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• A dynamic theory of the HMS curved rod under 3D large deformation is presented. • The "tension-bending" and "shear-torsion" coupling effects of curved rod emerge in our model. • The finite element formulation and exact linearization of the dynamical problem are obtained. • An implementation based on Newmark algorithm and some numerical examples are presented. • Several experiments about a quarter arc HMS robotic arm are presented. Magnetorheological elastomers are active materials which can be actuated by the applied magnetic field. Hard magnetic soft (HMS) materials, a type of magnetorheological elastomers, show great potential in the fields of biomedical engineering and soft robotics, due to their short response time, remote operation, and shape programmability. To exploit its potential, a series of theoretical frameworks of HMS rods have been developed, but they are mainly limited to the static rod models or classical curved rod models that fail to consider the effect of the "initial curvature" on the distribution of the stress. In this work, we develop a curved rod theory to predict the 3D dynamic motion of the rod-like HMS robotics under large deformation. Based on the geometrically exact rod theory, we include the heterogeneous initial length of the longitudinal fiber caused by "initial curvature" into our model and obtain the reduced balance equations of the HMS robotics. As a result, the "tension-bending" and "shear-torsion" coupling effects of curved rods emerge in the present model. A numerical implementation of our model based on the classical Newmark algorithm is presented. To validate our model, three numerical examples, including the dynamic snap-through behavior of a bistable arch, are performed and compared with the simulation or experiment results reported in literatures, which show a good agreement. Finally, we experimentally study the 2D and 3D static and dynamic motion of a quarter arc HMS robotic arm under an applied magnetic field of 10 mT, and our model gives a satisfactory prediction, especially for static deformation. [ABSTRACT FROM AUTHOR]

The shape design of arch dams requires consideration of multiple complex factors, such as the shape of the valley at the dam site, engineering geological conditions, regional seismic intensity, hub layout, and flood discharge methods. Therefore, the shape design of arch dams is a typical complex optimization problem. In this paper, a general parametric design method of arch dam shape is proposed, which can describe all kinds of arch dams such as parabola and hyperbola. By fixing the position of the arch end and adjusting the position, shape, and thickness of the arch crown beam to drive the shape change of the arch dam, automatic modeling and finite element stress deformation calculation of the arch dam are achieved. Taking the minimum volume of the arch dam as the optimization objective, intelligent optimization of the arch dam shape is carried out under constraints such as geometry, stress, and stability. Using this method to optimize the shape of a high arch dam, the optimization efficiency is high and the optimization effect is obvious. The stress of the optimized arch dam body and the equivalent stress of the foundation surface meet the requirements of the specifications, and the flexibility coefficient and stress level also meet the indicators recommended by experience. [ABSTRACT FROM AUTHOR]

At present, the large-span porous steel corrugated plate arch culvert reinforced with composite beams of concretesteel corrugated plate (referred to as "concrete ring") has been preliminarily applied in actual projects. However, the force anddeformation characteristics in the construction process have not been studied in depth. This paper combines the in-situ test ofa9 m span steel corrugated plate arch culvert with 4 holes to monitor the mechanical behaviour of the concrete ring and the steelcorrugated plate, establish a refined finite element model, compare the force and deformation characteristics of the structure indifferent sections, and study the influence of the concrete ring on the structure. The results show that: 1) different arch spansand the presence or absence of the concrete ring have little effect on the deformation of arch culverts; 2) in the backfilling ofthe arch, the stress of the steel corrugated plate and rebar of the side span are greater than the corresponding position of themiddle span, and the maximum difference is 47.26 MPa and 49.75 MPa, respectively; 3) the concrete ring can significantlyreduce the stress of the steel corrugated plate, which is about 10% of its design strength. [ABSTRACT FROM AUTHOR]

The Partially Concrete Filled Steel Tube (PCFST) structure has gradually been applied to bridges as the main load carrying components in recent years, owing to the advantages of light weight and high stability. The failure mechanism and load carrying capacity of PCFST structure highly depends on the concrete filling ratio. For this purpose, the failure mechanism and parametric analysis of a single arched PCFST cable stayed bridge tower are investigated by using both refined solid element simulation and quasi-static experiment. The results shows that the PCFST arched tower experiences asymmetrical instability failure subjected to quarter span symmetrical loading, and the plastic hinges appears firstly at the tower arch closely above the tower columns, and then the bottom of the tower columns, forming a rotating mechanism leading to the instability failure. Filling concrete or not will result in two opposite deforming propagations of the plastic hinges, and when the concrete filling length exceeds the length of plastic hinge, the initial rigidity and ultimate load carrying capacity of the PCFST structure will sharply increase. Finally, according to the results of the extended parametric analysis based on the real size simulation, an improved initial stress reduction coefficient of PCFST structure is then suggested. [ABSTRACT FROM AUTHOR]

In underground spaces, corrugated steel plate (CSP) pipe-arches may experience local buckling instability, which can subsequently lead to the failure of the entire structure. Recently, sandwich CSP pipe-arches have been used to enhance the stability of embedded engineering outcomes, and their buckling behaviors require in-depth research. In this paper, we establish a theoretical model by simplifying soil support and using Hoff sandwich plate theory to focus on the local buckling stability of the straight segment in embedded sandwich CSP pipe-arches using the Rayleigh–Ritz method. Through stability analysis, the instability criteria for embedded sandwich CSP pipe-arches are analytically determined. Numerical calculations reveal that the critical buckling load of a sandwich CSP pipe-arch is affected by several factors, including the elastic modulus, thickness, Poisson's ratio, rotational constraint stiffness, and the length of the straight segment. Specifically, increasing the thickness of the sandwich CSP pipe-arch can substantially enhance the critical buckling load. Meanwhile, the wavenumber is affected by the elastic modulus and the length of the straight segment. The analytical results are in agreement with those obtained from finite element analysis. These findings provide a theoretical basis and guidance for the application of sandwich CSP pipe-arches in fields such as subway stations, tunnel construction, underground passages, and underground parking facilities. [ABSTRACT FROM AUTHOR]

