Deflection Characteristics Research Articles

Influence of Nozzle Contraction Ratio and Swirling Flow on Deflection Characteristics in Subsonic FTV Nozzle

Influence of Nozzle Contraction Ratio and Swirling Flow on Deflection Characteristics in Subsonic FTV Nozzle

Numerical analysis on the flow field structure and deflection characteristics of water jets under nozzle moving conditions

High-pressure water jets under nozzle moving conditions are widely utilized for rock breakage in geotechnical engineering. The nozzle motion state significantly influences the jet flow field and flow characteristics, thus changing its rock-breaking performance. In this paper, a single-jet nozzle model with different traverse speeds was established to investigate the jet flow field features and deflection characteristics and analyze the effects of nozzle traverse speed and jet pressure through numerical simulations. The jet flow fields under nozzle fixed and moving conditions were compared in terms of the distributions of vorticity, velocity, pressure and turbulence kinetic energy, and deflection characterization. Jet flow patterns photographed by an ultra-high-speed camera indicated the deflection of the jet flow field under the nozzle moving condition. The simulation results show that the flow field structure of the moving jet contains the non-deflection zone and deflection zone. The jet time-averaged velocity and vorticity are distributed symmetrically in the non-deflection zone, which is similar to the flow patterns under the nozzle fixed condition. As the jet prolongs further, the vorticity value increases and the vorticity distribution is more concentrated and closer to the nozzle outlet in the moving direction owing to more intense turbulence, resulting in the non-self-similarity of jet velocity dimensionless distribution on cross-sections and jet flow deflection to the opposite direction. The faster the traverse speed and the lower the jet pressure, the greater the jet flow deflection degree. The jet centerline velocities decay exponentially with the standoff distance, and the attenuation degree increases as the traverse speed increases. As the standoff distance increases, the jet deflection distance increases in a quadratic parabola and the deflection angle and impact angle both increase linearly, and decrease exponentially with increasing jet pressure. There is a positive relationship between the jet deflection characterization and the traverse speed.

Deviatoric Stress Evolution Laws and Control in Surrounding Rock of Soft Coal and Soft Roof Roadway under Intense Mining Conditions

Aiming at the problem of large deformation and instability failure and its control of soft coal and soft roof roadway under intense mining, laboratory experiments, theoretical calculations, Flac3D numerical simulation, borehole peeping, and pressure observation were used to study the deflection characteristics of the deviatoric stress of the gas tailgate and the distribution and failure characteristics of the plastic zone in the mining face considering the strain softening characteristics of the roof and coal of roadway, and then the truss anchor cable‐control technology is proposed. The results show the following: (1) The intense mining influence on the working face will deflect the peak deviatoric stress zone (PDSZ) of the surrounding rock of the gas tailgate. The influence distance of PDSZ is about 20 m in advance and 60 m in lag; the PDSZ at the gob side of the roadway is located in the range of 3–5.5 m from the surface of the coal pillar, while the coal wall side is mainly located in the range of 3–4.5 m at the shoulder corner and bottom corner of the solid coal. (2) The intense mining in the working face caused the nonuniform expansion of the surrounding rock plastic area of the gas tailgate. The two shoulder angles of the roadway and the bottom of the coal pillar have the largest damage range, and the maximum damage location is the side angle of the coal pillar (5 m). Angle and bottom angle of coal pillar are the key points of support control. (3) The plastic failure line of the surrounding rock of the gas tailgate is always between the inner and outer contours of the PDSZ, and the rock mass in the PDSZ is in a stable and unstable transition state, so the range of anchor cable support should be cross plastic failure line. (4) The theoretical calculations and numerical simulation results agree well with the drilling peep results. Based on the deflection law of the PDSZ and the expansion characteristics of the plastic zone, a truss anchor cable supporting system with integrated locking and large‐scale support function is proposed to jointly control the roof and the two sides, which effectively solves the problem of weak surrounding rock roadway under severe mining deformation control problems realizing safety and efficient production in coal mines under intense mining.

