Section Moment Research Articles

Reduced trabecular bone mineral density and thinner cortices in men with distal forearm fractures.

Men with distal forearm fractures have reduced bone density, an increased risk of osteoporosis and of further fractures. The aim of the study was to investigate the structural determinants of these observations using quantitative CT (qCT). Ninety six men with low-trauma distal forearm fracture and 101 age-matched healthy control subjects were recruited. All subjects underwent a quantitative CT on a standard 64-slice whole body CT scanner. These were analysed on Mindways QCT PRO™ Software to generate volumetric and geometric data at the lumbar spine, femoral neck and total hip, ultra-distal and distal 33% radius. Biochemical investigations, health questionnaires and measurements of bone turnover were made. Men with fracture had significantly lower total and trabecular vBMD at all sites. The greatest percentage reduction was at the ultra-distal radius (13.5% total and 11.7% trabecular vBMD). In the fracture group cortical vBMD was significantly higher in the femoral neck (p<0.001) and maintained at the ultra-distal radius compared with control subjects. However, cortical cross-sectional area (CSA) and thickness were significantly reduced at the femoral neck (p<0.001 and p=0.002 respectively) and forearm sites (CSA ultradistal radius p=0.001, cortical thickness p=0.002, CSA distal one third radius p=0.045 and cortical thickness p=0.005). Cross sectional moment of inertia (CSMI) and section moduli were significantly reduced at the femoral neck (CSMI1 p=0.002, CSMI2 p=0.012 and section moduli Z1 p<0.001, Z2 p=0.004) and the ultra-distal radius (CSMI1 p=0.008 and section moduli Z1 p=0.018, Z2 p=0.007). In stepwise logistic regression analysis distal forearm fracture showed the strongest association with a model comprising ultra-distal forearm trabecular vBMD (negative), procollagen type I N-terminal propeptide (PINP, positive) and sex hormone binding globulin (SHBG, negative). In conclusion, these observations explain the structural reasons for the increased fracture risk in men with distal forearm fractures.

A hybrid sectional moment projection method for modeling soot particle dynamics in laminar premixed flames

In this work, a new and robust numerical approach for solving the population balance equations that describe the soot particle dynamics in laminar premixed flames is presented. The new approach is a combination of fixed sectional method and moment projection method, hence the name hybrid sectional moment projection method. It adopts a number of quadrature nodes within each section to describe the complex soot particle interactions. The positions of some quadrature nodes are specially assigned to achieve a better statistical representation of the particle population. The performance of this new approach is first tested using a simplified population balance model under a homogeneous condition, then it is implemented into the PREMIX/OPPDIF code packages to simulate the soot particle dynamics in two sooting reference flames. Results suggest that this new approach is much superior to the conventional fixed sectional method in terms of numerical accuracy and computational efficiency. The evolutions of the particle global quantities as well as the detailed size distribution could be well captured by the new approach using very few sections.

Three-Dimensional and Threefold Nonlinear Numerical Modeling for Slope-Stabilizing Pile

To enhance the accuracy and reliability of the design calculation for reinforced concrete slope-stabilizing pile, a three-dimensional and threefold nonlinear numerical modeling method was proposed. Namely, in the three-dimensional modeling the material nonlinearity is considered with soil modeled with a nonlinear elastic model, and reinforced concrete pile with an advanced damaged plasticity model for the first time in particular. The boundary nonlinearity is considered by using the Coulomb friction to model the interactions on both soil-pile and soil-rock interfaces. And the geometry nonlinearity is taken into account by adopting the large deformation algorithm. In addition, a post-processing approach for the sectional bending moment of pile body is presented when a reinforced concrete pile is modeled with solid elements, and steel bars with truss elements embedded in concrete. The proposed method was successfully applied to model a pilot pile. The same ultimate bearing capacity as the test was obtained. Comparisons also show that the computed displacements and maximum moments agreed well with the measurements regardless of whether the pile was working in the elastic or damaged plastic state, and even the advent of cracking was identical with the test. In addition, the fluctuation phenomenon of moment diagrams of the pile body in the damaged plastic state as well as the spatial distribution of soil resistance were revealed for the first time. The outcomes highlighted the accuracy, reliability and efficiency of the proposed method.