This paper outlines the planning of a bridge in central Germany. Scheduled for construction in mid‐2024, this new bridge is a replacement for a century‐old pedestrian bridge crossing the Lahn river. The proposed bridge will be an airtight‐welded arch bridge, employing steel cross‐sections in both the arch and tension member. Designed as a single‐span, the arches extend 48.0m over the Lahn. The two arches have a flat rise of 4.65m, supporting the roadway through 9 inclined flat steel hangers. This paper delves into the structural engineering aspects, exploring challenges inherent in the design process. An examination of the parametric design process, facilitated through 3‐D modeling in Rhino® and Grasshopper®, will be presented, along with insights into their interface with the finite element modeling software, RFEM®. This process enables an engineering approach to form‐finding and structure optimisation through iterative design checks for various elements and stages of the structural analysis. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Explosives & Propellants is the property of Chinese Journal of Explosives & Propellants Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of South China University of Technology (Natural Science Edition) is the property of South China University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Arch and serpentine structures are two fundamental structural forms with significant applications in various fields. When subjected to compressive loading at both ends, these structures undergo flexural-torsional post-buckling, resulting in complex deformation modes that are challenging to describe using basic functions (e.g., trigonometric functions and polynomial functions), posing significant challenges in finding analytical solutions. In this study, we propose a novel approach to address this issue. By representing the lateral displacement with a trigonometric series expansion and utilizing the equilibrium equation, the angular displacement is expressed in terms of special functions known as Mathieu functions. Furthermore, the energy method is employed to obtain analytical solutions for the flexural-torsional post-buckling deformation components. The theoretical findings are validated through experiments and finite element analysis. Based on the theoretical results, explicit analytical expressions for the maximum principal strain and the bending-torsion ratio of the structures are derived, offering valuable insights for the design of arch and serpentine structures in practical applications. [ABSTRACT FROM AUTHOR]

This study aims to analyze the in-plane free vibrations of arches comprising the laterally symmetric functionally graded materials. Emphasis is placed on the circular arch whose material properties vary laterally symmetrically about the centroidal axis by a power-law function. The differential equations governing the mode shape of the arch were derived under the boundary conditions and were numerically solved to calculate the natural frequencies using the Runge–Kutta and Regula–Falsi methods. Calculation results of this study for natural frequencies compare well with those of the finite element method. The effects of various arch parameters on natural frequencies are highlighted and discussed in detail. [ABSTRACT FROM AUTHOR]

This study aims to analyze the free vibration of an ogival arch in which two symmetrical arched shapes are discontinuously met at the mid-arc. Differential equations governing the free vibration of an ogival circular arch were derived, where the rotatory inertia and shear deformation effects are included. The governing equations were numerically solved to calculate natural frequencies and mode shapes. In numerical solution methods, the symmetric and anti-symmetric boundary conditions at the mid-arc were focused rather than the boundary conditions of supported end due to the discontinuity of the mid-arc. For the first time, the free vibration problem for discontinuous arches, such as ogival arches, is solved in this study. Calculation results of this study for natural frequencies are compared well with those of the finite element method. The effects of various arch parameters on natural frequencies were highlighted and discussed in detail. [ABSTRACT FROM AUTHOR]

In the health monitoring work of long‐span concrete‐filled steel tube tied arch bridges, finite element models have been commonly employed to indicate the practical stress state, and providing accurate data in real time and efficiently has been confirmed as the weakness of the finite element model. The prediction model is built in accordance with the general regression neural network (GRNN), and the parameters of the GRNN model are optimized using particle swarm optimization (PSO) to build the PSO‐GRNN prediction model, with the aim of modifying the finite element model. A finite element analysis model is built using the Qiuhuli flying‐swallow‐typed tied arch bridge to verify the effect of the PSO‐GRNN prediction model. The model test data are acquired using the horizontal thrust of arch foot, the bulk weight of main beam, and the tension of tied rod as the input variables and using the stress of main arch rib steel pipe, the stress of main arch concrete, and the displacement of mid span as the output variables. As revealed by the results, the average prediction accuracy of the PSO‐GRNN model constructed in this article is 96.706%, 98.531%, and 99.634%, respectively, which are 1.980%, 1.706%, and 0.40% higher than the back propagation (BP) neural network model and 2.262%, 1.632%, and 0.387% higher than the GRNN model. The mean absolute percent error (MAPE), root mean square error (RMSE), coefficient of determination (R2), and Nash‐Sutcliffe efficiency (NSE) coefficient were used to evaluate the prediction performance of the model. The PSO‐GRNN model has the highest fitting accuracy, indicating that the established PSO‐GRNN prediction model can more effectively predict the relevant parameters of concrete‐filled steel tube tied arch bridges and has high accuracy. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Beijing University of Civil Engineering & Architecture is the property of Journal of Beijing University of Civil Engineering & Architecture Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Changjinghuang Railway Xinjiang Xizhi Bridge is a (90 + 180 + 90) m continuous beam arch bridge, and the arch rib steel pipe installation adopts "short bracket assembly and overall lifting method". In order to ensure the accuracy of closure, the stress and deformation of the arch rib and bracket must be strictly controlled. Midas Civil is used to establish the finite element model to simulate the overall lifting construction process of the arch rib. Based on the model, the stress and deformation of the arch rib and the supports are analyzed, and the determination method of the horizontal cable force under temperature variations is proposed. The results show that the stress and deformation of the arch rib and bracket meet the requirements. Considering the variation of temperature, the tension force of the horizontal cables is taken as 200 t. The construction plan proposed under the guidance of numerical calculation results has been proven by practical engineering to meet the requirement of closure accuracy, which can be used as a reference for similar projects. [ABSTRACT FROM AUTHOR]

