Maximum Deflection Values Research Articles

Simulation of creep of a rectangular wooden beam under prolonged static load

Objective. Depending on the stress level, the operation of wooden beams under prolonged load is characterized by both linear and nonlinear creep. This has been shown by numerous experimental studies of wood. The theoretical description of these processes is poorly studied or presented extremely rarely. One of the priority areas in the calculations of wooden structure elements is the derivation of resolving equations of linear or nonlinear creep for various types of stress-strain state. Method. The Maxwell-Thomson equations are used as relations establishing the relationship between stresses and deformations. The technique was tested by comparing the solution with the calculation of well-known researchers. An example of calculation is given for various boundary conditions for fixing a beam of rectangular crosssection loaded with a uniformly distributed load. The deflection value is determined by the grid method. Result. A program has been developed for calculating in the MATLAB package with the possibility of varying the initial data and displaying a graph of the dependence of displacement, bending moment on time. The comparison of the maximum deflection value with the analytical solution is given. It is noted that the stresses practically do not change during creep. Conclusion. The proposed approach can be applied to the analysis of the stress-strain state and bearing capacity of wooden beams of arbitrary cross-section. There are no restrictions on boundary conditions and loading type, and the beam material can be not only wood, but also fiberglass.

Increasing the strength of potato digger elevator rods

Abstract Currently, high-quality steels are used to increase the reliability of potato digging machines and the durability of elevator rods. Recently, new materials, new technologies and non-metallic materials that are not inferior in strength to steel have been used in agricultural machines. Such materials significantly reduce the mass of the working parts. This article examines the deformation of a new elevator rod design due to the action of soil and tuber-bearing mass. The rods, covered with double-cavity rubber profiles, vibrate the component of the potato heap. During vibrations, in addition to static deformations, dynamic deformations occur, depending on the magnitude of the impact force. As a result, it was found that to eliminate the loss of tubers between the bars of the separating elevator, given the maximum deflection value of 0.03 m and the weight of the soil-tuber-bearing mass, the rubber bar must have the following parameters: elasticity model E = 50 N/mm2; rod perimeter 11x11 mm; the maximum jump height of a mass weighing 130 kg is no more than 0.6 m.

Analytical method with iteration technique (AMIT) and finite element method (FEM) for predicting the flexural performance of glulam wood/PVC composite hollow member

The flexural performance of a glulam wood/PVC composite (GWPVC) hollow member, which was assembled from four elements with WPVC composite hollow sections to create a double I-section, was studied using two methods: the analytical method with iteration technique (AMIT) and the finite element method (FEM). Experiments verified the predictions from AMIT and simulations from FEM to determine the most suitable method for the parametric studies. This investigation explored the variations in slenderness ratio and the flange and web thickness to enhance and study their impact on flexural performance. In parametric studies, equal cross-sectional areas were used to facilitate comparisons and maintain production costs. The importance of bond strength at the contact surfaces in assembling a GWPVC hollow member led to bonding tests and confirmed sufficient strength at contact surfaces. In four-point bending tests, the GWPVC hollow member exhibited a brittle mode with flexural tensile failure without delamination. The initial MOE, MOR, and maximum deflection values were 5,140 MPa, 29.8 MPa, and 47.8 mm, respectively. The parametric study employs AMIT to investigate flexural performance and reveals that varying the slenderness ratio affected the initial stiffness, maximum deflection, and ultimate load. Flexural performance can be improved by making minor adjustments.

Optimizing the Location of Supports under a Monolithic Floor Slab

Monolithic reinforced concrete floor slabs are one of the most common types of building structures, and their optimization is an urgent task. The article presents the methodology for finding the optimal position of point supports under a reinforced concrete floor slab of arbitrary configuration at arbitrary load. The slab is considered thin, elastic and isotropic, with constant over-the-area stiffness, that is, the reinforcement is not taken into account or is constant. The solution is performed using the finite element method in combination with the nonlinear optimization methods. Finite element analysis is implemented by authors in MATLAB (R2024a) environment in such a way that the location of the columns may not coincide with the nodes of the finite element mesh of the slab. This allows to significantly increase the efficiency of solving the optimization problem compared to previously used algorithms, including the Monte Carlo method. Boundary conditions are taken into account using the Lagrange multiplier method. As an optimization criterion, the maximum deflection value is used, as well as the value of the potential strain energy. The effectiveness of six nonlinear optimization methods is compared in the example of a square slab under the action of a uniformly distributed load. For solutions obtained using the pattern search, simulated annealing and internal point methods, the maximum deflections are at least 1.2 times higher than for solutions obtained using the particle swarm method and genetic algorithm. An example of real object optimization is also presented. By changing the position of seven columns, it was possible to reduce the maximum deflection of the floor slab by 1.6 times.

