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This study delves into the flexural behavior of concrete beams incorporating Euphorbia tortilis cactus (ETC) as an environmentally friendly additive. Six sets of reinforced concrete beams with varying compositions, including ETC and reference concrete, were subjected to two-point load tests. The results revealed several critical findings. All tested beams exhibited a flexural mode of failure, indicating a ductile response. ETC-incorporated beams displayed superior load-carrying capacity, with initial crack loads increasing by up to 47.9%. ETC beams exhibited lower crack widths, reduced deformations, and enhanced stiffness. The stiffness gradient relative to the ultimate load demonstrated the improved resistance of ETC beams. Energy absorption was significantly higher in ETC beams, signifying their capacity to withstand energy fluctuations. ETC fibers effectively prevented pull-out failures. Overall, ETC-enhanced concrete beams exhibited enhanced performance, highlighting their potential for sustainable construction. [ABSTRACT FROM AUTHOR]

To investigate the flexural performance of Steel-FRP Composite Bars (SFCBs) reinforced Ultra-High Performance Concrete (UHPC) beams, eight concrete beams with different reinforcement ratio, types of concrete were designed and fabricated. Flexural performance tests were conducted to examine the effect of various parameters on bearing capacity, deflections, crack patterns, ductility, and failure modes. The results indicate a significant enhancement in the flexural capacity of tested beams with UHPC. The bearing capacity of SFCB–UHPC beam is higher than that of steel-reinforced UHPC beams, but less than that of FRP (Fiber-Reinforced Polymer) reinforced UHPC beams. The deformation and crack resistance ability of SFCB–UHPC beams fall between those of steel-reinforced UHPC beam and BFRP-reinforced UHPC beam. Increasing the concrete strength and SFCB reinforcement ratio can significantly enhance the deformation and crack resistance ability of SFCB–UHPC beam. All tested specimens exhibited ductile failure. At the serviceability limit state controlled by deflection/crack, the steel-reinforced UHPC beams and BFRP-reinforced UHPC beams exhibit the highest and lowest utilization factors of flexural capacity, respectively, and that of SFCB–UHPC beams falling in between. High-ductility UHPC enhances energy absorption, ductility, initial and secant stiffness. The reinforcement type has a minor impact on the energy dissipation of flexural beams. SFCB, on the other hand, enhances the ductility, initial and secant stiffness of specimens. Based on a simplified material constitutive model and fundamental assumptions, three failure modes for the SFCB–UHPC beam under bending were defined, along with their respective criteria. This enables the establishment of a simplified load capacity calculation formula. With reference to ACI440.1R-03, a stiffness calculation formula was developed to predict the deformation of SFCB–UHPC beams. This research can provide a technological reference for the design and analysis of SFCB-reinforced UHPC beams. [ABSTRACT FROM AUTHOR]

Adding steel fibers into concrete was considered as one of the most effective ways to restrain the crack development and improve the stiffness for reinforced concrete (RC) structures. To explore the reinforcement mechanism of steel fibers on the fatigue behavior of high-strength RC beam, eight high-strength steel fiber reinforced concrete (HSSFRC) beams subjected to fatigue loading were tested in this study. The main design parameters considered in this work were stress level and steel fiber content. The failure mode, crack patterns, fatigue life, crack width, and stiffness degradation of HSSFRC beams under fatigue loading were discussed. The results showed that steel fibers could significantly increase the fatigue life, restrain crack development, and improve crack patterns of HSSFRC beams under fatigue loading compared to ordinary RC beams. Both the crack width and stiffness degradation rate of beams decrease with increasing steel fiber content. Besides, the empirical formulas for calculating the maximum crack width and midspan deflection of HSSFRC beam under fatigue loading were proposed and validated using experimental results.