A study on the flexural behavior of sustainable concrete beams with high volume fly ash

Production of cement, the prime ingredient in concrete leads to the emission of large amount of carbon dioxide. Fly ash, a waste product from thermal power plant is emerging as an inexpensive replacement of ordinary Portland cement (OPC). The use of high volume fly ash concrete in beams requires a study on its flexural performance. Hence, this paper presents the flexural behavior of Reinforced Concrete (RC) beams with 50% fly ash as replacement to cement. Four beam specimens with High Volume Fly Ash Concrete (HVFAC) and four specimens with Ordinary Portland Cement Concrete (OPCC) were subjected to two point bending load. Data presented include the deflection characteristics, cracking behavior, ductility indices, moment curvature and end rotations of the beam specimens with sustainable concrete. The study found that the moment capacity of the HVFA beams was slightly more than that of the OPCC specimens at the end of 56 days and also the deflections under design service loads were within the allowable limits. The HVFA specimens also exhibited lesser embodied energy and embodied carbon as compared to OPCC specimens.

Simulation and Experimental Substantiation of Beam Deflection under Guided End Conditions

This paper studies the nonlinear deflection characteristics of a rectangular cross sectional beam with guided support conditions. In this study two different end conditions namely guided – guided and guided – simply supported have been examined. Beams made with two dissimilar materials for instance, aluminum and steel have been considered for this study. Different loading conditions namely point load and the amalgamation of uniformly distributed load and point load have been taken into account in this study. The nonlinear response of a beam under static loading condition is influenced by various parameters like sectional properties of the beam, material, loading and boundary conditions etc. A separate loading fixture was fabricated using steel to apply the load (Point load and uniformly distributed load). The loading fixture was validated by performing an experimental measurement of the deflection under various loading conditions on a simply supported beam. The corresponding theoretical displacement values were calculated using the findings in literature and compared with test results .Both the results were found matching with each other with an average variation of just 10%. Based on this validation lesson, the loading fixture was incorporated in the actual study. Displacement values from the nonlinear static analysis were predicted using Finite Element Method and correlation was made with the experimental values for the actual beam setup. Close correlation among the numerical and physical test results was achieved and the maximum error was 8%.

Evaluation of Self Weight Deflection Property of GFRTP Laminate at Moulding Temperature and Formability Simulation of Diaphragm Forming

The application of Glass Fibre Reinforced Thermoplastics (GFRTP) is expected to reduce the weight of automobiles. In order to use GFRTP for automotive parts, it is essential to apply Computer Aided Engineering (CAE) technology. Until now, prepreg sheets with thermosetting resin matrix are assumed to be used for materials in simulation software. When FRTP is applied for materials in simulation software, it is required to grasp the characteristics of FRTP under moulding temperature. In our previous study, a system capable of evaluating the tensile properties of FRTP laminates at moulding temperatures had been developed and their tensile properties had been evaluated. Bending stiffness under moulding temperature is also required for simulation software. While bending stiffness can be determined using Young's modulus for isotropic materials, thermoplastic prepregs have large anisotropy, especially at moulding temperature. In this study, a system that enables self-weight deflection test of thermoplastic resin laminate under moulding temperature was developed and self-weight deflection characteristics of plain weave GFRTP were evaluated. The analysed results in which the bending stiffness under the moulding temperature of GFRTP was taken into account, gave the most suitable results to the experimental results.

Ductility Analysis of Beams Reinforced with Super Elastic Shape Memory Alloys

Ductility of the beam is important phenomenon while calculating the strength of any structure. This paper discusses the ductile behavior of beam reinforced with super elastic shape memory alloys. Before initiating the experimental program preliminary properties of shape memory alloys (SMA) were defined and concrete properties are defined by casting standard cubes. Experimental program consists of two point load test on a beam reinforced with SMA. Beam is loaded to know the ultimate deflection. Load deflection characteristics and deformation of the beam are analysed to study the ductile characteristics.

Study on Flexural strength of RC Beams Using Polymer Infiltrated Steel Fiber Laminates

An experimental investigation is made for strengthening of RC beams. This research is currently being focused on the use of correct material for repair and strengthening of existing reinforced concrete structure and the research is also concern about the effective utilization of aggregate in construction industry due to scarcity of natural resources. Strengthening can be done by using polymer which includes high steel fiber. Here crimpled steel fiber is used having 0.5mm diameter and aspect ratio of 50. This study is meant for analyzing the flexural behavior of external bonded reinforced concrete beam. The external strengthening is need for increasing durability & serviceability of the member. In total four number of beam specimens were casted and tested less than two points loading. Out of four specimens, one was conventional and for the next beam laminates bonded at bottom and beam bonded at bottom and lateral faces and beam laminated by all the four sides. The cross sectional dimension of beam 1100 mm x 100 mm x 150 mm. Load deflection characteristics of the specimens were studied and energy absorption were calculated. An analytical model was created with ANSYS and the experimental results were compared with the software.