Dynamic response of GFRP/Nomex honeycomb sandwich panels subjected to multiple hail impacts – An experimental study

AbstractNowadays, more and more aircraft components are made of composite sandwich structures, and ice impacts are prone to cause internal damage to composite sandwich structures, so it is crucial to study the impact of hail on composite sandwich structures. Since hail impacts may occur several times at a single point, an experimental approach was used to investigate the dynamic response of GFRP/Nomex honeycomb sandwich panels under multiple hail impacts. The dynamic response of the structure was investigated in terms of response rate and deflection‐profile curves using 3D digital image correlation methods, and the effects of impact energy, hail size, and number of impacts on the impact resistance of the honeycomb sandwich structure were explored. The results show that the dynamic response process of sandwich panels can be categorized into the ball‐and‐crown phase, the rebound phase, and the vibration phase. Under the same impact energy, the impact of small‐sized hailstones is more threatening to honeycomb sandwich panels. As the number of impacts increases, the maximum deflection value of the back panel first increases uniformly, and when the layered damage area reaches the threshold value, fiber stripping occurs, and the increment of the maximum deflection value increases significantly.Highlights Since hail impacts may occur several times in real situations, this study conducted multiple impact experiments for one impact site. The dynamic response and damage pattern of the GFRP/Nomex honeycomb sandwich panels under multiple hail impacts were also investigated. The dynamic response process of GFRP/Nomex honeycomb sandwich panels was categorized into three phases: ball‐crown stage, rebound stage, and vibration stage. With the increase of the number of impacts, fiber stripping and fiber break damage began to occur when the layered damage area of the panel reached the threshold value. The honeycomb core has three main failure modes: cell wall folds, cell wall fracture, and cell wall debonding at the TGPW interface. Small‐diameter hails pose a more significant threat of damage to honeycomb sandwich panels at the same impact energy.

Predicting multi-span bridge maximum deflection: Numerical simulation and validation

Deflection is one of the main parameters often required to reflect and monitor the overall health state of bridge structures. Several approaches have been developed to monitor deflection accurately and economically. This research proposes a theoretical method to estimate the maximum deflection of the longest section of a seven-span continuous bridge using stress data collected through strain gauges. Firstly, initial data were collected from field tests under various controlled loadings to obtain the maximum deflections and stresses. Then, the stress-deflection regression equations are derived to reconstruct deflection from estimated gauges. Finally, the maximum deflection values are compared with analytical results using finite element simulations to verify the method’s effectiveness.

FINITE ELEMENT SIMULATION ANALYSIS OF STEEL TRUSS ARCH BRIDGE JACKING CONSTRUCTION

In this study, a spatial model of a steel truss arch bridge was established using the finite element software Midas/Civil to simulate and analyze the jacking construction process. The stress performance of the guide beam and main structure at each jacking stage was obtained. The results showed that in the first stage of jacking, the maximum stress and deflection values of the main girder were observed. The maximum stress on the upper edge of the main girder was 34.9MPa, and on the lower edge, it was -60.4MPa. The maximum deflection was -35.88mm. The maximum stress in the guide beam occurred during the jacking process and was -53.2MPa, corresponding to the cross-section at the root of the guide beam. The maximum deflection of the guide beam occurred in the maximum cantilever state and was -30.79mm. During the arch rib jacking process, the maximum stress was -49.4MPa. Both the maximum stress and deflection values were within the allowable range, indicating that the structure was in a safe state. This study provides a reference for similar bridge jacking construction projects.