Moment Resistance Analysis of Thin‐walled Stiffened Sections by the Alternative Method of EN1993: Part:1‐3

AbstractThin‐walled sections distortional buckling phenomena is treated in EN1993 part:1‐3 (EC3‐1‐3) through the calculation of reduced thickness of stiffeners group, mainly by the application of the simplified method presented in this specification which comes with a limitation of applicability to non‐standard sections or with multiple stiffeners that can result in over conservative or insecure results.With the objective of facilitating de study/utilization of such kind of sections by designers, maintaining a safe set of results and without the overwhelming amount of calculations, the alternative method in clause 5.5.1(7) is used, applied only to the distortional analysis and correspondent effective thickness of stiffenersThis alternative method allows the use of Linear Buckling Analysis (LBA), which, in this paper, are obtained through the Generalized Beam Theory (GBT) by the GBTUL computer application that applies this theory in the identification of distortional modes and buckling critical loads calculation. The results are then incorporated in EC3‐1‐3 algorithm as defined in clause 5.5.1(7). For the application of this alternative method the LBA results are integrated with EC3‐1‐3 using the Class4Section application, updated for this paper, which uses the critical buckling loads for the calculation of the critical stress of stiffeners group. This more generic approach by the alternative method is easily implemented in computational environment.Following previous work by the authors, the section moment capacity is analyzed in this paper by applying this alternative method and comparing it with available experimental results for selected thin‐walled sections mainly used in flexural problems, namely Sigma and Omega section types, as well as the most commonly known C and Z sections, but with multiple stiffeners.

Research on Deflection of Partial Steel Fiber Reinforced Concrete Beams with BFRP Bars

In this study, the flexural behavior tests of steel fiber reinforced concrete beams with BFRP bars under static load are carried out by means of statics experiment and theoretical analysis. A total of seven beams were designed for this experiment, and the effects of two factors on the mid-span deflection of the beams were investigated with the steel fiber incorporation rate (0%, 0.5%, 1%, 1%/0.5%, 1.5%) and the height of steel fibers in the concrete layer in the compression zone (180 mm, 210 mm, 300 mm) as the main variables. In this study, based on the existing research results and combined with the actual test results, the formulae for calculating the cracking section moment of inertia applicable to BFRP reinforced steel fiber (full section/pressure zone reinforced) concrete beams are derived. At the same time, the results obtained from the formula and the results of the ACI code in the United States are compared with the data of the results obtained from this test, and the calculated results of this formula are in good agreement with the actual values.

Age Related Trends in Structural Indices of Proximal Femur in Women Aged 20-70 in Southern Sri Lanka

Age related trends of the indices of hip structure help understanding how bone strength changes with age and the increased bone fragility in old age. Community-dwelling women aged 20-70years (n = 419) were selected by stratified random method and divided into age categories; 20-29years (n-69), 30-39years (n = 60), 40-49years (n = 69), 50-59years (n = 107) and 60-70years (n = 114). All subjects underwent dual energy x-ray absorptiometry (DXA) and hip structure analysis using Hologic Discovery scanner (Hologic Inc, Bedford, USA). Measured indices included hip axis length (HAL) and neck shaft angle (NSA) of the proximal femur. Cross sectional area (CSA), cross sectional moment of inertia (CSMI), section modulus (SM), cortical thickness (CT), buckling ration (BR) of three regions of interest; narrow neck, intertrochanteric region and femoral shaft, were also measured. Age related trends of all indices were studied with Locally Weighted Scatterplot Smoothing lines (LOESS) and ANOVA. Mean HAL and NSA values were not different between age categories. CSA, CSMI, SM and CT in three different regions showed curvilinear relationships with age. These indices gradually increased with age between 20-50 years and the maximum values were seen in the 40-49years age category and they declined afterwards. The decline of these indices was more rapid in the narrow neck and intertrochanter regions when compared with femoral shaft and the lowest mean CSA, CSMI, SM and CT in these two regions were seen in the 60-70 age category. BR showed a gradual decrease with age between 20-50 years and the lowest mean value was seen in the 40-49 age category. BR increased afterwards and the maximum mean value was seen in the 60-70 age category. This study demonstrates the dynamics of structural properties of proximal femur in the three selected cross sections of community-dwelling women aged 20-70 years and the increased bone fragility in old age.

