Papers by Keyword: Stiffness

Abstract: The purpose of this study is to compare the impact strength of epoxy composites made of basalt fiber reinforced polymer (BFRP) with those that have nanoclay filler. The matrix materials were Epoxy resin (LY556) and Hardener (HY951), the reinforcing material was basalt fiber, and the filler was warmed montmorillonite nanoclay with a volume percentage of 4%. nanoclay was preheated to 45°C for 40 minutes. The fiber of basalt The control group is epoxy composite (N=20). An experimental group (N=20) of epoxy composite reinforced with basalt fiber and 4% nanoclay filler is created using the hand layup technique. The two groups samples are tested. Results are analyzed using the SPSS-V26 statistical tool, the basalt fiber with 4% volume fraction of warmed nanoclay filler epoxy composite shows the better impact strength, the mean significant difference is p<0.048. The impact strength of BFRP composites containing 4% volume fraction of nanoclay is 9.14% higher than that of BFRP composites without filler, according to the study's limitations.

Abstract: The article presents and describes the methodology for determining the fire resistance limit state of loaded thermally stressed steel floor beams. The article describes the methodology for taking into account the uneven temperature distribution along the height of the cross-section of a fireproofed steel floor beam. The author presents a method for refining the stiffness characteristics of an I-beam after exposure to high temperatures from a fire and compares the results with the results of field tests.

Abstract: The selection of biomaterials and the design of the scaffold is crucial, as it directly influences the mechanical properties, which in turn affect cell behavior and tissue integration. This study investigates how scaffold geometry impacts mechanical characteristics, with the aim of replicating the properties of natural tissues. Auxetic geometries, characterized by negative Poisson’s ratios, were investigated. These structures exhibit unique mechanical behavior, expanding laterally when stretched, in contrast to conventional materials that contract. The Fused Deposition Modeling (FDM) technique was used to 3D print scaffolds with a single filament of polycaprolactone (PCL). Two geometries, wavy and sinusoidal, were analyzed by varying the amplitude of the curve within each structural cell. Tensile tests were performed to measure mechanical properties, including Young’s Modulus (E), Poisson’s ratio (ν), and porosity-properties critical for understanding the interaction of scaffolds with cells and tissues. The wavy geometry exhibited a higher E than the sinusoidal geometry at the same amplitude. At a minimum amplitude of 0.3 mm, the wavy structure had E = 6.8 MPa, while the sinusoidal structure had E = 3.8 MPa. At the maximum amplitude of 1.2 mm, the wavy structure had E = 0.6 MPa, and the sinusoidal structure had E = 0.2 MPa. All Poisson’s ratios were negative, with the lowest value (-1.56) observed in the sinusoidal structure at the largest amplitude. The detected negative Poisson’s ratio suggests auxetic behavior, which could enhance scaffold flexibility, improve its ability to deform, promote cell attachment, and facilitate tissue integration. Although the two auxetic structures shared the same undulation angle, the analysis revealed differences in their mechanical properties. Specifically, the wavy structure exhibited a lower Young’s Modulus. To improve cell interaction and attachment by reducing pore size, a correction factor was calculated based on stiffness values and pore area measurements. By adjusting the scaffold geometry, its mechanical properties can be fine-tuned to more closely align with the characteristics of native tissues, potentially enhancing cell attachment and proliferation. This study highlights the potential of modifying scaffold geometry, particularly through the use of auxetic structures, to significantly influence mechanical properties. This approach shows promise in optimizing scaffolds for tissue engineering applications.

Abstract: This study explores the integration of GiD pre-processing software with ETABS to enhance the finite element modeling of large, complex, multi-story buildings under diverse loading conditions. The research highlights the benefits of using GiD for customized meshing of slab systems, which allows for precise control over mesh density and element quality. Through a case study of an eight-story reinforced concrete structure, the study demonstrates how GiD improves analysis accuracy and computational efficiency by reducing process time and minimizing mesh-related errors. The results indicate that GiD’s refined meshing capabilities enhances the structural model’s accuracy, improving load distribution, straining actions calculations, deflection accuracy, and load transfer representation under gravity loads. In addition, GiD’s approach leads to more reliable predictions of natural periods, lateral displacements, and story drifts under seismic conditions. This integration offers valuable insights for engineers seeking to optimize FEA workflows for complex structures.

Abstract: In this paper, the vibration model has been suggested to study the local defects in the deep groove ball-bearing system. MATLAB is used to solve the equations governing the bearing system to simulate its vibration signals. The vibration model of the deep groove ball bearing system is constructed and takes into account the masses of the housing, balls, races, and shaft in addition to the damping at the ball-race interface and different-sized race defects. The effect of different defect sizes on the measured load distribution has been analyzed and discussed. The contact deformation and load distribution for a fault-free bearing system as well as for faults with β_ball=5⁰ and 40⁰ circumferential extents are measured and displayed for interpretation. Due to de-stressing and losing all or some of its ability to support a load, the load that a ball placed inside the defect zone previously carried has been split between the balls outside of the defect region. This implies that balls lose all or part of their load-bearing capacity when they are positioned in the defect zone, increasing the static loading on the raceway sections without any defects. Moreover, it is seen that the radial clearance, applied load, and defect shape all significantly affect the load redistribution that follows the loss of load-bearing capacity.