Effect of Hygrothermal Loads on the Nonlinear Vibration of Porous Bi-Directional Functionally Graded Beams Placed on an Elastic Foundation

In this study, we investigated the effect of hygrothermal loads on the nonlinear free vibrations of a porous bi-directional functionally graded Timoshenko beam with a Winkler–Pasternak foundation. The corresponding governing equations were established according to Hamilton’s principle and von Kármán nonlinearity assumption. Using the differential quadrature and iterative methods, the nonlinear fundamental frequencies were determined. A numerical example was presented, and we showed that the discretization of nonlinear items considerably decreased the number of iterations. A series of parametric studies were performed, and we determined that (1) all the vibration mode shapes were significantly affected by the axial functionally graded index, while they were almost unchanged by the thickness-wise functionally graded index. Moreover, compared to the thickness-wise graded index, the axial functionally graded index played a more important role in the higher-order mode shapes. (2) The geometric nonlinearity considerably influenced the critical temperature rise value of the beams. Increasing the maximum deflection value increased the critical temperature rise value. (3) The influence of increase in temperature and moisture on the nonlinear fundamental frequency became stronger with increase in the functionally graded index, but it weakened with increase in the maximum deflection value.

Active subspace-based performance analysis of supersonic through-flow fan rotor

Abstract This article delves into the intricate relationship between the modeling parameters of an axial supersonic through-flow fan (STFF) rotor and its performance based on an active subspace method. It considers the influence of the STFF rotor key parameters on its performance. Implementing the active subspace method generates cloud maps to visualize the performance of the STFF rotor. Moreover, this study investigates the correlation between Bezier curve variables for constructing blade angles and critical performance metrics, such as the total pressure ratio and isentropic efficiency. After a 50 % chord length, the Bezier control point parameters dominate the effect on the total pressure ratio with a linear relationship. This article provides comparative flow field analyses on the blade elements with different performances under three working conditions. Under the constraint of the blade chamber turning angle, there is a linear relationship between the upper and lower limits of the isentropic efficiency distribution and total pressure ratio. This study shows that the total pressure ratio, installation angle, and maximum deflection value are positively associated. Further analysis provides an empirical formula.

PERENCANAAN FONDASI TIANG BOR PADA TANAH LANAU UNTUK GEDUNG APARTEMEN 20 LANTAI

Foundation is the part of the construction that transmits the load of the superstructure supported by the foundation with its own weight into the soil and rock that lies below it. The purpose of bored pile foundation planning is to design the dimensions of the foundation in the apartment building, calculate the axial and lateral bearing capacity, calculate settlement, calculate the reinforcement used and calculate the cost required for the construction of the bored pile foundation. The bored pile foundation in the apartment building used a circular foundation with a diameter of 0,5 meters which has a depth of 21 meters and located on sandy soil. The axial end bearing capacity of the bored pile uses the Reese & Wright method with a calculated value of 70,450 tons and the ultimate pile bearing capacity of 451,766 tons. Lateral bearing capacity of a single pile using the Evans and Duncan method is 16,359 tons and the maximum lateral bearing capacity of the group is 36,809 tons and the maximum deflection value is 1,419 mm. The bored pile foundation based on the calculation results refers to SNI 2847:2013 concerning Requirements for Structural Concrete for Buildings, for longitudinal reinforcement using 7D19 reinforcement and for spiral reinforcement using D16-40 reinforcement. The budget plan for the foundation and pile cap is Rp. 10.704.000.000.

The effect of aging on the mechanical properties of 3-dimensional printed biocompatible resin materials used in dental applications: An in vitro study

The mechanical properties of biocompatible printable resin materials in an intraoral environment is still being investigated. This study aimed to assess the effect of the aging process on the mechanical properties of resin samples produced by stereolithography appearance (SLA) and digital light processing (DLP) 3-dimensional printer systems. The cylindrical sample (4.00 × 20.00 mm) was designed by software, and the data were transformed into digital format. A DLP printer (n= 40) and an SLA printer (n= 40) carried out the printing process. The aging procedure was applied to 20 samples from each group using a thermocycling device. After the aging procedure, the samples were placed in the universal testing device for the 3-point bending test. This study showed that the aging procedure decreased maximum load, bending stress, and Young's modulus values and increased maximum deflection values of the DLP group (P<0.01). However, no statistical difference was detected in the parameters compared with the SLA group except for the maximum deflection values. Furthermore, statistically significant differences were found between maximum deflection and Young's module values of SLA and DLP control and study groups (P<0.05). This invitro study revealed that the biocompatible printable resin materials produced by DLP and SLA printers had the mechanical strength to resist the values resembling the physiological occlusal forces even after the aging procedure and could produce intraoral appliances.