Simulation of loads on operating device of peat-cutting unit with regard to errors in the cutting elements arrangement

The practice of using units with milling-type operating devices showed their insufficient reliability, which leads to deterioration of the units’ performance. The reasons for this are high dynamic loads in structural members, which are caused by external resistance forces on a milling cutter. They have random, sharply variable nature due to structural heterogeneity of a peat deposit, its random physical and mechanical properties, the presence of wood inclusions in it, as well as periodic interaction of blades with the deposit, and many other factors. In this case, the parameters of actual milling cutter, due to manufacturing and installation errors, differ from those specified in the “ideal” design. In addition, wear and irreversible deformations of cutting elements (blades) occur during operation. As a result the position of blades in a cutter body differs from the “ideal” positioning pattern. The purpose of the paper is to develop a model of section moment on a milling cutter when interacting with a peat deposit in the process of technological operations, taking into account the influence of the error of blade positioning on a cutter body. Expressions for calculating the moment spectral density were obtained. Its characteristic features were analyzed. Errors in positioning of cutting elements on a cutter body lead to changes in the magnitude and nature of the load and its frequency content. In this case, new, additional components appear at frequencies multiple of the cutter’s angular velocity, enriching the load spectrum and increasing its variance. Their magnitude is determined by the cumulative value of the errors. As an example, an analysis of the influence of the error in positioning cutting elements on the spectral density for the operating device of MTP-42 deep milling machine is given. The study results are of practical value and should be taken into account in the calculation of dynamic loads in designing structural members of milling units, especially if their operating devices have a large number of blades, use fine feeds, and when the natural frequencies of the structural members are equal to or multiple of the angular speed of a milling cutter.

Higher BMI and lower femoral neck strength in males with type 2 diabetes mellitus and normal bone mineral density

BackgroundType 2 diabetes mellitus (T2DM) and osteoporosis are two age-associated diseases. Body mass index (BMI) is positively associated with osteoporosis or osteopenia in T2DM population. Bone mineral density does not necessarily reflect the alterations in bone microarchitecture. Our aims were to investigate the relationship between BMI and femoral neck strength in males with T2DM and normal range of bone mineral density (BMD). MethodsThis study enrolled 115 males (median age 53.3 years) with T2DM and normal BMD. Femoral neck strength indexes, including compression strength index (CSI), bending strength index (BSI), impact strength index (ISI), were calculated by parameters generated from Dual-energy X-ray absorptiometry software. Pearson correlation analysis was performed to evaluate the relationships between BMI and femoral neck strength variables. ResultsCompared with T2DM-normal weight group, T2DM-overweight group and T2DM-obesity group had a higher femur neck and total femur BMDs. Cross sectional moment of inertia (CSMI), cross sectional area (CSA), section modulus (SM) were significantly higher (all p<0.05), and buckling ratio (BR) (6.35±2.08 vs 7.18±1.71) was lower in T2DM-obesity group than in T2DM-normal weight group. Compared with T2DM-normal weight group, CSI (all p<0.001), BSI (all p<0.001), ISI (all p<0.001) were significantly reduced in T2DM-obesity and T2DM-overweight groups. Pearson correlation analysis indicated that BMI was negatively correlated with CSI (r= − 0.457, p<0.001), BSI(r = −0.397, p<0.001), ISI (r = − 0.414, p<0.001). ConclusionsHigher BMI is associated with lower femoral neck strength in males with T2DM and normal BMD. It implies that femoral neck fracture risk increases in obese and diabetic males, despite their high bone density.

