Comparative Analysis Of Mechanical Properties Of Rubber-Kenaf-Wire-Cotton Lamination On Epoxy-Carbon-Ramie Composite

The use of fiber has been widely researched but the use of several fibers as reinforcement does not necessarily result in optimal mechanical properties. This study aimed to determine the tensile strength and impact strength of composite materials using an epoxy matrix with the addition of rubber variations to increase the ductility of the matrix. Meanwhile, the fibers used for reinforcement are carbon fiber and ramie. In this study, the reinforcement added a variety of kenaf fiber, wire and cotton. This was to compare the role of kenaf fiber, wire and cotton in improving the mechanical properties of composite materials. The percentage of rubber volume fraction added to the epoxy is 30%, 40% and 50%.The highest tensile test results were shown in the 30% epoxy rubber-carbon fiber-ramie fiber-kenaf specimen which was 10.67 Kgf / mm2, and the lowest result was the epoxy 50% rubber-carbon fiber-ramie-wire specimen, which was 5.752 kgf / mm2. The fracture analysis of the tensile test showed that the fracture area is formed by debonding phenomena between fibers and matrices.The highest impact strength was found in the 50% epoxy rubber-carbon fiber-ramie-wire specimen, which was 0.039 kgf / mm2. Meanwhile, the lowest impact strength was found in the 40% epoxy rubber-carbon fiber-ramie fiber-cotton specimen, which was 0.030 kgf/ mm2. In general, the trend of impact test data shows that as the percentage volume fraction of rubber increases, the impact strength of the composite material increases.Based on the test analysis, it was concluded that increasing the percentage of rubber will increase the impact strength of the woven wire reinforcement. However, the impact strength is inversely proportional to kenaf fiber reinforcement, where the addition of the percentage of rubber will reduce the impact strength. This showed that the mechanical properties were not always influenced by the percentage of rubber but were very dependent on the type of fiber. This was also shown in the results of the tensile strength test. In general, it was known that the adhesion between fiber and matrix laminates affected the mechanical properties in addition to the strength of the reinforcement.

Experimental identification of the degree of deformation of a wire subjected to bending

This study provides experimental verification of analytical results on maximum strain ?max in elements fabricated by bending a stainless steel wire around a cylinder with given dimensions. The method of measuring the thermal electromotive force (TEMF) of a thermocouple formed by joining the deformed metal specimen to a copper (Cu) conductor showed an increase in the thermal electromotive force coefficient (TEMFC) during heating with increasing degree of plastic deformation. For known values of plastic deformation produced by straining X5CrNi1810 stainless steel wire specimens of ?2.8 mm diameter, the TEMF was determined as a function of the extent of deformation of the thermocouple consisting of the deformed steel wire specimen and the copper conductor. Based on the correlation (calibration curve), it was shown that the relative strain of the element fabricated by bending the same wire (made of X5CrNi1810 stainless steel, ?2.8 mm in diameter) around the cylinder of ?10 mm diameter is 23.8 %.

Double-tilt FIM specimen holder for JEOL 200CX

It has long been recognized that combined TEM and FIM analyses provide a powerful analytical combination. Special holders that will accept needle shaped FIM specimens have been built and used by several investigators. However, full advantage of the TEM could not be taken because previous holders have been capable of single axis rotation only--about the specimen direction. Diffraction contrast studies were then limited to a few chance orientations and many analytical questions remained unresolved. A second othogonal tilt axis, of even modest range thus enhances the possibilities considerably. The double tilt holder described here covers the angular range ± 20° on the orthogonal or Y-axis. In addition, the wire specimen can be remounted at any rotated position so that the experimentally accessible range is ± 180°. This combined angular range is sufficient for most diffraction contrast experiments. More to the point, it permits the attainment of a number of two-beam conditions. The JEOL 200CX used here also has a combined EDS and ELS capacity and the FIM is configured as an imaging atom probe (IAP).

Zur Technik des Abschreckens von Metallen in Helium II

A small wire specimen can be heated to high temperatures in liquid Helium II by electric current, and quenched by switching off the current. Experimental details about quenching experiments on tungsten wires (0.030 mm Ø) are given. The quenching speed at 2500 °K amounts to about 3·104°K/sec. The temperature, as function of time, was recorded oscillographically during cooling down. This technique is particularly qualified for refractory metals.