Underground excavation is usually accompanied by complex soil-structure interaction problems in practical engineering. This paper develops a novel multi-scale approach for investigating the soil arching effect through trapdoor tests. This approach adopts the finite element method (FEM) and smoothed particle hydrodynamics (SPH) method to handle the particle-rigid body interaction in the trapdoor tests, incorporating a micromechanical 3D-H model to derive the nonlinear material response required by the SPH method. The variation of the earth pressure on the trapdoor in simulations exhibits good agreement with those of the experiments. Extensive parametric analyzes are performed to assess the effects of soil height and inter-particle friction angle on the evolution of load transfer and soil deformation. Three deformation patterns are observed under different buried conditions, including the trapezoid, the triangle, and the equal settlement pattern. Results indicate that the planes of equal settlement develop progressively with the trapdoor movement and then enter the range of experimentally observed values. Additionally, three failure mechanisms are identified that correspond to the three deformation patterns. Due to the advantages of the micromechanical model, mesoscale behavior is captured. The anisotropy of stress distribution in the plastic region is found during the arching process. [ABSTRACT FROM AUTHOR]

When solving nonlinear algebraic equations that arise from discretization using the finite element method (FEM), it is often observed that the standard Newton-Raphson (N-R) iteration either fails to converge or necessitates a large number of iterations in the vicinity of critical points. This work proposes an additional numerical strategy, known as the Potra-Pták iterative cycle, to improve the efficiency of solving highly nonlinear structural problems. Therefore, the focus here is on making the nonlinear solver more robust and efficient, allowing the analysis of more complex nonlinear structures. In the Potra-Pták iterative cycle, two corrections of the objective function (energy function) are performed. The introduction of a second correction in the iterative cycle makes the Potra-Pták strategy more efficient than the standard or modified N-R iterations. This numerical strategy was implemented in the homemade Computational System for Advanced Structural Analysis (CS-ASA) program. The program is based on the FEM and is capable of performing static and dynamic nonlinear analysis of steel, concrete, and composite structures, and its efficiency is then verified through the analysis of slender frames and arches. The algorithm details for solving the nonlinear structural problem, characterized by the Potra-Pták scheme, are provided. [ABSTRACT FROM AUTHOR]

Compared with circular, arched, and pipe-arched soil–steel structures, box-type soil–steel structures (BTSSSs) have the advantages of high cross-section utilization and low cover depth. However, the degree of influence of the crown and haunch radii on the mechanical performance of BTSSSs is still unclear. Therefore, two full-scale BTSSS models with a span of 6.6 m and a rise of 3.7 m but with different crown and haunch radii were established, and the mechanical properties during backfilling and under live load were tested. Afterward, 2D finite element models (FEMs) were established using the ABAQUS 2020 software and verified using the test data. The influence of cross-section geometric parameters on mechanical performance was analyzed by using the FEM, and a more accurate formula for calculating the bending moment during backfilling was proposed. The results show that the BTSSS with a smaller crown radius has a stronger soil–steel interaction, which promotes more uniform stress on the structure and makes the structure have smaller relative deformations, bending moments, and earth pressure. The span and arch height greatly influence the bending moment and deformation of the structure. Based on the CHBDC, the crown and haunch radii were included in the revised calculation formula. [ABSTRACT FROM AUTHOR]

Summary: This work proposes a higher‐order unified shell finite element for the analysis of cylinders made of compressible and nearly incompressible hyperelastic materials. The nonlinear governing equations are derived employing the Carrera unified formulation (CUF), thanks to which it is possible to build shell elements with the capability to capture three‐dimensional (3D) transverse and out‐of‐plane effects. The material and geometric nonlinearities are expressed in an orthogonal curvilinear reference system and the coupled formulation of hyperelastic constitutive law is considered. The principle of virtual work and a total Lagrangian approach is used to derive the nonlinear governing equations, which are solved by a Newton–Raphson scheme. The numerical investigations deal with a curved arch and both thick and thin cylinders subjected to line and point loadings. The obtained results are validated by comparing them with those from the literature. They demonstrate the reliability of the proposed method to analyze compressible and incompressible hyperelastic shell structures. [ABSTRACT FROM AUTHOR]

Due to their excellent thermal conductivity and sensitivity to temperature changes, special attention should be paid to the influence of temperature on steel-structure bridges. The temperature effect is complex, especially for unstable steel arch bridges with complex structural forms. This paper proposes an approximate method that measures the three-dimensional temperature field of the symmetrical arch rib with the two-dimensional temperature field of multiple sections. In addition, it converts the complex radiant intensity calculation of the special-shaped steel box arch rib into the calculation of numerous planar radiant intensities. It uses the ANSYS Workbench to establish the three-dimensional transient thermal analysis finite element model of the No. 2 steel box arch rib. The influence of seasons and arch rib direction on the temperature field of steel box arch ribs and the stress and deformation of steel box arch ribs under non-linear temperature effects were analyzed. The results show that the temperature changes in different seasons significantly impact the temperature changes in the arch ribs. The change in the azimuth angle of the arch rib has a significant impact on the temperature difference between the web plates on both sides of the arch rib; under the influence of the temperature field at the most unfavorable time in summer and winter, symmetrical stress concentration occurs in the arch foot area. Furthermore, the maximum vertical displacement is 13.9 mm and 10.8 mm, respectively. Finally, when the angle is 40°, the maximum temperature difference between the web plates on both sides is 6.9 °C. [ABSTRACT FROM AUTHOR]

