments. The recent studies regarding the implementation of MWCNTs and Glass Fibres on the mechanical properties of OPC paste and mortar were reviewed and these properties include compressive, tensile, flexural strengths, and elastic modulus. A statistical study was conducted to evaluate the mechanical properties of concrete by dispersion of MWCNT’s and Glass Fibres in the cement paste. In these composites, the percentage of MWCNTs was fixed at 0.75% by weight of cement, while the percentage of Glass Fibers was fixed at 0.25% by weight of cement. The samples were cured in tap water for 28 days at 25 + 2?C.Composite specimens were tested for compression and flexure in order to evaluate their mechanical properties such as compressive strength, flexural strength, toughness and ductility and compared with the results of plain cement control beams. The maximum deflection was found to be 0.5mm with a maximum load of 500N. The flexural strength was observed to be 1250.50 N/mm2 as per ASTM D 790 which is 20% more than the flexural strength obtained with Plain Cement+MWCNT’s and 60 to 70% more than that obtained with Plain Cement + Glass Fibres. The flexural modulus as per deflection criteria is 535.94 N/mm2 which is 10 to 20% more than that obtained of Plain Cement+MWCNT’s and Plain Cement+ Glass Fibres. The compressive strength of Plain Cement+0.75% MWCNT’s+0.25% Glass fibres was found to be 65 N/mm2 which is greater than Plain cement and Plain cement+MWCNT’s. Surface morphology by Scanning Electron microscopy of the specimens infers the clustering of glass fibres and demonstr

Assessing Fracture Toughness and Impact Strength of PMMA Reinforced with Nano-Particles and Fibre as Advanced Denture Base Materials

Statement of Problem: Polymethyl methacrylate (PMMA) denture resins commonly fracture as a result of the denture being dropped or when in use due to heavy occlusal forces. Purpose: To investigate the effects of E-glass fibre, ZrO2 and TiO2 nanoparticles at different concentrations on the fracture toughness and impact strength of PMMA denture base. Materials and Methods: To evaluate fracture toughness (dimensions: 40 × 8 × 4 mm3; n = 10/group) and impact strength (dimensions: 80 × 10 × 4 mm3; n = 12/group), 286 rectangular tested specimens were prepared and divided into four groups. Group C consisted of the PMMA specimens without any filler (control group), while the specimens in the remaining three groups varied according to the concentration of three filler materials by weight of PMMA resin: 1.5%, 3%, 5%, and 7%. Three-point bending and Charpy impact tests were conducted to measure the fracture toughness and impact strength respectively. Scanning Electron Microscope (SEM) was utilised to examine the fractured surfaces of the specimens after the fracture toughness test. One-way analysis of variance (ANOVA) followed by Tukey post-hoc tests were employed to analyse the results at a p ≤ 0.05 significance level. Results: Fracture toughness of groups with 1.5 and 3 wt.% ZrO2, 1.5 wt.% TiO2, and all E-glass fibre concentrations were significantly higher (p < 0.05) than the control group. The samples reinforced with 3 wt.% ZrO2 exhibited the highest fracture toughness. Those reinforced with a 3 wt.%, 5 wt.%, and 7 wt.% of E-glass fibres had a significantly (p < 0.05) higher impact strength than the specimens in the control group. The heat-cured PMMA modified with either ZrO2 or TiO2 nanoparticles did not exhibit a statistically significant difference in impact strength (p > 0.05) in comparison to the control group. Conclusions: 1.5 wt.%, 3 wt.% of ZrO2; 1.5 wt.% ratios of TiO2; and 1.5 wt.%, 3 wt.%, 5 wt.%, and 7 wt.% of E-glass fibre can effectively enhance the fracture toughness of PMMA. The inclusion of E-glass fibres does significantly improve impact strength, while ZrO2 or TiO2 nanoparticles did not.