Characteristics Of Bending Moment Research Articles

Bending test and simulation of carbon fiber aluminum honeycomb sandwich structure

According to the bending moment characteristics of carbon fiber aluminum honeycomb sandwich structure for the solar wing in use, this paper simulates and analyzes the large-scale bending samples and tests the bending samples at room temperature, 150 °C, and -150°C. The test results show that the bending performance is not different between low-temperature environment and room temperature environment, but the stiffness and strength at high temperature are reduced by 54.9% and 50%, respectively, compared with room temperature. Compared with the room temperature test results, the simulation results are about 10%, which can roughly reflect the bending performance characteristics of sandwich structures.

Dynamic and Residual Pore Water Pressure Response of Hybrid Foundation System Under Combined Action of Wind, Wave and Seismic Loading

The dynamic response characteristics of the innovative marine wind power hybrid foundation under combined action of wind, wave and seismic loading are studied in this article. Taking the monopile foundation as reference group, the shearing strain-volumetric strain coupled pore pressure incremental constitutive model was utilized to simulate the kinetic behavior of seabed’s saturated soil. The pressure distribution and variation characteristics of residual pore water pressure around pile foundation due to the interactions of upper structure, foundation and saturated soil are illustrated. The results indicate that: (a) the cylindrical platform changes the residual pore water pressure and accelerates the pressure accumulation area, which converts from surrounding the monopile to nearby the cylindrical platform; (b) compared to the hybrid foundation, the peak value of residual pore water accumulation of the monopile foundation is smaller only under seismic loading, which is due to that the monopole with smaller stiffness is more vulnerable to deform with soil synergistically; (c) the cylindrical platform structure can significantly reduce the horizontal placement extreme of pile foundation under the action of dynamic load, and can also change the distribution characteristics of bending moment of middle pile of the hybrid foundation. It is manifested by a lower bending moment extreme of the middle pile near the mudline under the action of wind and wave loading, while the seismic loading could increase the bending moment extreme of middle pile near the mudline.

The impact of geofoam on the bending moment characteristics of reinforced concrete box culverts for road under bridge (RUB) design

Reinforced concrete (RC) box culverts for Road under Bridge design (RUB) have been widely used in the construction of railways. RUB box culverts are typically exposed to dead loads, live load intensities from dynamic effects, and lateral earth pressure. The amount of reinforced concrete in the box culvert depends on the expected lateral earth pressure and superimposed dead loads from the top filling material. The magnitude of increased vertical load from the top filling material generates stresses and deformations on all the faces of the box culvert. To counteract the high pressure, either more reinforced concrete in the box culvert or lightweight material as backfill is used. Expanded polystyrene (EPS) geofoam as a lightweight geosynthetic is commonly used in transportation infrastructure to minimize horizontal and vertical stresses on culverts. This research investigates the effect of top filling properties on the bending moment characteristics of two cell reinforced concrete skew box culverts for the RUB design. The STAAD Pro software was used to model and analyze the cast-in-situ RUB box structure with profiles of 10.5 × 5.6. For this study, the fill height above the top slab of the culvert has been varied from 0.5 m to 10 m with increments of 0.5 m. The structure was analyzed for two different top filling materials; initial (with normal soil) and then with EPS geofoam materials. The results of the study indicate that using geofoam as a top-filling material reduces the bending moment on the center of the top slab of the box structure, midspan of the bottom slab of the second cell, and bottom edge of the outer wall of the second cell by 76 %, 70 %, and 73.3% respectively compared to the use of conventional soil fill. Also, the results from the analyses revealed that box structures with geofoam as filling materials reduced the earth pressure. The geofoam as fill material does not influence the bending moment values of the box sections beyond a fill height of 8 m.

Cross-Section Deformation and Bending Moment of a Steel Square Tubular Section.