In order to study the ultimate span of a concrete-filled steel tube (CFST) arch bridge, taking the structural strength, stiffness, and stability as the limiting conditions, the finite element analysis method is adopted to carry out research on the influence law of a single parameter of the pipe diameter, wall thickness, and cross-section height on the ultimate span of the arch axial shape. The result is used as a sample point to determine the ultimate span of the CFST arch bridge under multifactor coupling based on the response surface method. The finite element method is used to check the strength, stiffness, stability, number of segments and maximum lifting weight, steel content rate, and steel pipe concrete constraint effect coefficient of the CFST arch bridge under the ultimate span diameter. The results show that, when analyzed using a single parameter, the ultimate span diameter of the CFST arch bridge increases with the increase in the steel pipe diameter and the cross-section height, and then decreases. Moreover, it increases with the increase in the wall thickness of the steel pipe, and the CFST arch bridge reaches the ultimate span with the increase in the steel pipe wall thickness. When the pipe diameter is 1.38 m, the CFST arch bridge reaches the ultimate span; according to a multi-parameter coupling analysis, when the pipe diameter is 1.49 m, wall thickness is 37 mm, and cross-section height is 17 m, the CFST arch bridge reaches the ultimate span of 821 m, which meets all of the limiting conditions, and, at this point, the arch axial coefficient is 1.2. The results of the finite element calculation show that the structural strength, prior to the stiffness, stability, and other limitations, just reaches the critical value of the limiting conditions. [ABSTRACT FROM AUTHOR]

This article presents a sophisticated approach to updating the finite element model of two historical arch masonry bridges located in the challenging terrain of Kalka Shimla mountain railway, using vibration testing results. To estimate the dynamic characteristics of the bridges, ambient vibration testing was carried out. Next, initial finite element models of the bridges were developed based on geometrical survey data. Sensitivity analysis was used to determine which parameters needed to be modified for the bridges. The response surface method and global optimization techniques were employed to identify the optimal values of structural parameters that would result in a satisfactory agreement between the numerical and measured natural frequencies of the heritage bridges. Ultimately, the methodology provided a surrogate mathematical model to represent the relationship between structural parameters and dynamic response, and could predict the damage status of the historical bridges. [ABSTRACT FROM AUTHOR]

Purpose: This study investigates the uncertain eigenvalue analysis of graded porous and sandwich arches, considering material stochasticity, using an efficient perturbation-based stochastic finite element approach founded on the three-nodded element. Internal pores in the graded porous arch follow three distinct types of distribution: type 1, type 2, and type 3. The mechanical properties of a graded porous arch change in the thickness direction. Method: The present stochastic finite element formulation is based on higher order shear deformation theory in conjunction with the probabilistic first-order perturbation technique (FOPT). Results: The present model is validated using limited results from the literature as well as independently developed Monte Carlo simulation (MCS) results. The impacts of various influencing parameters such as opening angle (θo), porosity distribution type, the thickness-to-length ratio (h/L), and porosity coefficient (eo) on the uncertain eigenvalue analysis of the graded porous and sandwich arches have been investigated in the parametric study. Conclusion: It is found that the SD/Mean of the frequency of the graded porous arch is more susceptible to distribution type 3. [ABSTRACT FROM AUTHOR]

Copyright of Firat University Journal of Experimental & Computational Engineering (FUJECE) is the property of Firat University Journal of Experimental & Computational Engineering (FUJECE) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND: In the treatment of edentulous maxillary implants supported fixed repair, the selection of upper scaffold structure materials and the design of different distal implant implantation methods have a close influence on the long-term stability of the whole mouth implant repair. OBJECTIVE: To comprehensively explore the influence of three different materials of upper scaffold and two implant fixation designs on the biomechanics of the fixed maxillary implant repair based on the three-dimensional finite element method. METHODS: Based on the conical beam CT data of a healthy adult with normal jaws, the Mimics software was used to separate the maxillary and maxillary dentin three-dimensional solid models, and the Geomagic Studio software was used to construct the three-dimensional finite element model of denture with denture implant and fixed maxillary arch combined with specific model parameters. According to the different designs of distal implants in the maxillary posterior region, two scheme models were established. Scheme 1 (Design 1) was designed in accordance with the “All-on-4” design used in clinical practice. Two implants were vertically implanted in the bilateral incisor region of the maxilla, and the other two implants were implanted in the bilateral second premolar region at a 30° angle. In scheme 2 (Design 2), two implants were vertically implanted in the lateral incisor region of the maxilla, and two short implants were vertically implanted in the posterior region of the maxilla in the bilateral second premolar region. Three materials (titanium, zirconia and polyether ether ketone) were used to assign values to the upper scaffold structure in the two designs, and six different models were obtained. The biomechanical effects of the implant, surrounding bone tissue and the upper scaffold structure were compared and analyzed in the oblique loading direction. RESULTS AND CONCLUSION: (1) The maximum stress peaks of all models were distributed in the neck region around the posterior implant and the cortical bone under the two edentulous implant fixed restoration schemes, regardless of the material of the upper scaffold. (2) Compared with the alternative design of Design 2, which adopted vertical implantation of short implants, Design 1 showed a more ideal stress distribution on the maxilla. (3) The scaffold model constructed by polyether ether ketone material transferred higher stress to the implant and surrounding bone tissue close to the loading zone of the upper jaw bone, followed by titanium and zirconia. As for the support itself, the peak stress of the upper scaffold of polyether ether ketone was significantly lower than that of the zirconia and titanium scaffolds. Zirconia scaffolds were used among the three upper scaffolds to disperse the stress distribution of implant and bone tissue. (4) The results suggest that both designs can be applied to clinical practice. However, from the perspective of biomechanics, the stress distribution of the implant, surrounding bone tissue and upper scaffold in Design 1 is more rational, which is more conducive to the long-term prognosis of fixed implant repair in patients with edentulous jaws. The upper scaffold material has a certain influence on the stress distribution of the implant-bone interface. [ABSTRACT FROM AUTHOR]

