Improvement of Gravelly Silty Sand Reinforced with Biaxial Bamboo Geogrid

In this paper, performance of gravelly silty sand soil reinforced with geogrid are present and analyzed to improve the carrying capacity. For this, the geogrid was elaborated with a renewable material like bamboo with the same dimensions of polymer geogrids biaxial. This type of soil can be used for the construction of the sub-base and base of a pavement. California Bearing Ratio (CBR) tests was carried out to obtain the bearing capacity of the silty sand soil with and without bamboo geogrid. In addition, laboratory tests were carried out to obtain the mechanical properties of the bamboo. When comparing CBR results, an improvement in the bearing capacity was evidenced with the use of bamboo geogrid with a 20% increase in the carrying capacity. Finally, maximum tensile and bending strength of bamboo were 2000 kgf/cm2 and approximately 0.018 kgf/cm, respectively.

Analysis The Effect Of Internal Geometry On The Mechanical Properties Of Acrylonitril Butadiene Styrene (ABS) Materials Prepared Using 3D Printing

The process of research and refinement of Fused Deposition Modeling 3D Printer, surely contains many variables and parameters with the aim of generating a 3D object with the results and the level of accuracy approaching its original design and can be applied as the expected design. In addition to the effect of printer type on the FDM method, the filament material used as a filler to print 3D objects certainly has different mechanical and physical characteristics, thus allowing for different object results for each different filament material. This research was conducted to determine the effect of internal variations of its geometry and dimensions on the mechanical properties of ABS using a 3D Printer. The internal geometries that are varied are triangle and honeycomb, with variations in thickness for each geometry are 1 mm and 2 mm, and variations in the axis of symmetry are 4.5 mm and 9 mm. The results showed that the control sample had tensile and bending strength results that matched the ABS filament datasheet reference. Objects with an internal geometry triangle in the size 4.5 mm and 2 mm of thickness have better tensile and bending strength than honeycomb geometry.

Investigation on Mechanical Properties and Corrosion Resistance of Cobalt-Based Alloy Cladding Layer

Austenitic stainless steel was cladded with Cobalt-based alloy by means of Tungsten inert gas (TIG) welding to improve the performance of the working parts such as the thrust bearing plates under dynamic loads and corrosive liquid. Specimens were prepared with different welding parameters, namely the cladding current, preheating temperature, inter-layer temperature and post heat treatment temperature, so as to investigate their influence on micro-hardness, as well as tensile and bending strength. It is revealed that the lower welding current coincides with higher micro-hardness as well as tensile and bending strength. The higher inter-layer temperature will result inhigher overlay micro-hardness. The post weld heat treatment temperature influences the bending strength of the overlay weld specimens. In addition, the accumulation of Cr and Ni compounds on weldment surface is found to coincide with higher corrosion resistance in over-layers by means of XRD.

Preparation, Structure, and Properties of Surface Modified Graphene/Epoxy Resin Composites for Potential Application in Conductive Ink

The dispersity of graphene (GE) in the matrix has an important influence on the thermal, mechanical, and electrical properties of its derived composites. In this paper, surface modification with a silane coupling agent and a double injection method were used to improve the dispersity of GE in epoxy resin (EP). The thermal, mechanical, and electrical properties of modified graphene/epoxy resin composites (modified GE/EP) were investigated by the thermogravimetric analysis, a four-probe method, and the tensile and bending strength. The results reveal that these properties of the composites can be improved significantly by using the modified GE as the filler. The surface of the modified GE/EP composite was smooth when the curing temperature was 75 °C. The weight loss of the modified GE/EP composite was lower than that of pure EP. The tensile and bending strength of modified GE/EP-0.07 (0.07 wt % modified GE) reached 74.65 and 106.21 MPa, respectively. In addition, the resistivity of modified GE/EP-0.1 (0.1 wt % modified GE) decreased to 52 Ω·cm, which was lower than that of CB/EP-1 (1 wt % carbon black, 95 Ω·cm) and Ag/EP-50 (50 wt % Ag particles, 102 Ω·cm). It is worth noting that the percolation threshold of the modified GE/EP composites was 0.025 vol % modified GE. These results show that the modified GE/EP composites have a potential application in conductive ink when the modified GE is used as the conductive filler.

Effect of the Fibre Type on the Rheological and Mechanical Properties of Cementitious Composites for Thin Overlays

Polypropylene (PP), nylon and polyvinyl alcohol (PVA) micro-fibres with different geometries were used at 1 vol. % dosage to investigate rheological and mechanical properties of cementitious composites to be used for thin overlays. Slump-flow and visual stability index methods were used to characterise the rheological properties. Single crack tension and bending studies were carried out to evaluate the tensile and bending strength, as well as the post-cracking behaviour. The results show that fibre geometry (L/d ratio and specific surface area) has a pronounced influence on the fresh state rheological properties of the cementitious composites. The results also surprisingly indicated that the nylon fibres are able to significantly increase the pre-cracking tensile and bending strength. All tested composites showed tensile strain softening and insignificant deflection hardening after cracking and a major strength loss. The results indicate single crack tension method to be the most appropriate for evaluation of mechanical properties of cementitious composites used for thin overlays.

KARAKTERISASI PENGARUH KECEPATAN LAS PADA PENGELASAN MIG AA5083H116 DENGAN ELEKTRODA ER5356

Indonesia is a maritime country where 2/3 of its territory is ocean. Therefore, many ships are needed for transportation from one island to the nother within NKRI region. The AA5083H116 materials are widely used in maritime transportation vehicle due to its low density and high weldability. The research propose is to characterize the influence of welding speed of Metal Inert Gas (MIG) of AA5083H116 using ER5356 electrode on the welded joint properties. The AA5083H116 materials of 3 mm x 1200 mm x 2400 mm dimension were cut into welding specimens of 3 mm x 75 mm x 300 mm size. Any pair of specimens was welded using electrode of 0.8 mm diameter. The welding parameters being used are 19 volts of electrical voltage, 120 amperes of electrical current, and 8, 10, 12 mm/s of welding speeds. The characterization were carried out on angle distortion that measured using dial indicator on a milling machine table, X-ray radiography test, as well as physical and mechanical properties tests i.e. microstructure, Vickers micro hardness, tensile and bending strength. The research results show that the smallest distortion angle was found at welding speed of 12 mm/s, all of the welding results satisfy the distortion angle of < 5o, and the radiographic results satisfy the DEPNAKER RI regulation standard. The microstructure exhibits Al2Mg3 precipitation, Vickers hardness distributions, while the highest tensile and bending strength were obtained at welding speed of 10 mm/s.