The impact of the seismic performance of corrosion-damaged reinforced concrete (RC) members on the overall seismic performance of the entire RC structure must be investigated. Related research results provide important guidance for a more accurate seismic performance evaluation of RC structures with corroded members including beams and columns. However, currently available technologies for the seismic evaluation of existing RC structures do not consider the impact of reinforcement corrosion-induced deterioration on the seismic performance of RC members. The main focus of this study is on proposing a practical methodology to evaluate the seismic performance of such buildings. More specifically, the proposed methodology enables a direct quantitative evaluation of seismic performance by estimating the structural performance based on the strength and deformation capacity of corroded members. In pursuit of this research background and the objectives, our research team first performed an experimental study to estimate the impact of reinforcement corrosion on the structural behavior of RC shear beams and flexural beams and determine the factors associated with structural performance deterioration. A high correlation between the half-cell potential (HCP) before and after reinforcement corrosion of RC beams and the structural performance degradation factor based on the energy absorption capacity has been seen previously. In this study, a finite element analysis (FEA) was conducted, in which bond strength loss between rebar and concrete due to reinforcement corrosion of beam members was considered as one of the aging-related degradation factors, and the correlation between structural performance degradation before and after corrosion in beam members was studied. In addition, we compared and analyzed the results of the previous experimental research and FEA conducted in this study and proposed a structural performance degradation factor as a function of corrosion of shear and flexural beams. The research results indicate that the FEA-derived bonding factor (β) and performance degradation factor (ϕ) of flexural beam can be approximated with the equation ϕ = (0.36 − β) − 1 + 101 (R2 = 0.94), together with β–mV (average potential difference in voltage) correlation mV   = (1.36 − β) / (0.018 − 0.05 β) . In the case of shear beams, FEA resulted in ϕ = 37.3 β + 63 , which enables regression approximation, showing a high correlation (R2 = 0.98), together with β–mV correlation ( mV   = 932.5 β − 1075 ). Using the mV–β–ϕ correlation curves, the bonding factor (β) depending on the degree of corrosion of RC beam members and the performance degradation factor (ϕ) based on the consequent strength-deformation capacity can be evaluated. [ABSTRACT FROM AUTHOR]

The cracking of concrete plays a vital important role for the serviceability and durability of reinforced concrete (RC) structures in terms of the structural behavior. To investigate the crack behavior of concrete structure with additional strengthening, monotonic four-point bending test was carried out for RC beams which strengthened with near surface mounted (NSM) prestressing screw-thread steel bars (PSB). Detailed description of the strengthened beams was presented, particularly on the crack initiation and propagation, the distribution, even the crack width and length, based on the deformation fields obtained from the non-contact digital image correlation (DIC) method. In addition, the relationship between the crack width and the damage level was discussed, and based on the results a crack-based damage assessment method for NSM strengthened members was proposed. The results reveal that the beam strengthened with NSM PSB steel bars demonstrated higher load carrying capacity than the reference beam. The prestressing application could significantly increase the cracking load thus delaying the initiation of cracks. The beams NSM strengthened with prestressed bars exhibited more flexural cracks in the constant moment region with a smaller crack width and spacing compared to the specimen without prestress. Furthermore, the crack-based damage assessment method proposed in this paper was demonstrated to be feasible to NSM strengthened beam for determining the damage status and repairability with simple operation. [ABSTRACT FROM AUTHOR]

The impact of the seismic performance of corrosion-damaged reinforced concrete (RC) members on the overall seismic performance of the entire RC structure must be investigated. Related research results provide important guidance for a more accurate seismic performance evaluation of RC structures with corroded members including beams and columns. However, currently available technologies for the seismic evaluation of existing RC structures do not consider the impact of reinforcement corrosion-induced deterioration on the seismic performance of RC members. The main focus of this study is on proposing a practical methodology to evaluate the seismic performance of such buildings. More specifically, the proposed methodology enables a direct quantitative evaluation of seismic performance by estimating the structural performance based on the strength and deformation capacity of corroded members. In pursuit of this research background and the objectives, our research team first performed an experimental study to estimate the impact of reinforcement corrosion on the structural behavior of RC shear beams and flexural beams and determine the factors associated with structural performance deterioration. A high correlation between the half-cell potential (HCP) before and after reinforcement corrosion of RC beams and the structural performance degradation factor based on the energy absorption capacity has been seen previously. In this study, a finite element analysis (FEA) was conducted, in which bond strength loss between rebar and concrete due to reinforcement corrosion of beam members was considered as one of the aging-related degradation factors, and the correlation between structural performance degradation before and after corrosion in beam members was studied. In addition, we compared and analyzed the results of the previous experimental research and FEA conducted in this study and proposed a structural performance degradation factor as a function of corrosion of shear and flexural beams. The research results indicate that the FEA-derived bonding factor (β) and performance degradation factor (ϕ) of flexural beam can be approximated with the equation ϕ=(0.36−β)−1+101 (R2 = 0.94), together with β–mV (average potential difference in voltage) correlation mV =(1.36−β)/(0.018−0.05β). In the case of shear beams, FEA resulted in ϕ=37.3β+63, which enables regression approximation, showing a high correlation (R2 = 0.98), together with β–mV correlation (mV =932.5β−1075). Using the mV–β–ϕ correlation curves, the bonding factor (β) depending on the degree of corrosion of RC beam members and the performance degradation factor (ϕ) based on the consequent strength-deformation capacity can be evaluated.