The objective of this study was to examine how various anchorage methods impact long-term maxillary whole arch distalization using clear aligners (CAs) through an automated staging simulation. Three different anchorage reinforcement methods, namely, Class II elastics, buccal temporary anchorage device (TAD), and palatal TAD, were designed. Orthodontic tooth movement induced by orthodontic forces was simulated using an iterative computation method. Additionally, the automatic adjustment of the CA was simulated through the application of the thermal expansion method. The results indicated that the palatal TAD group had the largest retraction of incisors, followed by the buccal TAD group and the Class II elastic group, while the least was in the control group. The largest distal displacements and efficiency of molar distalization for the first and the second molars were noticed in the palatal TAD group. Arch width increased at the molar and premolar levels in all groups. The FEM results suggested palatal TAD had the best performance considering anterior teeth anchorage maintenance, both sagittally and vertically. However, attention should be paid to the possible increasement of arch width. [ABSTRACT FROM AUTHOR]

The arched cellular beam has the advantages of both the solid-web arch and the straight beam with web opening, and has become increasingly admired by architects in recent years. In this paper, four arched cellular beam specimens are designed using an orthogonal test method (OTM) with a three-factor and two-level approach. Firstly, the static loading test is carried out to analyze the mechanical response of the arched cellular beam under concentrated load. Then, a numerical analysis based on ABAQUS finite element (FE) software is carried out. The results show that the simulation results agree well with the test results, which indicates the accuracy of the simulation analysis method. Finally, the buckling load of the arched cellular beam under three different loads is calculated using the variable parameter FE analysis. Combined with the range analysis in the OTM, the influence of the target factor on the buckling load of the arched cellular beam is determined. The results show that the order of the factors affecting the out-of-plane elastic buckling is rise–span ratio > web height–thickness ratio > diameter–depth ratio. [ABSTRACT FROM AUTHOR]

In order to study the mechanical bearing behavior of arched sandwich roof structures, a full combination and independent action mode of concrete sandwich composite panels was constructed using the finite element method, and an arched steel–concrete composite sandwich roof with a span of 18 m was subjected to a numerical simulation test under a full-span vertical uniformly distributed load, with the bearing characteristics of the arched sandwich roof discussed in depth. The results show that the cross-sections of l/16 and l/2 of the elliptical arch sandwich roof are weak sections, and the tensile cracking of concrete appears for the first time in the upper and lower wythes of the elliptical arch sandwich roof, the von Mises stress level of the lower wythe of the l/16 section is higher under the ultimate load, and the roof shows four-part form failure characteristics. With the expansion of the cracking range of the upper and lower concrete wythes of the steel–concrete composite sandwich arch roof, the load–displacement curve of the roof structure does not decrease significantly, and the bearing capacity of the structure is high and the vertical deformation is small. The steel–concrete composite segment at the end of the roof effectively strengthens the edge constraint of the roof and improves the integrity of the sandwich roof. The upper and lower concrete wythes of the sandwich roof show a fully combined action mode in the elastic working stage and, when the concrete cracks, it shows a partial combined action mode. [ABSTRACT FROM AUTHOR]

The service performance of tunnel lining is affected by crack properties and development states. In this paper, numerical simulation models were established to investigate the mechanics characteristics and safety performance for lining structures under different cracks based on the extended finite element method (XFEM). Analyze multiple quantitative factors in simulation, including changes in crack location, crack length, and crack distribution range in the lining structure. The axial force and bending moment of the preset cracks in the lining structures were first studied. The maximum safety factor attenuation rate ( D k m a x ) was proposed to analyze the impact of longitudinal and annular cracks on the safety performance. The axial force at the vault of the lining arch is the most significantly affected by the combined longitudinal cracks at multiple locations. When the length of a longitudinal crack increases from 1 m to 6 m, the axial force value at the crack point decreases by 33.77%, 36.15%, and 11.32%. However, the bending moment value increases by 4.47 times, 2.50 times, and 1.69 times. Under the influence of longitudinal cracks in an "arch crown + arch shoulder", "arch crown + arch waist", and "arch crown + arch shoulder + arch waist", the axial force in the arch vault increased by 21.55%, decreased by 17.52%, and decreased by 13.45%. The distribution pattern of the bending moment under the influence of circumferential cracks shows convexity at the arch shoulder and arch foot, and concavity at the arch waist and side walls. The safety factor scatter curve with longitudinal cracks shows a gradual transition from a "W" shape to a "U" shape. The safety factor curve with circumferential cracks presents an approximately symmetrical wave-shaped distribution. [ABSTRACT FROM AUTHOR]

There is no analytical solution to the deflection influence line of catenary hingeless arches nor an explicit solution to the deflection influence line difference curvature of variable section hingeless arches. Based on the force method equation, a deflection influence line analytical solution at any location before and after structural damage is obtained, and then an explicit solution of the deflection influence line difference curvature of the structural damage is obtained. The indexes suitable for arch structure damage identification are presented. Based on analytical theory and a finite element model, the feasibility of identifying damage at a single location and multiple locations of an arch bridge is verified. This research shows that when a moving load acts on a damaged area of an arch structure, the curvature of the deflection influence line difference will mutate, which proves theoretically that the deflection influence line difference curvature can be used for the damage identification of hingeless arch structures. This research has provided theoretical support for hingeless arch bridge design and evaluation. Combined with existing bridge monitoring methods, the new bridge damage identification method proposed in this paper has the potential to realize normal health status assessments of existing arch bridges in the future. [ABSTRACT FROM AUTHOR]

Geosynthetic reinforced and pile-supported (GRPS) provide an economic and effective solution for embankments. To investigate the load-bearing mechanism of the GRPS embankment in loess, experimental and numerical studies under static and dynamic loading are carried out. The characteristics of soil arch effect and tensile membrane effect of GPRS embankment under static and dynamic loading are revealed by analyzing pile–soil stress ratio, tension of geogrid, and stress distribution of pile. The test results show that the pile–soil stress ratio under dynamic loading is reduced by 2.3 compared with static loading. In comparison to static load, the soil arching effect is attenuated under dynamic load, and the stronger the static load soil arching effect, the greater the degree of weakening under dynamic load. In addition, under dynamic loading, the tensioned membrane effect is still effective, but its enhancement is not as pronounced as under static loading. Furthermore, by using the finite element software, the numerical model is developed and validated with the experimental results. The parameter analysis of the load-bearing performance of the GRPS embankment is accomplished using the finite element model as well. [ABSTRACT FROM AUTHOR]