Optimization of Aluminum Alloy Formwork Geometry Parameters Based on a PSO-BP Neural Network

To assist in addressing the problem where an aluminum alloy formwork (AAF) deforms more greatly under the action of lateral pressure and therefore does not meet the requirements of plaster-free engineering, we propose a method for determining the geometric parameters of this formwork based on a PSO algorithm and BP neural network with ABAQUS as the platform. The influence of six geometric parameters of the formwork on the maximum deflection value of the panel under the action of lateral pressure is studied using finite element analysis. The maximum deflection value of the panel is used as the index, and the influence of each factor is analyzed with an orthogonal test, and a set of optimal geometric parameters is obtained via extreme difference analysis and analysis of variance. The sample data are obtained via finite element simulation, and the PSO-BP neural network model is established using the six factors of the orthogonal test as input values and the maximum deflection of the panel as the output value, and the optimal geometric parameters are optimized using the PSO algorithm. The results indicate that the maximum deflection for the panel in the orthogonal scheme is 1.446 mm. The PSO-BP neural network prediction model demonstrates greater accuracy and a 31.74% reduction in running time compared to the BP neural network prediction model. The optimized PSO-BP neural network prediction model scheme reveals a maximum panel deflection of 1.296 mm, a 10.37% decrease compared to the orthogonal solution. These findings offer technical guidance and a foundation for optimizing AAF designs, presenting practical applications.

PERANCANGAN 3D PRINTING CARTESIAN BERBASIS FUSED DEPOSITION MODELLING DENGAN UKURAN 200 X 200 X 200 mm

The technology of adding manufacturing or 3D printing is one of the main issues in the concept of technology 4.0. The construction design of the 3D printing machine and the deflection of its construction significantly affect the accuracy of the dimension and shape the printed product. The study aims to obtain a construction design of a cartesian type 3 D printing machine based on fused deformation modelling, and to verify the maximum value of the deflection of the machine axis. The study method used VDI222, calculation analysis, and Finite Element Analysis (FEA) simulation using CAE Solidworks software to verify the strength and deflection of the machine design construction. The study results show the construction design of 3D printing machine has been obtained according to the requirement. The verified maximum deflection value is 0.036 mm, hence the maximum error in the dimensions and shape of the printed product for each layer will still be within the standard tolerance. In addition, its maximum deflection value is verified within the radial clearance value of each determined machine axis bearing.

Structural performance of buried reinforced concrete pipelines under deep embankment soil

Purpose Buried pipelines under various soil embankment heights are cost-effective alternatives to transporting liquid products. This paper aims to assist pipeline architects and professionals in selecting the most cost-effective buried reinforced concrete pipelines under deep embankment soil with minor structural reinforcement while meeting shear stress requirements, safety and reliability constraints. Design/methodology/approach It is unfeasible to experimentally assess pipeline efficiency with high soil fill depth. Thus, to fill this gap, this research uses a dependable finite element analysis (FEA) to conduct a parametric study and carry out such an issue. This research considered reinforced concrete pipes with diameters of 25, 50, 75, 100, 125 and 150 cm at depths of 5, 10, 15 and 20 m. Findings According to this research, the proposed best pipeline diameter-to-thickness (D/T) proportions for soil embankment heights 5, 10, 15 and 20 m are 8.75, 4.8, 3.5 and 3.1, correspondingly. The cost-effective reinforced concrete (RC) pipeline thickness dramatically rises if the soil embankment reaches 20 m, indicating that the soil embankment depth highly influences it. Most of the analyzed reinforced concrete pipelines had a maximum deflection value of less than 1 cm, telling that the FEA accurately identified the pipeline width, needed flexural steel reinforcement, and concrete crack width while avoiding significant distortion. Originality/value The cost-effective thickness for the analyzed structured concrete pipes was calculated by considering the lowest required value of steel reinforcement. An algorithm was developed based on the parametric scientific findings to predict the ideal pipeline D/T ratio. A construction case study was also shown to assist architects and professionals in determining the best reinforced concrete pipeline geometry for a specific soil embankment height.