Strength and deflection characteristics of concrete reinforced with steel swarf

This paper reports the strength characteristics of concrete reinforced with steel swarf at varying percentages. A total of forty-five concrete specimens were investigated; with a mix proportion of 1:2:4 and water-cement ratio of 0.55, fifteen numbers each of 150mm concrete cubes, 150x300mm concrete cylinders and 150x150x750mm beams, were cast and tested for density, compressive, tensile and flexural strengths. The results showed that workability of Swarf Reinforced Concrete (SRC) is not significantly affected at 0.5% steel swarf content but decreased as the percentage of steel swarf increased. The density of SRC increased as the percentage of fibres increased, due to the material property of the steel swarf. The compressive strength of swarf concrete as compared to normal concrete was found to increase by 1.7%, 4.8% and 5.6% for 1%, 1.5% and 2% swarf content respectively. The obtained increase in the tensile strength was 5.2%, 3.9%, 13% and 26% for 0.5%, 1%, 1.5% and 2% swarf content respectively. Using regression analysis, Index models for compressive strength and tensile strength with respect to the swarf content was developed at high coefficient of correlations (R2 values) of 0.9398 and 0.9601 respectively. The maximum failure load recorded for swarf concrete was 2.5 times higher than that of plain concrete. The significant increase in the failure loads for the 1.5% and 2% steel swarf content is an indication that there was good bond between the concrete and the steel swarf. The maximum deflection of 0.57mm was recorded for swarf concrete beams. This is an increase of 103% compared to plain concrete beams. The SRC is able to sustain further deformation under increased load; this is as a result of increased load carrying capacity and ductility of the beam section, which is due to the strength and ductility properties of the embedded steel swarf.

Numerical Analysis of Semi-rigid Asphalt Pavement Deflection under Dynamic Traffic Load

In order to detect dynamic deflection rapidly and continuously, a dynamic model under traffic load of asphalt pavement finite element was built, dynamic deflection with different traffic speeds and different point were studied; the dynamic deflection with different thickness of pavement layers and different dynamic modulus were also studied. Results show that the dynamic deflection is different with different traffic, the higher the speed the smaller the deflection, and the maximum deflection lags the peak traffic loads; road pavement thickness increased significantly reduced dynamic deflection, the order of thickness impact dynamic deflection was the surface layer, the base and subbase; the layers modulus increases the dynamic deflection reduced. Findings contribute to developing continuous and rapid dynamic deflection testing equipment based on dynamic deflection characteristics of the road surface.

Experimental Analysis of Epoxy Bonded B eams with GFRP L aminates

External wrapping or retrofitting of polymer sheets are used in concrete and reinforced concrete structures is an increasing trend present. This paper evaluates the flexural behavior of beams retrofitted externally with GFRP laminates. Experimental plan deals with static experimental analysis. Reinforced beams of sizes 200×250×3500mm are casted for a grade of M35. Reinforced beams are externally retrofitted with E-glass fiber polymers. Beams are epoxy bonded to the GFRP laminates. Beams are tested under monotonic two point concentrated loading. Load – Deflection characteristics, crack pattern and failure characteristics of beam are analyzed.

Magneto-electro-elastic analysis of piezoelectric–flexoelectric nanobeams rested on silica aerogel foundation

This article explores that the study on bending of magneto-electric-elastic nanobeams relies on nonlocal elasticity theory. The Vlasov’s model foundation utilizes the silica aerogel foundation. The guiding expressions of nonlocal nanobeams in the considered framework are used extensively and where parabolic third-order beam theory is achieved after using Hamilton’s principle. Parametric work is introduced to scrutinize the influence of the magneto-electro-mechanical loadings, nonlocal parameter, and aspect ratio on the deflection characteristics of nanobeams. It is noticed that the boundary conditions, nonlocal parameter, and beam geometrical parameters have significant effects on dimensionless deflection of nanoscale beams.

Tensile Strength and Deflection Characteristics of Friction Stir Welded Aluminum Aa 6351 Alloy Joint

Tensile Strength and Deflection Characteristics of Friction Stir Welded Aluminum Aa 6351 Alloy Joint

Modelling and analysis of SU8/CB nanocomposite polymer flow sensor

This paper studies the effect of diaphragm size and stylus design on flow measurement characteristics of a polymer flow sensor. The sensor is made of two piezoresistive SU8/CB nanocomposite polymer cantilevers integrated with diaphragm carrying a free standing stylus its centre. The fluid flow drag force deflects the stylus which in turn deforms the anchoring cantilevers and changes their electrical resistivity. Finite element analysis software ANSYS Multiphysics used to determine the deflection, stress and sensitivity characteristics of the flow sensor at different velocities. Results show that sensitivity of flow sensor decreases with increase in diaphragm size and square stylus has better sensitivity.