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The interactive design for industrial applications is today carried out through methods and tools, with different level of accuracy and simulation times. Consequently, the time necessary for virtual prototyping and analysis phases are often long and may be definitely reduced by means of optimization of tools and methodologies. Compliant mechanisms are increasingly used in the industrial field and the design methods are the subject of several studies, to improve their performance and reliability. This paper provides the reader with reliable numerical expressions to describe flexural beams with large deflections in case of combined end loads and without inflection points. Most of the numerical expressions describing beam deflection already existing in the literature are based on elliptic integrals that take into account strict limitations on the maximum slope angle. Here, we go beyond these limitations at the same time trying to give an order to the most relevant formulations used for determining large deflections of beams subject to combined tip loads. The proposed method provides the same results of the comprehensive elliptic integral solution described in a recent study. [ABSTRACT FROM AUTHOR]

The kinematic and dynamic analysis of compliant mechanisms is investigated comprehensively in this work. Based on the pseudo-rigid-body model, a new PR model is proposed to simulate both the lateral and axial deformations of flexural beams in compliant mechanisms. An optimization for the characteristic factors and a linear regression for the stiffness coefficients of PR pseudo-rigid-body model are presented. Compared with the 1R and 2R pseudo-rigid-body model, the advantage of the PR model is well illustrated. The dynamic modeling of flexible beams in compliant mechanisms is then developed based on the PR pseudo-rigid-body model. The dynamic equation of a PR pseudo-rigid-body dynamic model is derived and the dynamic responses are then presented. The kinematic and dynamic analysis of a compliant slider-crank mechanism is presented by the 1R, 2R and PR model, respectively. The effectiveness of pseudo-rigid-body models and the superiorities of the PR pseudo-rigid-body model and PR pseudo-rigid-body dynamic model are shown clearly in the numerical example. [ABSTRACT FROM AUTHOR]

The main challenge in analyzing compliant sensor systems is how to calculate the large deformation of flexural complements. Our study proposes a new model that is called the spline pseudo-rigid-body model (spline PRBM). It combines dynamic spline and the pseudo-rigid-body model (PRBM) to simulate the flexural complements. The axial deformations of flexural complements are modeled by using dynamic spline. This makes it possible to consider the nonlinear compliance of the system using four control points. Three rigid rods connected by two revolute (R) pins with two torsion springs replace the three lines connecting the four control points. The kinematic behavior of the system is described using Lagrange equations. Both the optimization and the numerical fitting methods are used for resolving the characteristic parameters of the new model. An example is given of a compliant mechanism to modify the accuracy of the model. The spline PRBM is important in expanding the applications of the PRBM to the design and simulation of flexural force sensors. [ABSTRACT FROM AUTHOR]

The purpose of this study is to evaluate the effect of hydrated lime addition methods as filler replacement on fatigue performance of Hot Mix Asphalt (HMA). Three types of addition methods of hydrated lime were introduced namely dry HL on dry aggregate and saturated surface aggregate above 3% and slurry HL on dry aggregate, ordinary Lime stone powder was reduced by three HL percentage (1.0, 2.0 and 3.0 %). The effect of different methods were investigated on the fatigue properties of HMA using, third-point flexural fatigue bending Test. Pneumatic Repeated Load System (PRLS) was carried out to establish the effect of hydrated lime on the fatigue failure criteria and to select the proper hydrated lime application methods on fatigue behavior of HMA mixtures. The fatigue functions for asphalt mixture with hydrated lime are obtained and compared, and it confirm that the fatigue property of asphalt mixture can be improved using all methods and the addition methods were exhibited different optimality for the result due to its effect . The test results were carried out through the performance analysis using Vesys 5W (2003) to study the long term effectiveness of hydrated lime effect.

