Research on Engineering Structures and Materials

643-658

Authors: Lemiye Atabek Savaş

ß-strontium hydrogen phosphate nanosheets (SHPs) with a thickness range of 35-50 nm were synthesized by hydrothermal method using strontium nitrate (Sr(NO3)2) and diammonium hydrogen phosphate ((NH4)2HPO4) as reagents. Polypropylene (PP)/SHP nanocomposites were prepared using melt blending technique with different filler concentrations ranging from 1 wt.% to 7 wt.%. Composites were characterized primarily by tensile test, flexural test, thermogravimetric analyses and ball-on-disc sliding wear test. Experimental results revealed that the inclusion of nanosheets into PP improved the thermal stability of the composites. In addition, the tensile and flexural properties of the composites improved with SHP loading. A maximum increment of 6.0 % in tensile strength compared to pure PP was observed at 7 wt.% SHP concentration, and flexural strength of the composites was found to be higher than that of the pure polymer at each filler concentration. However, an increase was observed in the friction coefficient and wear rates of the composites due to increased hardness and rigidity of the matrix with the addition of SHP, which produced micro-cutting and micro-plowing actions that caused increased abrasive wear of the composites.

675-694

Authors: Nasir Mohammed Tahir, Adamu Umar Alhaji, Ibrahim Abdullahi

Finite Element Method such as Abaqus software is increasingly used to analyze structures such as the Unmanned Aerial Vehicle Wing. Unmanned Aerial Vehicle is usually fabricated using synthetic materials such as Glass fibers, Carbon fibers and Kevlar. The problems with the synthetic fibers are environmental pollution during processing, energy consumption during processing and cost of production. Natural fibres can be used as replacement for synthetic fibers due to their comparable physical and mechanical properties. The research involves the simulation of an Unmanned Aerial Vehicle wing made from 5% Cold Alkaline treated 5% SterculiaSetigeraDelile fiber (SSD) at 0-degree orientation and 7.5% PterocarpusErinaceus (PTE) Wood dust Epoxy composite using Abaqus software. The wing was subjected to aerodynamic wing loading from 167.57N to 895N (3kg to 16kg). The result showed that the wing produced using the Novel material could withstand the most critical flight load distribution in conformation with Federal Aviation Regulation (FAR) part 23 Airworthiness standards with an ultimate design load of 5.7. At the point of failure the wing could withstand an Ultimate load factor of 20.26. Structural physical testing was performed for a wing loading of 167.75N to 335.50N (3kg to 6kg). The wing successfully resisted the critical in-flight loading confirming the simulation result. The Novel material of lower density (1.093g/cm3) could withstand the wing loading requirement making it suitable for the UAV wing application.

707-720

Authors: Prem Kumar V, Vasugi V

The increase in population promotes the construction industry to exploit the conventional building materials. This phenomenon leads to use of alternative building materials in the construction field. One of the effective natural materials is bamboo. In this paper, the Bamboo Fibre (BF) is used as an additive in the mortar at various percentages (1% to 4%) and Bamboo Stem Ash (BSA) is used as an alternative binder material to replace the cement at different proportions (2.5% to 10%). To increase the property of mortars, Styrene butadiene rubber (SBR) is used a super plasticizer from 0.5% to 2%. Due to high raising demand of river sand, Copper slag (CS) is used partially to replace the fine aggregate at constant percentage (50%) for all the mix proportion. W/B ratio is proportioned from 0.35 to 0.5 at different level. The design of experiment is conducted through Taguchi’s design and the experimental values are validated by Artificial Neural Network (ANN) tool for obtaining the predicted results with respect to dry density, water absorption, compressive strength and flexural strength. The experimental investigation proved that BF and BSA have a potential sign to be used as an alternative sustainable building material. From the comparative analysis of experimental results with ANN, it is revealed that the mortars show an acceptable prediction of physical and strength properties with a maximum error of 8.11%.

735-749

Authors: Olatunji Oladimeji Ojo, Gbadebo Samuel John

The weldability of the interlocked-end friction stir welding (IFSW) of aluminum plates was studied via the use of single and double-sided welding procedures. The abutting ends of the Al plates were milled into equidistant slots (with 5 mm rise and 10 mm span) and an interlocked/meshed end profile was formed when two slotted plates were brought together. The friction stir welding of the interlocked end of the plates was carried out at different tool rotational (700 – 1120 rpm) and traverse (21 – 63 mm/min) speeds while the structure, tensile strength, and fracture behaviors of the resultant welds were examined. The results showed the presence of flow-induced defects in the welds irrespective of the adopted welding procedure. Relative to the single-sided welds, the severity of the weld defect was significantly reduced in the double-sided welds due to dual material plasticization, material consolidation, and twofold recrystallization advantages. Improved tensile strength (from 39.6 to 69.1 MPa), reduced area fraction of flow-induced defect, and a large area with ductile features are obtained in the double-sided IFSW weld. A double-sided welding procedure is recommended for the interlocked-end friction stir welding process.