The Loushui River Bridge is a mountainous long-span steel truss arch bridge with high and low arch seats. The design and construction of the bridge follow the principle of minimizing environmental damage and promoting sustainable development. In this article, the mechanical performance of this bridge is investigated experimentally and numerically at both the construction and operation stages. A series of validated finite element models were established for linear and nonlinear analyses by introducing geometric imperfections, geometric nonlinearities, and material nonlinearities. Then, several optimized models based on different types of design are compared with the original structure. The results indicate that the stability of the asymmetric bridge met the design requirements in both the construction and operation stages. However, the lateral stability and stiffness of the asymmetric bridge are weak due to the wind hazard that occurred in its mountain ravine. The out-of-plane instability from the short half-arch is the dominant failure mode, and the weakest area is where the arch ribs intersect with the bridge deck. It can be solved by adding more cross bracings without affecting the clearance above the bridge deck or by improving the material intensity of the arch. [ABSTRACT FROM AUTHOR]

The complex distribution of synchronous grouting pressure results in excessive tunnel deformation and various structural diseases, especially for ultra-large-diameter shield tunnels. In this study, to reduce the risk of tunnel failure, a three-dimensional refined finite element model was established for the Wuhan Lianghu highway tunnel project, taking into account the non-uniform distribution of synchronous grouting pressure. This study focuses on investigating the development patterns of internal forces, deformations, and damages in segment structures under varying grouting pressure ratios. The results indicate that the primary failure mode of a segment is tensile failure occurring at the outer edge of the arch. Moreover, an increased ratio of grouting pressure between the arch bottom and top leads to a higher positive bending moment value and greater tensile damage at the arch waist. The tunnel ring gradually exhibits distinct "horizontal duck egg" shape deformation. When the grouting pressure ratio is 2.8, there is a risk of tensile cracking at the outer edge of the arch waist. At this time, the segment convergence deformation is 39.71 mm, and the overall floating amount reaches 43.12 mm. This research offers engineering reference for the prediction of internal forces and deformations in ultra-large-diameter shield tunnels during grouting construction, thereby facilitating their application in the development of resilient cities. [ABSTRACT FROM AUTHOR]

In this study, the effect of the variation of the arch form in thickness and height on the bridge was investigated as a numerical analysis. For this purpose, the historic Antik Iscehisar Bridge located in the Iscehisar district of Afyonkarahisar in the Aegean Region was elected as a numerical application. The bridge was subjected to its own weight and moving load as a static analysis. For dynamic analysis, the effect of 10 different fault movements with historical character obtained from The Pacific Earthquake Engineering Research Center (PEER) on the bridge was investigated. The areas of principal stress and deformation resulting from the applied analyses were determined. Contour diagrams, tables, and charts were given in a comparative manner based on the results of the analysis applied to the bridge. At the end of the analysis, it was observed that the displacements decreased as the arch thickness increased under its own weight in the bridge. In addition, under the influence of live loads and earthquakes, it was observed that the displacements decrease as the arch thickness increases. A seismic reliability assessment was made using the performance criteria provided in this study. If the security level is below what it should be, reinforcement applications can be designed. Accordingly, future maintenance and monitoring planning can be made. [ABSTRACT FROM AUTHOR]

This work presents analytical solutions for thermoelastic behaviors of multilayer arches with temperature-dependent (TD) thermomechanical properties under thermomechanical loadings. The temperature is varied across the thickness of the arch. Firstly, an arched-slice model is developed, which divides every layer of the arch into numerous hypothetical arched slices with uniform thermomechanical properties. Based on the model, the nonlinear heat conduction equations across the thickness of the arch are solved using the iteration approach, and then the thermoelastic equations obtained from the two-dimensional thermoelasticity theory are solved using the state-space approach and transfer-matrix approach. The present solutions are compared with those obtained using the finite element method and the Euler–Bernoulli theory (EBT). It is found that the error of the EBT increases when the angle of the arch increases or the length-to-thickness ratio decreases. Finally, numerical examples are conducted to analyze the effects of surface temperature and TD thermomechanical properties on the temperature, displacement, and stress distributions of a sandwich arch. The results show that the temperature dependency of thermomechanical properties is a key parameter in predicting the thermoelastic behaviors of the arch in a high-temperature environment. [ABSTRACT FROM AUTHOR]

The Great Wall is one of the most famous cultural heritages in the world. The defensive forts constitute the most important parts of the Great Wall. However, many of them have been severely damaged through the centuries, and their status requires a scientific evaluation. Taking the part of the Great Wall in the Yanqing district with 101 defensive forts as an example, on-site investigations were carried out and the main architectural forms, as well as the damage characteristics, were detected. Based on the architectural form analysis, a hierarchical quantitative evaluation system of the structural safety for the hollow defensive forts was established under vertical load. The grading criteria of crack and displacement indexes were obtained by using the elastic-plastic damage model through the finite element method. The weights of each layer index were calculated with the component importance method and the Analytic Hierarchy Process method. The component importance of the defensive forts is ordered as stone stereobate > brick stereobate > brick arch > flank wall > crenellation. Finally, four representative hollow defensive forts were chosen to demonstrate the proposed quantitative evaluation method. The research results can provide a preliminary screening method for conservation prioritization of the Great Wall forts. [ABSTRACT FROM AUTHOR]

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 34.9 MPa, and on the lower edge, it was -60.4 MPa. The maximum deflection was -35.88 mm. The maximum stress in the guide beam occurred during the jacking process and was -53.2 MPa, corresponding to the crosssection at the root of the guide beam. The maximum deflection of the guide beam occurred in the maximum cantilever state and was -30.79 mm. During the arch rib jacking process, the maximum stress was -49.4 MPa. 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. [ABSTRACT FROM AUTHOR]