When bending thin-walled profiles, significant distortion of the cross-section occurs, which has a significant impact on the course of the bending moment characteristics and on the value of allowable bending curvatures. This paper presents the results of experimental and numerical modeling of the box profile bending process, which was carried out in order to determine the dependence of the cross-sectional shape and bending moment of bending curvature. Extensive numerical calculations were used to model the process of shaping a square pipe from a circular tube and to model the bending process, especially when taking into account the effects of such a deformation path. The pure bending moment characteristics and the deformation of the cross-section were performed for a 25 × 25 × 2 mm square tube made of S235JR structural steel. The innovative approach for determining the parameters of cold bending square tubes pertained to considering the stress state in the preserved material in individual areas of their cross-section. The results of numerical modeling—after considering the history of deformation (i.e., the process of forming a square pipe from a pipe with a circular cross-section)—gave a satisfactory agreement with the results of experimental tests, both in terms of the degree of pipe wall deflection and the characteristics of the bending moment.

Flexural responses of nanobeams with coupled effects of nonlocality and surface energy

AbstractThis paper proposes a beam model with inclusion of surface and nonlocal effects. Beam‐bulk kinematics is formulated within the framework of Euler‐Bernoulli beam theory; Eringen nonlocal elasticity theory is employed to account for long‐range atomic interactions of a nanoscale beam; and Gurtin‐Murdoch surface elasticity theory is used to represent the size‐dependent effect inherent to a nanoscale beam. Surface‐layer balance equation between the surface and bulk stresses is treated in a consistent manner. Virtual displacement principle is exploited to consistently derive the governing differential equilibrium equation as well as the natural boundary conditions of the problem. The general form of beam bending solution is presented. Two numerical simulations employing the proposed beam model are conducted to study characteristics and behaviors of the nanobeam with various model parameters. The first simulation investigates the coupled effects of nonlocality and surface energy on transverse displacement and bending moment characteristics of nanowires under various support conditions. The second examines the influences of several model parameters as well as the size‐dependent effect on the effective bulk Young's modulus of the nanobeam.

Bending Moment Characteristics of Hard Roof before First Breaking of Roof Beam Considering Coal Seam Hardening

The mechanical properties of a coal seam affect the distribution of support pressure. Considering the strain hardening effect of coal seam, the support pressure relationship of three zones—softened, hardened, and elastic—of a coal seam with regard to a hard roof is proposed, and methods to determine an approximate expression for the support pressure of hardened zone of coal seam, the range of hardened zone, and the corresponding peak values of support pressure are provided. The deflection equations of a hard roof under three different support pressure relationships of coal seam before the first breaking were theoretically derived, and all the relevant integration constants were determined. Numerical examples of two cases are provided for calculating the bending moment of a hard roof and the support pressure of a coal seam. The analysis shows that as the working face advances, the maximum support pressure increases, the residual strength of coal seam at coal wall decreases, the overall deflection of roof gradually increases, the maximum bending moment of roof in the front of coal wall increases, and the advanced distance of roof bending moment peak gradually increases. As the depth of softened zone of coal seam increases, the similar conclusion is obtained, and the advanced distance of the roof bending moment peak increases at a relatively fast speed. Because the bending moment peak of hard roof is located near the support pressure peak in the softened zone of coal seam, the depth of softened zone of coal seam significantly affects the advanced distance of the bending moment peak of a roof. The actual advanced fracture distances of hard roof are distributed in a relatively broad range. The results indicate that there is a “large and long” type advanced fracture distance occurring in the actual stope. With the same overlying load and stope parameter conditions, the maximum support pressures of support roof in softened, hardened, and elastic zones considering a hardened coal seam are smaller than those in softened and elastic zones without hardening. However, the plumpness in front of the peak of the former support pressure curve is superior to that of the latter, and both the bending moment peak value and the advanced distance of bending moment peak of the former are higher than those of the latter.