Finite element analysis of reinforced concrete curved box-girder bridges

The study presents the design forces of simply supported single-cell reinforced concrete (RC) curved box-girder bridges using a finite element method (FEM) based CSiBridge v.20 software. An existing model has been used to validate the present modelling approach. Models subjected to vertical loading, i.e., dead load (DL) and Indian road congress live load (LL), are considered for investigation. An intensive parametric study examines the maximum values of bending moment (BM), shear force (SF), torsional moment (TM), and vertical deflection (VD) in both girders of bridges. The influences of curve angle and span are considered in the study. The effect of curve angle, up to 12°, is negligible on forces and deflections, and thus such bridges can be analysed as a straight one. Finally, non-dimensional equations are derived for evaluating forces and deflections, so that one may predict these quantities for curved bridges based on straight bridge’s results. Engineers and designers may consider present work valuable in analysing, and designing curved box-girder bridges.

In vitro examination of fracture resistance of 3D-printed resin blocks in different diameters

Objectives: The intraoral use of commercial printable polymers in dental patients is still a challenge due to the unknown physical properties of the materials. The present study aimed to comparably evaluate the maximum load and deflection values of three-dimensional-printed resin blocks in different diameters that can be used intraorally in dental patients. Material and Methods: Forty-five cylindrical resin blocks in diameters of 2 mm (Group 1, n = 15), 3 mm (Group 2, n = 15), and 4 mm (Group 3, n = 15) and lengths of 20 mm were designed and printed. The samples were placed in the universal testing device to conduct the 3-point bending test. According to the Shapiro–Wilk normality test results, Kruskal–Wallis and Mann–Whitney U tests were performed for the statistical analysis. The level of statistical significance was accepted as P &lt; 0.05. Results: The values for the maximum load (N) and deflection (mm) in the study groups were 218.4 ± 31.9, 2.96 ± 0.86 in Group 3; 77.05 ± 61.5, 3.91 ± 0.92 in Group 2; and 19.67 ± 2.63, 4.06 ± 1.02 in Group 1, respectively. The mean values of maximum load for Group 3 were superior to Group 2 (P = 0.020) and Group 1 (P = 0.00). Group 2 revealed higher maximum load results than Group 1 (P = 0.003). The mean values of maximum deflection in Group 3 were lower compared to Group 2 (P = 0.014) and Group 1 (P = 005). Conclusion: The results of this in vitro study encourage the use of resin-printed intraoral appliances in place of conventional treatment modalities.

Research on the Mechanism and Control Technology of Coal Wall Sloughing in the Ultra-Large Mining Height Working Face.

One of the primary factors affecting safe and effective mining in fully mechanized mining faces with large mining heights is coal wall sloughing. This paper establishes the mechanical model of the coal wall and uses the deflection theory for the mechanics of materials to find the maximum point of the deflection of the coal wall, which is the most easily deformed and damaged during the mining process, based on the mining production conditions of the 12-2up108 working face in the Jinjitan Coal Mine. In order to simulate the characteristics of the coal wall in the large mining height working face at various mining heights, the FLAC-3D numerical method was used. The stability of the mining area was assessed in conjunction with the multi-factor fuzzy comprehensive evaluation mathematical model, and the corresponding control of the coal wall was suggested. The study demonstrates that: (1) The working surface at Jinjitan Coal Mine 112-2up108 is a typical drum-out sloughing. The coal wall is most likely to sustain damage at the point where it contacts the roof when the frictional resistance between the coal seam and the roof and floor is less than the uniform load, and at 0.578 times the mining height when the frictional resistance between the coal seam and the roof and floor is greater than the uniform load. (2) In the working face with a large mining height, mining height of the coal wall is one of the significant influencing factors. With increasing mining height, the coal wall's height also rises nonlinearly, as does the depth of the coal wall in the working face with the large mining height. The growth is linear. The coal wall's maximum deflection value point moves up and the slab's height significantly increases when the mining height exceeds 7.5 m. (3) The Jinjitan Coal Mine should be supported by a pressurized and enhanced composite support bracket with a support force greater than 0.245 MPa and a support plate of 3500 mm because it belongs to a Class I stable coal wall, according to a thorough evaluation of a multi-factor fuzzy mathematical model. The working face's mining pressure is continuously and dynamically monitored, and the stress is released in a timely manner to prevent the occurrence of dynamic disasters.