Doubly corrugated steel arches are made by pressing transverse corrugations on trapezoidal cold‐formed steel sheets. Several studies show that these transverse corrugations may have a significant detrimental effect on the stiffness and load‐bearing capacity of the original trapezoidal profile. This paper presents an experimental campaign aimed at investigating the effects of transverse corrugations on the behaviour of arches. The campaign includes reduced tests on flat sheets and sheets with a single corrugation, as well as full tests on arches with spans ranging from 10 to 20 m. Subsequently, a simplified design procedure based on nonlinear 2D beam finite element models is proposed. The models account for the transverse corrugation effects by using intermediate rotational springs and equivalent beam section areas, which are calibrated from the results of the reduced experiments. A brief sensitivity study of the finite element results with respect to different modelling factors is conducted, and the different effects of the corrugation assessed. Finally, the simplified finite element models are validated by comparing the experimental and numerical force‐displacement curves, which show reasonably good agreement. However, further research is needed to refine and extend the proposed procedure. [ABSTRACT FROM AUTHOR]

To study the evolution of stress on the ring and segment interfaces during the construction process of the concrete encapsulation of the main arch ring in a rigid-frame arch bridge, alongside its impact on the ultimate load-bearing capacity of the main arch ring, a 1:10 scale model experiment was conducted by taking the 600 m Tian'e Longtan Bridge as the prototype. The key cross-section concrete strain data were collected during the entire construction process of the main arch ring via fiber-optic strain sensors, which were used to investigate the stress evolution at ring and segment interfaces. ANSYS APDL was employed to simulate the ultimate bearing capacity under various loading conditions of two different finite element models, which were, respectively, formed segmentally and by single pouring. The results revealed that (1) after the closure of the concrete encapsulation of the main arch ring, the concrete stress in the cross-section exhibits significant stress disparities. At the same cross-section, the level of the web concrete stress can reach 76% of the floor concrete stress, while the roof concrete stress level is less than 20% of the floor concrete stress. (2) At the junction of two adjacent work planes, there are considerable differences in the stress levels of the concrete on both sides. After the closure of the main arch ring, the intersegment stress ratios of the floor, web, and roof concrete are 60~70%, 40~60%, and 0~5%, respectively. (3) Loading conditions remarkably affected the ultimate bearing capacity of the main arch ring. Under mid-span loading and 1/4 span symmetrical loading conditions, compared to single-pour concrete encapsulation, the ultimate bearing capacity of the main arch ring with concrete encapsulated by segmented and ring-divided pouring decreased by 19.16% and 5.23%, respectively, compared to single-pour concrete encapsulation. This suggests that the non-uniformity of stress distribution in the concrete sheath can lead to reductions in the ultimate bearing capacity of the arch ring. [ABSTRACT FROM AUTHOR]

A small clear-distance, double-arch tunnel under an asymmetrical load combines the characteristics of small clear-distance, tunnels and double-arch tunnels, and the influence of an asymmetrical terrain must be considered. Its construction stability is a problem worth studying. This paper used the Wengcun tunnel as the engineering background. Midas/GTS finite element analysis software was used to study the effects of eight excavation sequences and two excavation methods on tunnel stability. The results showed that the deformation and force of the tunnel were asymmetric under the asymmetrical terrain. Both middle partition walls were deformed towards the shallowly buried side, and the shallowly buried side was deformed to a greater extent. Excavating shallow side tunnels first can effectively mitigate the impact of asymmetric terrain. The arch settlement of the Center Diaphragm Excavation Method is 1.33 cm, which is smaller than the three-step excavation method of 1.48 cm; however, this difference is not significant. The Three-bench Excavation Method was more efficient. Based on the conclusion of a numerical simulation, the construction site adopted the construction sequence of excavating the shallowly buried side tunnel first and adjusted the excavation method to the Three-bench Excavation Method. [ABSTRACT FROM AUTHOR]

The 3D deformation mechanism of flexspline (FS) is the foundation of harmonic drive. In this paper, a novel methodology based on Rayleigh-Ritz method (RRM) is proposed to solve the three-dimensional elastic deformation of FS. First, the analytical model of RRM for 3D elastic deformation is formulated. A three-dimensional displacement trial function is designed according to the structure and constraints of FS. The RRM improves the accuracy of the solution by increasing the number of terms of the trial function. According to the completeness of the trial function, the real elastic deformation state can be approached arbitrarily in theory. The convergence efficiency of the actual iteration process is greatly affected by the iteration strategy. Therefore , an accelerated convergence strategy is proposed to overcome the drawback of poor convergence rate in the general iterative process. The elastic deformation characteristics of FS are studied by the new method, and a sensitivity analysis of structural parameters is performed. The results demonstrate that the new method is highly accurate and efficient. The radial deflection is slightly arch-shaped along the axial direction, reaching the maximum value near the axial position of the displacement constraint. The tangential deflection is 0 on the symmetry plane, and the value is smaller when it is farther away from the symmetry plane, which reflects the tendency of the gear tooth deflecting towards the major shaft section of the wave generator. The descending order of sensitivity of structural parameters affecting taper deformation is cylinder length (Pl), radii difference (Pd), cylinder thickness (Pt), hole radius (Ph), fillet radius (Pf) and gear rim width (Pw). The descending order of sensitivity of structural parameters affecting tooth skewness is Pl, Pd, Ph, Pf, Pw and Pt. [ABSTRACT FROM AUTHOR]