The multiple scattering of flexural waves on a beam with two point scatterers attached to it, where one scatterer has a cubically nonlinear stiffness, is considered. The scattering behaviour is represented by first-order approximations of the reflection and transmission coefficients calculated with a perturbation approach, both at the fundamental frequency and at the generated third harmonic. Due to its nonlinearity and spatial asymmetry, such a system behaves in general nonreciprocally. By analyzing the fundamental-frequency and third-harmonic transmission coefficients, we derive conditions for particular scattering behaviours that result in transmission symmetry for the nonlinear system. We show that a sufficient condition for symmetric fundamental-frequency transmission is that the spacing between the scatterers is a multiple of half the incident wavelength, regardless of the scatterers' properties, although the values of the reflection and transmission coefficients will still depend on the incident-wave amplitude. Such a response is also possible if the real and imaginary parts of the admittance of the linear scatterer satisfy a certain mathematical relation, regardless of spacing. A particular choice of lossless linear scatterer combined with the separation distance being a multiple of half a wavelength leads to fully linear behaviour for the nonlinear multiple scattering system. • Linear-like response is possible in a nonlinear multiple scattering system. • Transmission symmetry in a nonlinear system is achieved by tuning a linear scatterer. • Tuned linear scatterer impedance and position give amplitude-independent transmission. • A tuned linear scatterer half a wavelength from a nonlinear one acts as a linearizer. [ABSTRACT FROM AUTHOR]

Abstract: Based on the pseudo-rigid-body model (PRBM), a 2R PRBM that consists of three rigid links joined by two revolute joints and two torsion springs is proposed in this study. A method of parametric approximation to the deflection path and deflection angle of a flexural beam is developed for the 2R PRBM. A two-dimensional optimization for the characteristic radius factors and a linear regression for the spring stiffness coefficient are presented. Although the model parameters are dependent on the loading conditions, the 2R PRBM is useful in increasing the modeling accuracy of the 1R PRBM and reducing the computation time of the 3R PRBM. The advantage of the new model is also illustrated through a comparison of deformation energies among the various kinds of PRBM and the flexural beam. An application example of compliant mechanism is presented using the 2R PRBM. The 2R PRBM is significant to expand the applications of pseudo-rigid-body model in the analysis and design of compliant mechanisms, particularly in the further study on the dynamics of compliant mechanisms. [Copyright &y& Elsevier]

Abstract: This paper deals with flexural concrete members reinforced longitudinally but without transverse reinforcement. The conducted experimental investigations have shown that beams without web reinforcement may fail without attaining their full flexural capacity and then shear governs their failure. In the paper, there are presented recent results of the author’s own experiments, which aimed at disclosing some aspects of the propagation of cracks in longitudinally reinforced concrete beams without stirrups. The experimental program has been designed to investigate the influence of the shear span-to-depth ratio on diagonal crack propagation and load carrying capacity of tested beams. The obtained test results were compared with numerical results made on the basis of Finite Element Method. In the performed numerical simulation the same longitudinally reinforced concrete beams as in the test were considered. During the numerical analysis, the special attention was paid on a tensile stress distribution and on changes of diagonal crack propagation in dependence of the shear span-to-depth ratio in calculated beams. [Copyright &y& Elsevier]

An object transport system is an essential device in the factory automation system (FAS). Generally, an object transport system is driven by a conveyor belt system or a magnetic levitation system. However, contact force in the conventional transport system can damage precision optical components, while the magnetic field can destroy the inner structure of the semiconductor. The ultrasonic transport system transports objects on an elastic body using an ultrasonic wave. When an ultrasonic wave is applied to a flexural beam, the flexural beam vibrates to excite the air layer, which lifts up the object on the beam to transport. In this paper, the dynamic characteristics of the ultrasonic transport system are theoretically analyzed. Through normal mode expansion, the modeling equation for steady state response of ultrasonic vibration is expressed and the natural frequency of the flexural beam in each mode is also estimated by using the finite element method (FEM). [ABSTRACT FROM AUTHOR]

Abstract: Damping ratio is the main parameter representing the property of materials in vibration reduction. In this study, simply supported beams were tested using a free vibration method to determine the relationships between damping ratio in small deformation and the size as well as amount of rubber particles in rubberized concrete. Elastic wave method and beam element method were used to test the dynamic modulus of rubberized concrete. A comparison between the static modulus and the dynamic modulus was also conducted. It was observed that the damping ratios of rubberized concrete improved considerably compared to those of normal concrete. The dynamic modulus elasticity of rubberized concrete was lower than that of normal concrete. The crushed rubberized concrete had better damping properties but lower dynamic and static modulus of elasticity than ground rubberized concrete. The results of the study provide valuable information for a better understanding of dynamic properties of rubberized concrete. [Copyright &y& Elsevier]