Abstract: Beam-column joint is the most vulnerable location of a moment-resisting reinforced concrete frame structure. The joint region experiences the maximum shear stress both in vertically and horizontally which is generated due to the shear transfer mechanism from the adjoining beams and columns. The shear capacity and bond stress capacity are the two major factors affecting the strength of a joint core in RC structure. An important discovery recently is the ductile behaviour of the whole structure under repeated loading. The behaviour of the concrete beyond elastic limit which is in the concrete hardening zone can drastically influence the ductility of the concrete. The non-linear stress-strain behaviour after the onset of the initial crack and up to ultimate compressive strength plays an important role in improving ductility. Beyond the ultimate compressive strength, concrete will undergo softening which is neglected in this study as once concrete reaches ultimate stress it is unsafe for service. This material ductility can be fulfilled with the application of high-strength fibres with ductile behaviour. However, the hybridization of two or more fibres can incorporate two different characteristics of the fibre used. The use of ordinary-grade of concrete moreover reduces the shear-resisting capacity of the joint. A hybrid mix of hooked-end steel fibre with basalt fibre and crimpled steel fibre with polypropylene fibre are used with a volume fraction of 1% to 1.4% of the concrete. In this study, ordinary M25 grade concrete and fibre mixed M25 grade concrete is employed under static and cyclic loading. The laboratory tests are also conducted to evaluate the compressive strength, split-tensile strength, and flexural strength of the hybrid mix fibre-reinforced concrete at the age of 28^th days. Five full-scale models of the beam-column joint are designed as per the Bureau of Indian Standards. Numerical models of concrete and steel reinforcement are developed. Numerical analysis is carried out using finite element software ANSYS-v21. The behaviours of the beam-column joint are observed under static as well as cyclic loading. Crack patterns, first crack load, initial displacement, ultimate load, and ultimate displacement are observed under static conditions. And under cyclic loading, hysteresis load vs displacement, energy dissipation, and stiffness degradation are observed. The hybridization of hooked steel with basalt fibre gives better results in mechanical strengths and the hybrid effect of crimpled steel with polypropylene fibre gives better results in mechanical strengths. And also under numerical study, the above specimens show an improvement in energy dissipation capacity. Keywords beam-column joint, hybrid fibre reinforced concrete, numerical concrete model, ANSYS, static, reverse cyclic, energy dissipation, stiffness, crack

Abstract: The purpose of this study was to examine the recoil effect in jumping on a Korean teeterboard, a circus equipment resembling a seesaw. To our knowledge, our study is the first to include detailed measurements of bending movement of the teeterboard per section. Two elite acrobats performed 120 jumps while a motion capture system collected kinematic data from both acrobats and the teeterboard. Board bending angles and timing were analyzed with a Boosted Regression Tree (BRT) model to identify the most important teeterboard variables associated to jump height. The BRT model showed that both the board recoil effect and the landing of the opposite acrobat influenced 46% and 37% of the jump height, respectively. The recoil timing was found to be synchronized with the last contact at take-off. Coaches should encourage acrobats to take advantage of the recoil effect to increase jump height in Korean teeterboard.

Abstract: This research work aims to perform a comparative study on the effect of fiber orientation distribution (FOD) on the mechanical properties of composite laminates for aircraft and automobile structure. The objective of this project works is to use an analysis method to study the effect of significant parameters namely, with and without orientation on the glass fibre epoxy composites. The experimental work is used to investigate the mechanical behavior and to examine the properties with respect to fibre orientation on the composite laminates. The glass fibre orientation characteristics for the composite laminates is considered since they affect the strength of the specimen laminates. In this connection, the specimens were fabricated with different orientations and undergone for mechanical testing like tensile, compression and impact tests with Data Acquisition System. The experimental results indicate that the specimens with orientation provide more strength, high stiffness and good toughness than the normal specimens without orientation.

Abstract: A study was carried out to test unitary as well as multi-segmental circular and noncircular glass-reinforced plastic pipes under compression. Three pipe shapes were tested (box, semi-elliptical and round) under identical conditions using the ring stiffness method of testing. Hand layup technique was used for manufacturing the pipes. The pipes were designed with inner layers, central core and outer layers. The inner layer acts as the corrosion barrier layer, the core consists of blended sand impregnated with resin and the outer layer acts as the external layer which protects the pipe from impact. Based on the experimental results, it was concluded that multi-segmental pipes are stiffer and more flexible than unitary pipes because of the loading carrying capacity of the tongue and groove joint (TGJ).

Abstract: Transport industry plays a vital role in development of economy of countries. To increase the load carrying capacity of the truck, the weight of truck bed may be reduced using fibre reinforced composite material. In this work, a numerical investigation is performed to reduce the weight of the truck bed using different types of laminated composites. An extensive study is conducted using unidirectional and woven fibres of glass, carbon and Kevlar fibres with polyester, epoxy and vinyl ester resins. Carbon fibre laminated plates have higher stiffness than Glass and Kevlar composite plates. Asymmetrically hybrid composite plates have lower stiffness than symmetrically hybrid composite plates. It is observed that the stiffness of plate is increased when kevlar unidirectional fibres are arranged at top and bottom of the laminate. [K/G_w]_S hybrid composite plates has the lowest deflection than other five hybrid composite plates. An optimization study is performed to identify the influencing parameter for deflection of the composite materials among material type, fibre volumetric fraction and the thickness of plate using Taguchi method. The results revealed that thickness of the plate has more influential than other two parameters.