Pitch/Plunge Equivalence for Dynamic Stall of Swept Finite Wings

A high-fidelity numerical study is undertaken to expand the notion of pitch/plunge equivalence to finite, swept wings undergoing deep-dynamic stall and builds upon the analysis of straight wings in another paper by the authors [“Pitch/Plunge Equivalence for Dynamic Stall of Unswept Finite Wings,” AIAA Journal (submitted for publication)]. The wing has an aspect ratio of with a NACA 0012 section, a rounded tip, and a sweep angle of ; it operates at a Reynolds number of and a Mach number of . Equivalent pure-pitch and pure-plunge motions at two different reduced frequencies are considered to assess pitch-induced apparent camber on the wing and its effects on the three-dimensional flow structure, surface topology, and aerodynamic loading. Regardless of the motion type or rate, the wing undergoes dynamic tip stall that is initiated through the outboard separation of a dynamic stall vortex as it lifts off the surface and forms into an arch vortex before ejecting into the wake. The pitching cases exhibit an advanced development and evolution in time of these features that are observed as variable amplifications of the aerodynamic loading, which is due predominantly to an apparent camber effect. Corrections to the total and sectional lift and moment coefficients are explored by extending steady thin-airfoil theory to pitching swept wings. Remarkably, the corrected plunge-equivalent histories provide a full collapse of the force and moment responses between the pitching and plunging cases, despite the delayed behavior of the flow structure. This equivalence and the similar process of dynamic stall should facilitate the comparison of experiments and/or simulations employing different motion types, even for finite-aspect-ratio and swept wings.

Numerical evaluation of segmental tunnel lining with voids in outside backfill

This paper presents a numerical investigation of the mechanical behaviour of segmental linings owing to the existence of voids in the composite lining. The composite lining was formed by mining outside and shield tunnelling inside with backfill in between. Finite element method was conducted to analyse the axial forces and bending moment for voids of different diameters at different positions. The results show that the axial forces in the transverse section increase near the crown and then invert and decrease on the left and right sides with an increase in the void centre angle (β) measured from the vertical axis. The increase in void diameter (d < 300 mm) induces an increase in the axial force on the left and right sides when β = 45° and 90°, while it decreases near the crown and invert. The occurrence of voids leads to an increase in the bending moment in the entire segment section with an angle β.

Dynamic simulation of the tractor HMCVT under typical working conditions based on AMESim

In order to study the dynamic characteristics of hydro-mechanical continuously variable transmission (HMCVT) under ploughing and sowing conditions, a complete simulation model of HMCVT is established based on AMESim software, including mechanical transmission model, pump controlled hydraulic motor speed control model and section changing hydraulic system model. In addition, the dynamic model of tractor is established. In order to verify the correctness of the simulation model, a test-bed is established. The test of tractor running speed and the test of pump controlled hydraulic motor system were carried out on the test-bed. The test results show that the simulation model of pump control hydraulic system can correctly reflect the change of transmission ratio of pump controlled hydraulic motor, and the simulation model can reflect the actual working condition change of clutch. Thus, the correctness of the previous simulation model based on AMESim is verified. Based on the simulation model established by AMESim, the dynamic characteristics of HMCVT under ploughing and sowing conditions are studied. The results show that: Under ploughing condition, the planetary platoon will have strong impact at the moment of throttle opening and changing section. Under sowing condition, the HMCVT will have a great impact at the time of variable cross section, but the variation range of rodent force decreases and the change trend tends to be stable. Keywords: tractor, HMCVT, AMESim, dynamics simulation, test DOI: 10.25165/j.ijabe.20221502.6815 Citation: Xiao M H, Zhao Y F, Li X H, Hussain G, Wang S J, Zhu Y J. Dynamic simulation of the tractor HMCVT under typical working conditions based on AMESim. Int J Agric & Biol Eng, 2022; 15(2): 102–110.