Characteristics of current digital single-use flexible ureteroscopes versus their reusable counterparts: an in-vitro comparative analysis.

Single-use flexible ureterorenoscopes (fURSs) have been recently introduced aiming to offer solutions to the sterilization, fragility and cost issues of the reusable fURSs. In order to be a viable alternative, the single-use scopes must prove similar capabilities when compared to their reusable counterparts. The goal of our in-vitro study was to compare the current reusable and single-use digital fURSs regarding their deflection, irrigation and vision characteristics. We compared in-vitro 4 single-use fURSs-LithoVue™ (Boston Scientific, Marlborough, Massachusetts, USA), Uscope™ (Zhuhai Pusen Medical Technology Co. Ltd., Zhuhai, Guangdong Province, China), NeoFlex™ (NeoScope Inc, San Jose, California, USA) and ShaoGang™ (YouCare Technology Co. Ltd., Wuhan, China) versus 4 reusable fURSs-FLEX-Xc (Karl Storz SE & Co KG, Tuttlingen, Germany), URF-V2 (Olympus, Shinjuku, Tokyo, Japan), COBRA vision and BOA vision (Richard Wolf GmbH, Knittlingen, Germany). Deflection and irrigation abilities were evaluated with different instruments inserted through the working channel: laser fibres (200/273/365 µm), retrieval baskets (1.5/1.9/2.2 Fr), guide wires [polytetrafluoroethylene (PTFE) 0.038 inch, nitinol 0.035 inch] and a biopsy forceps. A scoring system was designed to compare the deflection impairment. Saline at different heights (40/80 cm) was used for irrigation. The flow was measured with the tip of the fURS initially straight and then fully deflected. The vision characteristics were evaluated (field of view, depth of field, image resolution, distortion and colour representation) using specific target models. Overall, the single-use fURSs had superior in-vitro deflection abilities than the reusable fURSs, in most settings. The highest score was achieved by NeoFlex™ and the lowest by ShaoGang™. PTFE guide wire had most impact on deflection for all fURSs. The 200 µm laser fibre had the lowest impact on deflection for the single-use fURSs. The 1.5 Fr basket caused the least deflection impairment on reusable fURSs. At the end of the tests, deflection loss was noted in most of the single-use fURSs, while none of the reusable fURSs presented deflection impairment. ShaoGang™ had the highest irrigation flow. Increasing the size of the instruments occupying the working channel led to decrease of irrigation flow in all fURSs. The impact of maximal deflection on irrigation flow was very low for all fURSs. When instruments were occupying the working channel, the single-use fURSs had slightly better in-vitro irrigation flow than the reusable fURSs. The field of view was comparable for all fURSs, with LithoVue™ showing a slight advantage. Depth of field and colour reproducibility were almost similar for all fURSs. ShaoGang™ and Uscope™ had the lowest resolution. FLEX Xc had the highest image distortion while LithoVue™ had the lowest. Partial field of view impairment was not for Uscope™ and ShaoGang™. In-vitro, there are differences in technical characteristics of fURSs. It appears that single-use fURSs deflect better than their reusable counterparts. Irrespective of deflection, the irrigation flow of the single-use fURSs was slightly superior to the flow of the reusable fURSs. Overall, reusable fURSs had better vision characteristics than single-use fURSs. Further in-vivo studies might be necessary to confirm these findings.

Application of external prestressing on the rehabilitation of reinforced concrete beams

Concrete structure experiencing any form of distress due to multiple reasons; need remedial, strengthening, and rehabilitation measures, if the structure is to attain serviceability and strength requirements of different elements. Further, the external welding reinforcement and prestressing of the reinforced concrete members have been proven to provide an effective strengthening approach. The prestressed concrete describes a type of concrete where internal stresses are instituted to counteract the multiple tensile stresses that are characteristics of service loading. In these concrete structures, cables, hard-drawn wires or bars of high strength alloy steel are employed as tendons to generate the counteracting stresses. The prestressed concrete is made up of an active combination of steel and concrete as these materials are traditionally stressed before the application of external loads. The prestressing technique has been comprehensively reviewed in numerous articles showing that it is more effective than the RCC structures. External prestressing is emerging as an essential component of prestressing as it is structurally attractive and economical. In external prestressing, the tendons are placed outside the member to improve the load-bearing capacity of the structures and their members. In this study, a beam exposed to various loading condition and distress is strengthened using external prestressing. The ultimate deflection and failure characteristics were evaluated using different loading scenarios; beam weight, live weight, and dead weight. The results for the prestressing analysis was provided for 10 and 20 strands.