Although only a few of the ancient masonry arch bridges (MABs) are in fairly good condition today, many ancient arch bridges are still in use. Over time, the condition of the masonry bridges declines and the safety requirements change. Therefore, it is important to examine these bridges under different influences. The strengthening of MABs is generally not essential. The major cause of damage to MABs is their insufficient width and height, and thus, it is not the safety but the usability that has restricted the life-time of the MABs. Therefore, in this investigation, the effect of the arch height on the static and dynamic behavior of a single-span MAB was investigated. For this aim, the Ancient Tokatlı Bridge, built in Karabük, Türkiye, was selected for investigation under near-fault (NF) and far-fault (FF) ground motions (GMs). To observe the altitude of the arch warp on the ancient MAB, first, the finite element model (FEM) was utilized, using ANSYS and SAP 2000. Furthermore, to constitute the arch warp's influence on a MAB, the FEM was remodeled considering the different arch warps between 7.0 and 9.0 m. Moreover, GMs were applied to the FEM to investigate the effect of dynamic behavior. Under these GMs, stresses and strains (compression and tensile) were observed and compared with each other. Consequently, at the end of these investigations, it was observed that the maximum motions were reduced, while the height of the one-span MAB was increased under NF and FF GMs, and this was also true for the contrary situations. The compression stresses were not observed to be hazardous at the point of destruction, while the altitude of the one-span MAB increased. [ABSTRACT FROM AUTHOR]

A reasonable and efficient loading scheme is needed to guarantee the success of large-scale bridge tests. In this study, an array-type, self-balancing pulley-group loading system was designed based on the world's largest spanning arch bridge using a 1:10 scale model test. Automatic statistics of the required load at each loading point were realized using ANSYS, and a load optimization algorithm for loading points at different construction stages was proposed. Tests were carried out separately for the loading system using a single set of pulley groups and an array-type pulley group. Finite element models of the model bridge and the original bridge were established separately using ANSYS, and the stress results of different components during different construction stages of the main arch ring were compared. The research results show the following: (1) The load magnification factor of the single-pulley-group loading device is approximately 6.6 times, with a mechanical efficiency of 94.26%. (2) In the array-type loading system, the actual load at each loading point can reach the design value. The self-balancing characteristic of this system can eliminate the impact of vertical deformation of the structure on loading accuracy, verifying the reliability of the system. (3) The simulation results of the original bridge and the model bridge coincide well, and the stress of each component during the construction process has the same trend. At key construction stages, the maximum relative errors of the stress results of the rigid steel frame and the concrete inside the pipe of the two bridges are 8.33% and 9.34%, respectively, and the maximum absolute error of the bottom plate concrete is 0.66 MPa, verifying the correctness of the counterweight-optimization method. The loading scheme proposed in this paper can provide a reference for the design of loading systems with the same type of scale model test. [ABSTRACT FROM AUTHOR]

Summary: H‐shaped circular arc is a relatively novel type of open‐web steel arch, and currently, no reports have been published concerning its in‐plane stability. In this paper, the elastic and elastic–plastic in‐plane stability of the H‐shaped hollow circular arch is studied by theoretical deduction combined with numerical simulation. First, the overall shear rigidity of the H‐shaped circular arch is calculated, and the elastic buckling load formula of the arch is proposed and verified considering double shear deformation under full‐span radial and uniform loading. The overall elastic buckling load deduced in this paper is reasonable according to the finite element analysis. The results indicate that the influence of shear deformation on the overall elastic buckling load of the arch decreases with the increase of the span length. The arch‐bearing capacity is the largest when the rise‐span ratio is 0.25. Second, the restriction conditions necessary for avoiding local buckling of the chordal web before integral buckling of the H‐shaped steel hollow circular arch are analyzed. Finally, the elastic–plastic failure mechanism of the H‐shaped arch under full‐span radial and uniform loading is examined, and the formula for determining the ultimate bearing capacity that is achievable before failure under full‐span radial and uniform loading is proposed. ANSYS analysis shows that under the radial uniform loading, the chordal bars will yield near 1/4L and 3/4L, and ultimately, the structural failure of the lower chord occurs in the vicinity of 1/4L. The formulas presented in this paper agree well with the results obtained from the finite element analysis and can be used as a reference for engineering applications. [ABSTRACT FROM AUTHOR]

Copyright of Railway Construction Technology is the property of Railway Construction Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Railway Standard Design is the property of Railway Standard Design Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To investigate the reasonable range of the inclination angle of arch ribs, a spatial finite element method was employed based on a concrete-filled steel tube (CFST) basket-handle through an arch bridge with a span of 360 m. A spatial finite element model was established using Midas/Civil software, which was verified with actual bridge data. The effects of different arch rib inclination angles were investigated under static loads. The structural natural frequencies, linear elastic stability coefficients, internal forces, and displacements were comprehensively considered to determine the reasonable range of the inclination angle. The results show that when the inclination angle ranges between 8° and 10°, the first, third, and sixth natural frequencies of the structure are increased. It effectively improves the lateral and torsional stiffness of the arch ribs while ensuring optimal out-of-plane stability of the arch ribs. Compared with the parallel arch, the stability is improved by 20.2%. The effects of angle variation on displacement and internal force of the arch ribs were not significant. Considering all indicators, the optimal range of the inclination angle for the arch ribs of 300-m-level highway CFST arch bridges is suggested to be 8~10°. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Northeast Petroleum University is the property of Journal of Northeast Petroleum University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

High long-term stress on the plantar fascia (PF) is the main cause of plantar fasciitis. Changes in the midsole hardness (MH) of running shoes are an important factor leading to the alteration of the PF. This study aims to establish a finite-element (FE) model of the foot–shoe, and investigates the effects of midsole hardness on PF stress and strain. The FE foot–shoe model was built in ANSYS using computed-tomography imaging data. Static structural analysis was used to simulate the moment of running push and stretch. Plantar stress and strain under different MH levels were quantitatively analyzed. A complete and valid 3D FE model was established. With an increase in MH from 10 to 50 Shore A, the overall stress and strain of the PF were decreased by approximately 1.62%, and the metatarsophalangeal (MTP) joint flexion angle was decreased by approximately 26.2%. The height of the arch descent decreased by approximately 24.7%, but the peak pressure of the outsole increased by approximately 26.6%. The established model in this study was effective. For running shoes, increasing the MH reduces the stress and strain of PF, but also imposes a higher load on the foot. [ABSTRACT FROM AUTHOR]