Characteristics of the Bending Moment Acting on an Overhung Shaft in a Stirred Vessel

Abstract The bending moment acting on an overhung shaft in an impeller stirred vessel was measured using a moment sensor equipped with digital telemetry. The results show that the characteristics of bending moment, such as the mean amplitudes, the amplitude and frequency distributions and the intensity of the amplitude fluctuations are influenced by both the ratio of operational speed to resonant speed (n/nr) and the impeller type. Analysis of the bending moment amplitude shows that the dimensionless shaft bending moment decreases for low values of n/nr and increases with increasing n/nr for higher values of n/nr. The value of the n/nr transition point depends on the type of impeller used in the experiments. Analysis of the power spectral density of bending moment fluctuation shows that the main contributions to the bending moment for low impeller speeds (i.e. well below the first resonant frequency) come from factors related to the fluid flow while the impeller imbalance becomes steadily more dominant as the speed increases.

Effect of the impeller imbalance on the bending moment acting on a shaft in a stirred vessel

The bending moment acting on an overhung shaft equipped with an unbalanced impeller, as one of the results of the lateral Fluid-Structure Interactions (FSI) in stirred vessels, was measured using a moment sensor, equipped with digital telemetry. The results show that the imbalance of impeller has a considerable influence on the characteristics of bending moment, such as the mean amplitude and the intensity of amplitude fluctuation. Analysis of the amplitude distribution shows that the distribution is well fitted by a Weibull distribution, which tends to flatten and become more symmetrical about the mean as the imbalance increases. Further analysis of the bending moment power spectral density shows that the speed frequency of the bending moment, whose contribution to the bending moment fluctuation increases with the increasing imbalance, is caused by the imbalance of the stirring structure. These results can be applied to the mechanical design process for the shaft and the stirred vessel supporting it, and the manufacturing control of impeller balance quality.

Study on Eliminating the Effect of Bending Moment in Torque Measurement

The function characteristics of bending moment and torque were analyzed based on the principle of torque measurement and the adverse effect of bending moment to torque measurement was proved theoretically. By distributing the positions of resistance strain gauge on the transmission shaft and the relative positions in the bridge, an effective method of eliminating the adverse effect of bending moment was proposed base on the principle of superposition and counterbalance in the bridge, and the potential errors were analyzed and corrected. Then the proposed method was applied in measuring the torque of a motor shaft. The result shows that the effect of bending moment has been eliminated, and this method is feasible and effective.

풍력발전기 증속기에 전달되는 풍하중 변동특성 연구

본 논문은 정상풍속과 돌발풍속을 수학적으로 모델링하고 풍향에 따라 전달되는 메인축에서의 전달모멘트를 조사하여 기어박스에 전달되는 풍하중의 특성을 파악하였다. 정상풍속은 지상에서 고도가 높아짐에 따라 속도가 증가하게 설정을 하였다. 풍하중에 의해서 메인축으로 전달되는 모멘트의 평균값과 하모닉값을 풍향 입사각을 -45° ~ 45°로 변화를 주며 특성을 파악하였다. 또한 기어 트레인의 미스얼라인먼트를 유발시키는 굽힘 모멘트의 특성을 파악하였다. 정상풍속모델에서는 블레이드의 3배수 주파수(3X)로 하는 토크의 가진이 생기며, 바람의 방향이 +22.5° 일 때 수평방향의 굽힘 모멘트가 주축으로 들어가는 토크의 50%수준으로 발생하는데 이는 수평방향으로의 탄성 축 휘임을 유발하여 치가 모서리에서 물림이 발생하게 하는 원인을 제공함을 알 수 있었다. 돌발풍속의 경우, 3X, 6X, 9X를 가진주파수로 하는 토크의 가진이 바람의 방향이 +방향으로 커질수록 하모닉항의 상대 비율이 증가하였다.