Comparison of the Load Deflection Characteristics of Esthetic and Metal Orthodontic Wires on Ceramic Brackets using Three Point Bending Test

Comparison of the Load Deflection Characteristics of Esthetic and Metal Orthodontic Wires on Ceramic Brackets using Three Point Bending Test

A parametric study on geometrically nonlinear behavior of curved beams with single and double link rods, and supported on moving boundary

The paper presents a parametric study on effect of several geometric parameters on stress and deformation behavior of non-uniform curved beam with moving boundary. The parameters, considered in the present study, are height to span ratio of curved beam, ratio of radius of roller support to height of beam and types of support connection mechanisms. Effect of these parameters is observed for different curved profile shapes. Non-uniform initial curvature and combined effects of bending, stretching and warping of beam cross-section due to shear deformation are considered in the derivation of nonlinear strain-displacement relation in body fitted curvilinear frame. Based on the derived nonlinear kinematics and assumptions of large deformation but small strain and moderate initial curvature, nonlinear system governing equation is derived through variational principle based minimization of total potential energy method. An iterative numerical solution algorithm is developed and implemented in the computational environment of MATLAB® software to solve the nonlinear governing equation. The complicating effect coming from moving boundary imposes a kinematic constraint on the solution field. Hence, the solution methodology not only ensures energy balance of the system, but also satisfies shear force balance at each incremental load step. The geometric nonlinear incremental curved beam model is validated with deflection and stress results of commercial finite element software ABAQUS®. The geometry of master leaf spring of a previously reported study is considered as curved beam for the purpose of validation. After the validation study, results are generated for different curved profiles with two different combinations of support connection mechanisms and different height to span ratio for each type of them. In addition, to observe effect of roller radius, results are generated with different roller radius to height ratio for each type of the two curved beam systems. Investigations are made on the effects of the geometric parameters, support connection mechanisms and curved profile shape on large deflection characteristics of curved beam and the present study leads towards several meaningful observations.

Energy Characteristics and Failure Mechanisms for Textile Spread Tow Thin Ply Thermoplastic Composites under Low-velocity Impact

Carbon composites are deemed suitable for components with complex geometries which require high impact resistance. The broad range of industrial applications requires composite structures to be lighter and not to compromise with their mechanical performance. Non-crimp fabrics with lower fibre areal weight (FAW) are the class of reinforcement material which will only bring the advantages of better mechanical properties but will also offer more longevity to the structures and reduced maintenance costs. This research aims at investigating the low-velocity impact performance of textile spread tow thin ply (100 gsm) composites with an aim to study the load bearing capability, deflection characteristics and energy characteristics. The results are compared with the baseline thick (200 gsm) fibre reinforced composites. There was 19.2 %, 16.6 %, and 6.57 % higher peak load for spread tow thin ply composites when compared to thick ply composites at 25 J., 42 J., and 52 J impact energies respectively. Significantly lower residual deflection (40 % to 76 %) and higher major damage energy (20 % to 33 %) were observed for spread tow thin ply laminates compared to the thick ply variant at different impact energies. At 42 J and 52 J impact energies, the damage index (DI) was 2 times and 4 times higher for Thick ply laminates highlighting extensive damage, which is also observed with detailed failure mechanisms study.

Experimental Investigation on Performance of Helical Spring Lock Washer Under Different Operating Conditions

In mechanical systems, emphasis has been given to the selection and health monitoring of both bolt and nut in the bolted joint assembly; less attention has been given to the performance of spring washers due to tightening torque, usage duration and reuse. In the present experimental investigation, the load–deflection characteristics of helical spring lock (HSL) washer during compressive loading and unloading are determined using newly designed and developed test rig. Also, the load–deflection characteristics of the HSL washers are examined for reuse cycles. Additionally, the effect of compressive loading and unloading on the reaction load within elastic limit is determined. Further, the loss of helix height due to compressive loading and its effect on strain energy is examined. The tests have evidenced of loss of helix height and strain energy of HSL washer due to compressive loading which deteriorates its functionality in further usage.