scholarly journals Material Characterization Results for a Selected Graphite Fiber/Epoxy Composite

Author(s):  
G. E. Molter ◽  
E. A. Rothman

Static and dynamic strength tests and modulus data are reported for a uniaxial graphite yarn reinformcement impregnated with an epoxy matrix by the vacuum injection molding technique. All testing was done at room temperature. An inherent tendency to fracture in inter-laminar shear was observed.

2008 ◽  
Vol 19 (4) ◽  
pp. 348-353 ◽  
Author(s):  
Rafael Leonardo Xediek Consant ◽  
Erica Brenoe Vieira ◽  
Marcelo Ferraz Mesquita ◽  
Wilson Batista Mendes ◽  
João Neudenir Arioli-Filho

This study evaluated the effect of microwave energy on the hardness, impact strength and flexural strength of the Clássico, Onda-Cryl and QC-20 acrylic resins. Aluminum die were embedded in metallic or plastic flasks with type III dental stone, in accordance with the traditional packing technique. A mixing powder/liquid ratio was used according to the manufacturer's instructions. After polymerization in water batch at 74ºC for 9 h, boiling water for 20 min or microwave energy at 900 W for 10 min, the specimens were deflasked after flask cooling at room temperature, and submitted to finishing. Specimens non-disinfected and disinfected by microwave irradiation were submitted to hardness, impact and flexural strength tests. Each specimen was immersed in distilled water and disinfected in a microwave oven calibrated to 650 W for 3 min. Knoop hardness test was performed with 25 g load for 10 s, impact test was carried out using the Charpy system with 40 kpcm, and 3-point bending test with a crosshead speed of 0.5 mm/min until fracture. Data were submitted to statistical analysis by ANOVA and Tukey's test (?=0.05). Disinfection by microwave energy decreased the hardness of Clássico and Onda-Cryl acrylic resins, but no effect was observed on the impact and flexural strength of all tested resins.


2012 ◽  
Vol 602-604 ◽  
pp. 627-630 ◽  
Author(s):  
Kyu Sik Kim ◽  
Kee Ahn Lee ◽  
Jong Ha Kim ◽  
Si Woo Park ◽  
Kyu Sang Cho

Inconel 713C alloy was tried to manufacture by using MIM(Metal Injection Molding) process. The high-temperature mechanical properties of MIMed Inconel 713C were also investigated. Processing defects such as pores and binders could be observed near the surface. Tensile tests were conducted from room temperature to 900°C. The result of tensile tests showed that this alloy had similar or somewhat higher strengths (YS: 734 MPa, UTS: 968 MPa, elongation: 7.16 % at room temperature) from RT to 700°C than those of conventional Inconel 713C alloys. Above 800°C, however, ultimate tensile strength decreased rapidly with increasing temperature (lower than casted Inconel 713C). Based on the observation of fractography, initial crack was found to have started near the surface defects and propagated rapidly. The superior mechanical properties of MIMed Inconel 713C could be obtained by optimizing the MIM process parameters.


Author(s):  
Antonio Piccininni ◽  
Andrea Lo Franco ◽  
Gianfranco Palumbo

Abstract A warm forming process is designed for AA5754 to overcome low room temperature formability. The solution includes increased working temperature and is demonstrated with a railway vehicle component. A Finite Element (FE) based methodology was adopted to design the process taking into account also the starting condition of the alloy. In fact, the component's dent resistance can be enhanced if the yield point is increased accordingly: the stamping process was thus designed considering the blank in both the H111 (annealed and slightly hardened) and H32 (strain-hardened and stabilized) conditions that were preliminarily characterized. Tensile and formability tests were carried out at different temperature and strain rate levels, thus providing the data to be implemented within the FE model (Abaqus/CAE): the stamping was at first simulated at room temperature to evaluate the blank critical regions. Subsequently, the warm forming process was designed by means of an uncoupled thermo-mechanical approach. Thermal simulations were run to properly design the heating strategy and achieve an optimal temperature distribution over the blank deformation zone (according to the results of the material characterization). Such a distribution was then imported as a boundary condition into the mechanical step (Abaqus/Explicit) to determine the optimal process parameters and obtain a sound component (strain severity was monitored implementing an FLD-based damage criterion). The simulation model was validated experimentally with stamping trials to fabricate a sound component using the optimized heating strategy and punch stroke profile.


2015 ◽  
Vol 76 (10) ◽  
Author(s):  
Khai Wei Chua ◽  
Mohd Fadzli Bin Abdollah ◽  
Noor Ayuma Mat Tahir ◽  
Hilmi Amiruddin

This study investigates the effect of normal load on the frictional properties of palm kernel activated carbon-epoxy (PKAC-E) composite. The PKAC-E composite specimen was fabricated by hot compression molding method. The dry sliding test was performed by using a pin-on-disc tribometer at various normal loads, range from 5 – 100N. The sliding speed and distance were constant. All tests were performed at room temperature. It was found that the coefficient of friction decreases with normal load, though at 60N, friction coefficient increases slightly and remains almost invariant at about 0.04 with normal load. The main conclusion of this study is that PKAC-E composite has a potential for tribological material application but only limited at low normal load under unlubricated conditions.


2014 ◽  
Vol 775-776 ◽  
pp. 284-289 ◽  
Author(s):  
Sergio Neves Monteiro ◽  
Frederico Muylaert Margem ◽  
Wellington Pereira Inácio ◽  
Artur Camposo Pereira ◽  
Michel Picanço Oliveira

The tensile properties of DGEBA/TETA epoxy matrix composites reinforced with different amounts of sisal fibers were evaluated. Composites reinforce with up to 30% in volume of long, continuous and aligned sisal fibers were room temperature tested in an Instron machine. The fracture was analyzed by SEM. The results showed significant changes in the mechanical properties with the amount of sisal fibers. These mechanical properties were compared with other bend-tested composites results. The fracture analysis revealed a weak fiber/matrix interface, which could be responsible for the performance of some properties.


Sign in / Sign up

Export Citation Format

Share Document