Structural response of high strength concrete beams using fiber reinforced polymers under reversed cyclic loading

This paper investigates the response of high strength concrete (HSC) beams subjected to reversed cyclic loading using carbon fiber-reinforced polymer (CFRP), glass fiber-reinforced polymers (GFRP), and hybrid FRP/steel bars as bottom tensile reinforcement. Five HSC beams with a rectangular cross-section were prepared and poured using with a 28-day concrete compressive strength of 60 MPa (8.7 ksi). A displacement-controlled reversed cyclic loading has been applied to all the beams. The test setup has been designed to represent seismic effect on structures. Flexural capacity, concrete and reinforcement steel strains, cracking behavior, and ductility results were obtained. The hybrid steel/FRP has shown an improved performance in terms of flexural capacity, strains, and ductility. While the inclusion of FRP grids reduces the flexural capacity, this can be improved by adding more layers of FRP. Overall, the nominal moment of the hybrid sections were the highest between all beams. The ACI 318 code’s empirical equations showed close results in terms of the tensile strength of the FRP. The ACI 440R has shown overestimated nominal moment values compared to the experimental results.

A hybrid sectional moment projection method for discrete population balance dynamics involving inception, growth, coagulation and fragmentation

A new and efficient sectional method is developed and presented in this work. This new method, namely hybrid sectional moment projection method, seeks to combine the techniques of moment projection method and sectional method in a flexible and accurate way. It adopts the concept of weighted particles from moment projection method to handle the particle population dynamics. Special treatment is made on the assignment of these weighted particles within each section so that the accumulation of particles at the smallest size can be better described. The performance of hybrid sectional moment projection method has been tested by comparing with the fixed pivot method and conventional sectional quadrature method of moments in handling a number of particle processes including inception, growth, coagulation and fragmentation. Results suggest that the proposed new method is highly robust and accurate. It is able to well predict the evolution of particle population under various conditions. Especially, it is superior to other sectional methods in the treatment of particle fragmentation process.

Pile group response induced by adjacent shield tunnelling in clay: Scale model test and numerical simulation

The shield tunnelling adjacent pile group was a common phenomenon in urban metro construction, and additional internal force and displacement field of pile group was disadvantageous to existing superstructure. In this paper, a micro shield machine was invented to simulate the shield tunnelling process, and a series of physical scale model tests and 3-D nonlinear FE models were employed to investigate the pile group (2 × 2) response with different minimum distance between pile group and the tunnel central line (Hm) in clay. The results indicated that large additional bending moment and axial force was induced by shield tunnelling, the maximum bending moment was near the tunnel center line, and the amplitude of maximum bending moment in the lateral section (My) was three to five times of that in the longitudinal section (Mx). The maximum lateral displacement emerged at the tunnel central line, and the vertical displacement distributed uniformly along pile length. The negative shaft resistance between pile group and surrounding soil obviously reduced the axial bearing capacity. The shielding effect of the front pile on the rear pile greatly reduced its internal force and displacement, but it gradually weakened with increase of Hm. The internal force and displacement of pile group decreased quickly with increased of Hm. The research results in this paper can provide a reference for the design and construction of shield tunnels near pile group.