Calculation and Analysis of Load Stress on Typical Semirigid Base Asphalt Pavement

The linear elastic Bisar software was used to calculate the mechanical properties of a typical semirigid pavement structure. Based on the concept of structural strength coefficient, the fatigue life of each pavement structure layer was deduced. The results show that: (1) the maximum value of deflection was obtained at x=3r/2, the maximum of the surface stress was obtained at X=r/2 and Y=0, and the peak of the principal shear stress at the bottom. (2) At the same time, the horizontal load, road surface deflection, and the maximum stress position of the surfacing surface are invariably applied at the same time. The deflection changes little, and the maximum principal stress increases faster than the maximum shear stress. (3) The cracking order of the structural layer is as follows: shear cracking of surface layer to bending and cracking of surface layer to bending and cracking at the bottom of base layer to bending and cracking at the bottom of semirigid base to bending and cracking at the bottom of the surface layer. The inner edge of a single circle is the destroying source of asphalt pavement, and the initial damage is shear bending failure. Therefore, the durable pavement should consider the principle of structural layer cracking from bottom to top and to prevent the early destruction of the surface layer. (4) The cracking of the base layer will be reflected to the semirigid base and surface layer, which is the first step of structural damage, so strengthening the construction quality of the subbase is an important measure to reduce road damage.

Novel thin polymeric magnetic membranes study for applications in the future biomedical devices

Biomedical devices such as pumping/mixing fluids, cell-culturing, and drug delivery often use different actuation methods. Magnetic actuation using magnetic particles that are embedded in thin flexible polymeric sheets (membranes) is convenient to use, especially for medical implantable devices such as micropumps, due to the fact they do not require board batteries and exhibit better performances than other actuation methods. The fabrication process of these membranes uses a random distribution of particles. In this work, membranes with a local distribution of magnetic particles are investigated and compared to membranes with randomly distributed magnetic particles, which in turn may enhance the actuation performance for certain applications. Iron oxide particles are embedded into polydimethylsiloxane, and micromagnets are used to localize the position of the magnetic particles within the polymeric mixture during the fabrication process. Three different concentrations are investigated: low (7.5 w/v%), medium (10 w/v%), and high (12.5 w/v%). Static and dynamic measurements of membrane’s maximum deflection values are compared for both types of membranes with a random and a local distribution of magnetic particles. The maximum deflection location is shifted due to the presence of the localized magnetic field for a membrane with a local distribution of magnetic particles. From the experimental results, it is evident that the deflection performance result is much higher for the local distribution of the magnetic particles’ membrane during a static magnetic load and slightly lower during a dynamic (sinewave input) magnetic load at frequencies of 1 and 5 Hz.

Investigation of Offshore Wind Turbine Structure Deflection Using Experimental Work, Numerical, and Theoretical Approach

Electrical energy from offshore wind turbines is an important source of clean, renewable energy production. One of the reasons for the low efficiency of wind turbines is the change in the flow angle of attack, denoted by the symbol (α), as a result of the deflection of the structure. The study aims to know the values of the maximum deflection of the proposed structure under the environmental conditions of the Arabian Gulf water area. Our research adopted a novel approach to extracting results; the characteristics of sea waves were extracted from the experimental work after fixing five sea waves, knowing the displacement of the top of the structure, and using the numerical approach in the ANSYS-Fluent program to know the average wind and wave forces. Two simulations were performed. The first included the five cases of sea wave characteristics without rotating wind turbine blades. The second was for the fifth case only with the wind turbine blades rotating at a speed of (20.5 rpm), assuming that the structure was exposed to a constant wind speed (12 m/s) for the two simulations. The study also included obtaining the maximum deflection value of the structure. Then, the equations of the theoretical approach were developed based on the Euler-Bernoulli bending moment equation, and the forces extracted from the simulations were entered into the theoretical equations to extract the maximum deflection values of the structure. Reading the experimental work resulted in the highest displacement of the top of the structure in the fifth case (0.178 m). The result of the second simulation had the highest value of the structure deflection (0.201 m). In comparison, its value came in the theoretical approach (0.160 m), which adopted the forces of the second simulation.