773-798

Authors: Tanvi Saxena, V.K. Chawla

Nano-fillers are bringing impeccable development in the area of materials science and natural fibers reinforced composites. In this study, a composite consisting of banana-carbon fiber reinforced epoxy matrix filled with 1%, 3%, and 5% weight percentage of nano-clay particles (NC) and carrying a transverse load is investigated for its mechanical and elastic properties. Nano-clay layer with interphase are arranged in layers called nano-clay platelets. The elastic properties such as longitudinal elastic modulus, transverse elastic modulus, in-plane Poisson’s ratio, in-plane and out-of-plane shear modulus for the proposed composite are calculated by using different analytical models namely, Mori-Tanaka, Bridging, Generalized Self-Consistent, and Modified Halpin-Tsai model. The strength and deformation of the proposed composite are analyzed by using the ANSYS APDL application. The proposed composite is modeled using two layers of banana fibers, two layers of carbon fiber, and one layer of nano-clay platelet. The fibers and nano-clay platelet are arranged in a specific sequence of banana fiber at 900, carbon fiber at 00, nano-clay platelet at 900, carbon fiber at 00, and banana fiber at 900. The proposed composite reinforced with 3% nano-clay is showing the least deformation as compared to 1% and 5% reinforcement. It is also observed that the modified Halpin-Tsai model outperforms all the other models as it is yielding the most effective elastic properties for the proposed composite and Mori-Tanaka model is found to be the least effective model for the calculation of elastic features of the proposed composite. Additionally, the hybridization effect for the composite is also calculated to analyze the tensile failure strain characteristics for banana and carbon fibers in the hybrid composite.

811-834

Authors: Altin Bidaj, Huseyin Bilgin, Marjo Hysenlliu, Irakli Premti, Rrapo Ormeni

A prolonged earthquake series hit the regions of Albania on September 21 and November 26, 2019, causing loos of live and extensive damage to the civilian structures. The main aim of this study is to investigate the structural and earthquake response of a template design, commonly encountered in the region, which was seriously damaged by the 2019 Durres/Albania earthquake. A 3D mathematical model of the entire structure was prepared, implementing macro-modeling approach to simulate its response under seismic shakings. Inherent material properties of its constituents were determined experimentally and adopted for the analytical model. Initially, an eigenvalue analysis was deployed to identify the dominant vibrations modes of the structure. Then, pushover analyses were performed to assess the earthquake response of the template designed structure, and possible failure mechanisms were examined. Finally, the obtained results from the software were compared with the real-life damage experienced by the building. In the end, it was observed that the analytical model proved to accurately estimate the earthquake behavior exhibited by the structure during the seismic shaking.

853-860

Authors: Om V. Vaidya, Kapil Malviya, Yuvaraj L. Bhirud

In today’s world, renovation and demolition is very common. This creates an aggregate waste. One can recycle this waste. Most of the waste that is generated from demolition of structures is dumped in landfills to reclaim land. These create a waste which contain concrete, bricks and other construction material which is of no use. By gathering all these waste and recycled it. The recycled concrete aggregate is created. Transport costs is very high that’s make it even worse. Therefore, recycling of RCA (Recycled Concrete Aggregate) is eco-friendly, which reduces the harvesting of Natural concrete and that aggregate might be used for the production of concrete for new construction. Recycled Aggregates Concrete uses demolition concrete and burned clay masonry structures as aggregate. In this research work the demolition waste is used in concrete and the properties were discussed using Compressive strength test, Flexural strength test, Split tensile test with 0, 30, 60 and 100 percent RAC.

885-904

Authors: Mahesh V. Raut

The production of fly ash is mounting steadily every year all over the globe, but the rate of recovery is insufficient compared to its production. The disposal of fly ash is becoming more and more difficult in India. Reusing fly ash for some valuable uses is one of the most convenient solutions to this problem. As a result, the present study has focused on the use of high volume fine grain fly ash as a partial alternative material for cement and sand with a low volume fraction of glass fiber. Glass fiber reinforced concrete mixtures consisting of up to 40% replacement of cement and sand by fly ash were produced for making sustainable concrete. The experimental work was carried out by preparing diverse mixes with a 0.40 water-cement ratio and analyzing the fresh as well as hardened properties of mixes. The experimental results reveal that the separate and combined replacement of cement and sand by fly ash together with glass fiber, enhance the durability and strength of concrete. When combining 20% of cement and 40% of sand replaced by fly ash together with glass fiber, better result was observed than all other mixes. The compressive strength, electrical resistivity (ER), and ultrasonic pulse velocity (UPV) increased by 36.33%, 65.82%, and 7.25% over control mix (C0-0). This discovery is very useful for making dense, durable and sustainable concrete by using proposed mixes.