Empirical Investigation of a Sufficient Statistic for Monetary Shocks

In a broad class of sticky price models the non-neutrality of nominal shocks is encoded by a simple sufficient statistic: the ratio of the kurtosis of the size-distribution of price changes over the frequency of price changes. We test this theoretical prediction using data for a large number of firms representative of the French economy. We use the micro data to measure the cross sectional moments, including kurtosis and frequency, for about 120 PPI industries and 220 CPI categories. We use a Factor Augmented VAR to measure the sectoral responses to a monetary shock, as summarized by the cumulative impulse response of sectoral prices (CIRP ), under three alternative identification schemes. The estimated CIRP correlates with the kurtosis and the frequency consistently with the prediction of the theory (i.e. they enter the relationship as a ratio). The analysis also shows that other moments not suggested by the theory, such as the mean, standard deviation and skewness of the size-distribution of price changes, are not correlated with the CIR. Several robustness checks are discussed.

Optimization of the parameters of truss beams with two posts

Based on the theoretical results obtained in the article [17], here the analysis of the influence of various design parameters on the own weight and cost of metal of truss beams with two posts is carried out. An optimal parameter has been obtained that makes it possible to reduce the calculated bending moment in the cross section of a truss beam with two struts.Method. By equalizing the bending moments in various design sections of the truss beam, the internal force factors are reduced. The corresponding equation for optimizing the parameters of the beam has been drawn up and a formula has been obtained to determine the optimal parameter of the structure as a whole.Result. Using the example of numerical calculations, a decrease in the calculated bending moment by 14% compared to truss beams without optimization is shown.Conclusion. The proposed method and algorithm testify to the efficiency and rationality of the obtained optimal parameter of the structure as a whole.

LATERAL IMPACT BEHAVIOR OF CFRP-REINFORCED CIRCULAR CONCRETE-FILLED STEEL TUBULAR MEMBERS AFTER EXPOSURE TO FIRE

The numerical model for the lateral impact of circular concrete-filled steel tubular (CFST) members after exposure to fire with and without carbon fiber reinforced polymer (CFRP) is established. The accuracy of the model is verified by different experiments. The whole impact process of reinforced post-fire members is analyzed. The impact force, mid-span deflection and sectional moment of the specimens are compared. In addition, the impact resistance and flexural capacity, plastic deformation and energy absorption capacity, as well as the distribution and development of the internal force are investigated. A simplified calculation formula for the maximum mid-span deflection of the specimens under impact load is proposed. The influence of CFRP reinforcement methods on the impact performance of the post-fire specimens is discussed. The results show that the plateau value of the impact force and the average sectional moment of post-fire specimens were increased by the CFRP reinforcement. However, the mid-span deflection and impact duration were significantly reduced. The impact resistance and flexural capacity of the specimens were significantly improved by the CFRP reinforcement. The impact resistance, flexural capacity and energy absorption capacity gradually decrease with the increase of the fire duration. In addition, the specimens experienced different degrees of plastic deformation at the span, and the energy was mainly absorbed by the formation of plastic hinges. The bending moment and shear force distributions of the specimens under lateral impact at the peak stage were different from those of the specimens under static load, but the distributions at the plateau stage were consistent with those of the specimens under static load. The simplified formula can well predict the maximum deflection of the specimens after lateral impact. The CFRP reinforcement methods have a noticeable influence on the impact resistance of post-fire members.

Optimal design of trapezoid stiffeners of composite cylindrical shells subjected to hydrostatic pressure

Optimization of a composite cylindrical pressure hull subjected to hydrostatic pressure with trapezoidal stiffeners is considered in this paper. The composite cylindrical shell is fabricated with carbon fiber reinforced epoxy composite while the stiffener is made of aluminum alloy. First of all, the analytical buckling model for composite cylinders with stiffeners subjected to hydrostatic pressure is derived. Subsequently, the finite element method is used to verify the accuracy of the analytical solution through some examples. After verification, the analytical solution is coupled with the genetic algorithm and then used to optimize the cross-sectional shape of the stiffeners of the composite pressure hull to obtain the maximum buckling pressure. During the optimization process, the relationship between the buckling pressure and each geometrical parameter of the stiffener has been analyzed. The inertia moment of the stiffener section is found to have a good linear relationship with the buckling pressure. Therefore, the inertia moment is used as an objective function to optimize the cross-sectional shape of the stiffeners of the composite pressure hull, and the feasibility of this method has been proved by comparing the optimization results. With high efficiency, this method can be applied to the optimal design of the stiffener shape of a composite pressure shell.