Bending Moment Characteristics on Repeated Folding Motion of Coated Paperboard Scored by Round-Edge Knife

This work deals the creasing characteristics of coated paperboard. It was not clarified to estimate the deformation behavior of creased line from the first peak bending moment Mp1 and the initial gradient C1 of bending moment. In this study, a new prototype testing apparatus has been developed for seeking the bending moment and the side view picture of creased part during repeated folding motion. The permanent (residual) deformation angles, the variance of residual stiffness and the hysteresis characteristics of bending moment were analyzed for the nominal shear strain (the scoring depth) γ . The obtained results were as follows: (1) C1 was characterized with γ, while the second term gradient C2 was characterized with γ and the inverse of tracking angle Θ-1. (2) By introducing the area of closed curve of second term hysteresis ACC, it is revealed that the gradient of ACC was remarkably varied with Θ at near the peak point Mp1.

RESISTANCE MECHANISM OF NON-SLIP-TYPE EXPOSED COLUMN-BASE UNDER TENSILE VARIALBE AXIAL-FORCE

An experimental study on non-slip-type exposed column bases proposed by the authors, subjected to both cyclic horizontal laodings and variable axial forces in the limits of compression was carried out to make bending moment characteristics of the column bases and to propose models of restoring force characteristics. In addition, the same experiments on conventional exposed column base were conducted to show the effectiveness of the proposed column bases. The following conclusions were drawn from the experimental results:1) The restoring force characteristics of the non-slip-type column bases become linear-from-origin-type under variable axial forces, and the column bases sustain the self-centering performance reducing residual deformation of a building after an earthquake. 2) The energy absorption capability of the proposed column bases is higher than the conventional ones, and the energy absorption capacity is almost the same under between constant and variable axial forces. 3) The gap between the edge of the base plate and the foundation of the proposed column base under variable axial forces in tension and compression becomes smaller than the conventional one. 4) The gap between the base plate and the foundation of the proposed column base is not generated unless the axial force exceeds half of yield strength of all the anchor-bolts, therefore the bending resistance of the column base is not reduced by the shearing resistance of the anchor-bolt in the case of the lift-off of the column base.

Effect of crease depth and crease deviation on folding deformation characteristics of coated paperboard

Paperboard die cutting, which includes creasing, is a production technique widely spread in many fields such as foods, stationery packaging. For the improvement of productivity or the improvement of quality on die cutting, the estimation of endurance on die tools and the estimation of material properties on paperboard are required. Creasing is one of most important mechanical behavior for paperboard die cutting. This paper reports on a fundamental deformation behavior and fracture modes as delamination patterns of coated paperboard creased. The creasing characteristics were investigated by varying the crease depth and the lateral deviation of rule clearance. By reviewing the bending moment resistance and by observing the delamination process of creased part under a folding test, the variance of bending moment characteristics of creased part was discussed. Furthermore, by adding the lateral deviation of rule clearance, the correlation between the moving direction of the folding point and the non-symmetrically delaminated zones was also investigated.

Influence Functions of Bending Moment of Bevel Gear and Approximate Equations.

Before the calculation of the load distribution on the line of contact and the tooth root stress of a bevel gear under tooth end bearing, the tooth root stress due to the concentrated load was calculated by means of the three-dimensional finite-element method (FEM). With the results by FEM, the approximate equations for the influence functions for bending moment of bevel gear tooth were derived. Furthermore, the effects of the number of teeth and the gear ratio on the characteristics of bending moment were clarified.

RELIABILITY ANALYSIS OF A CONTINUOUS TWO-SPAN BRIDGE GIRDER

In this study, the reliability of continuous two-span bridge girder subjected to random vehicular loads is analyzed in the space domain as well as in the time domain. First, by the use of the results of the statistical analysis of randomly space-varying vehicular loads which have been already reported by the authors, the probabilistic characteristics of bending moment and the reliability of bridge girder in the space domain are analytically evaluated. Second, the distribution of the maximum bending moments for the lifetime domain are evaluated. The design values of bending moment are calculated for prescribed values of failure probability of girder bridge.