Active flap control with the trailing edge flap hinge moment as a sensor: using it to estimate local blade inflow conditions and to reduce extreme blade loads and deflections

Abstract. Active trailing edge flaps are a promising technology that can potentially enable further increases in wind turbine sizes without the disproportionate increase in loads, thus reducing the cost of wind energy even further. Extreme loads and critical deflections of the blade are design-driving issues that can effectively be reduced by flaps. In this paper, we consider the flap hinge moment as a local input sensor for a simple flap controller that reduces extreme loads and critical deflections of the DTU 10 MW Reference Wind Turbine blade. We present a model to calculate the unsteady flap hinge moment that can be used in aeroelastic simulations in the time domain. This model is used to develop an observer that estimates the local angle of attack and relative wind velocity of a blade section based on local sensor information including the flap hinge moment of the blade section. For steady wind conditions that include yawed inflow and wind shear, the observer is able to estimate the local inflow conditions with errors in the mean angle of attack below 0.2∘ and mean relative wind speed errors below 0.4 %. For fully turbulent wind conditions, the observer is able to estimate the low-frequency content of the local angle of attack and relative velocity even when it is lacking information on the incoming turbulent wind. We include this observer as part of a simple flap controller to reduce extreme loads and critical deflections of the blade. The flap controller's performance is tested in load simulations of the reference turbine with active flaps according to the IEC 61400-1 power production with extreme turbulence group. We used the lifting line free vortex wake method to calculate the aerodynamic loads. Results show a reduction of the maximum out-of-plane and resulting blade root bending moments of 8 % and 7.6 %, respectively, when compared to a baseline case without flaps. The critical blade tip deflection is reduced by 7.1 %. Furthermore, a sector load analysis considering extreme loading in all load directions shows a reduction of the extreme resulting bending moment in an angular region covering 30∘ around the positive out-of-plane blade root bending moment. Further analysis reveals that a fast reaction time of the flap system proves to be critical for its performance. This is achieved with the use of local sensors as input for the flap controller. A larger reduction potential of the system is identified but not reached mainly because of a combination of challenging controller objectives and the simple controller architecture.

Numerical and FEA investigation of sectional capacity and moment redistribution behavior of steel fiber reinforced concrete (SFRC) beam

Steel fiber reinforced concrete exhibits ductility. This ductility behavior enables redistribution of moment between the negative and positive moment zones in continuous SFRC beams. The sectional capacity of an SFRC continuous beam was determined using the moment-curvature response, the ductility of the member using the moment-rotation response, and the moment redistribution behavior using the moment-rotation response. The theoretical moment-curvature response was calculated from the stress-strain response for 0 % (control), 0.5 %, 0.75 %, and 1.5 % SFRC member which served the basis for the defined moment-rotation behavior and FEA. A five-point bending test was conducted on a two-span beam using a constitutive material model in the FEA software package, Abaqus/CAE. The concrete damage plasticity (CDP) model was used to conduct a displacement-controlled analysis on the fully integrated 3D hexahedral element (C3D8). The numerical study revealed that the flexural behavior, bending capacity, rotation capacity, and ductility of the 0.5 %, 0.75 %, and 1.5 % SFRC beams were significantly enhanced than the 0 % SFRC beam. However, as steel fiber volume increased, the quantity of moment redistribution in the SFRC beam decreased. The amount of moment redistribution obtained was 21.8 % for 0 %, 19 % for 0.5 %, 18.1 % for 0.75 %, and 13.9 % for 1.5 % SFRC.