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Reinforcing shell elements for fiber-reinforced composites undergoing large deformations and general motion

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Composite structures 2025年 366卷

作者： Li, Yanhu Lu, Yongjie Song, Jibo Zhang, Linao State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University No. 17 North 2nd Ring East Road Shijiazhuang Hebei050043 China School of Mechanical Engineering Shijiazhuang Tiedao University No. 17 North 2nd Ring East Road Shijiazhuang Hebei050043 China Department of Mechanical and Electrical Engineering Shijiazhuang College of Applied Technology No. 226 Tianning Road Shijiazhuang Hebei050043 China

Fiber-reinforced composites offer excellent mechanical properties and lightweight advantages in multibody systems. However, their significant anisotropy and geometrical and material nonlinearities present challenges for accurate modeling and simulation. In this paper, two new types of reinforcing shell elements are developed within the Absolute Nodal Coordinate Formulation framework. The first type assumes that each fiber behaves as an Euler beam with only tensile and bending stiffness, making it suitable for simulating reinforcing fibers with arbitrary orientations and nonuniform materials and cross-section areas. The second type employs elastic force formulation based on Kirchhoff–Love theory or continuum mechanics. It is suitable for simulating reinforcing fibers that appear in a layered form with unique orientation, material, and cross-section area. The fibers and matrix are described independently in these new reinforcing elements, coupled through consistent deformation compatibility conditions. This approach allows different material models and element formulations for the fibers and matrix to be used. Furthermore, multiple fibers (or layers) can be embedded within a single reinforcing shell element, providing more accurate representations of the actual physical structure. The effectiveness of the developed reinforcing elements is validated through several benchmark problems. Numerical results demonstrate that both types of reinforcing shell elements are locking-free and can automatically capture the reinforcing effects of the fibers and the coupled deformation modes. This investigation enriches the element library of the Absolute Nodal Coordinate Formulation and provides an effective tool for the accurate simulation and optimal design of fiber-reinforced composites in multibody systems. © 2025

关键词： Shells (structures)

Indentation Responses of Piezoelectric Semiconductors

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SSRN 2023年

作者： Liu, Jinxi Gao, Shijing Zhang, Zeran Nie, Guoquan Chen, Weiqiu State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China School of Mechanical Engineering Shijiazhuang Tiedao University Shijiazhuang050043 China Department of Engineering Mechanics Hebei Key Laboratory for Mechanics of Intelligent Materials and Structures Shijiazhuang Tiedao University Shijiazhuang050043 China Key Lab of CAD & CG Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province Department of Engineering Mechanics Zhejiang University Hangzhou310027 China

In this paper, the indentation responses of a piezoelectric semiconductor (PSC) half-space by an insulating and rigid spherical indenter are investigated. It is assumed that the contact area between the indenter and the PSC is frictionless. Based on the Hankel integral transformation, the considered indentation problem is reduced to a pair of dual integral equations. Due to the complexity of the coupled governing differential equations, the explicit closed-form expressions for the PSC indentation responses cannot be derived like the piezoelectric counterparts. Therefore, the dual integral equations are converted into the Fredholm integral equation of the second kind, which is numerically solved to determine the concerned responses. These responses include the relationships of the indentation force, the electric potential and the change of carrier concentration with the indentation depth. The numerical results show that the semiconducting property has a significant influence on the indentation characteristics. In addition, the three-dimensional finite element simulations are carried out to validate the theoretical results computed by the singular integral equation method. It turns out that the two results are well consistent. The distributions of the stress and electric potential near the contact area are simulated by finite element method to reveal the effect of the steady carrier concentration. The obtained findings are useful for understanding the interaction between piezoelectricity and semiconducting property. © 2023, The Authors. All rights reserved.

关键词： Indentation

High-speed rail roller bearings with built-in triboelectric sensors

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Cell Reports Physical Science 2025年第5期6卷

作者： Li, Shuai Gao, Shuai Wang, Song Gu, Xiaohui Liu, Yongqiang Zhang, Xiantao Hu, Jian Pennacchi, Paolo Pu, Huayan Luo, Jun Chu, Fulei Han, Qinkai State Key Laboratory of Mechanical Transmission for Advanced Equipment Chongqing University Chongqing 400044 China State Key Laboratory of Tribology Department of Mechanical Engineering Tsinghua University Beijing 100084 China State Key Laboratory of Mechanical Behavior and System Safety of Train Engineering Structures Shijiazhuang Tiedao University Shijiazhuang 050043 China Department of Mechanical Engineering Politecnico Di Milano Via G. La Masa 1 Milan 20156 Italy

To dynamically monitor roller bearings in high-speed trains and computationally predict their fluid dynamics with high precision, this study proposes a built-in, compact, and integrated triboelectric cage speed sensor for double-row tapered roller bearings (TCSS-DTRBs). The design is based on a dual-sided electrode located in the internal space and two polytetrafluoroethylene dielectric layers that rotate synchronously with both cages, forming two freestanding-mode triboelectric nanogenerators that detect motion on both cage sides. Experiments on a full-scale train roller bearing are conducted under two types of lubricating scenarios. The stability and applicability of the monitoring function are validated using two different scale test rigs. Furthermore, setting the skidding results of the TCSS as boundary conditions, a FLUENT model of the DTRB is established to achieve high-precision computational fluid dynamics predictions. The combination of TCSS and fluid dynamics analysis provides a solid foundation for the intelligent design of train roller bearings. © 2025 The Author(s)

关键词： double-row tapered roller bearings fluid dynamics skidding triboelectric nanogenerators triboelectric sensor

Experimental Study on Fluctuating Aerodynamic Force and Wind Pressure Distribution Characteristics of Three Circular Cylinders Arranged Inline

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SSRN 2023年

作者： Liu, Xiaobing Jiang, Huimin Wang, Shibo Liu, Xiqiang Yang, Qun State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China Innovation Center for Wind Engineering and Wind Energy Technology of Hebei Province Shijiazhuang050043 China School of Civil Engineering Shijiazhuang Tiedao University Shijiazhuang050043 China

The fluctuating aerodynamic force and wind pressure distribution characteristics of three circular cylinders arranged inline at different incidence angles and spacing ratios were studied via rigid model pressure measurement wind tunnel tests. The results were compared with those of a single cylinder. The Reynolds number is 6.4×104. The range of incidence angle α and spacing ratio L/D (the ratio of the center distance between adjacent cylinders to the diameter of the cylinder) are 0°~90° and 1.2~4.0, respectively. The spacing ratio and incidence angle greatly influence the fluctuating aerodynamic force coefficients and wind pressure coefficients. According to the spacing ratio, the fluctuating aerodynamic characteristics can be roughly divided into three states: small spacing ratios (1.2≤L/D≤2.0), medium spacing ratios (2.0 © 2023, The Authors. All rights reserved.

关键词： Circular cylinders

Influence of External Structure and Internal Stacking on Wind Load Characteristics of Large Span Spherical Shell Structure

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SSRN 2023年

作者： Liu, Xiaobing Chen, Anjie Yang, Qun Feng, Bin Tian, Xuedong State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China Innovation Center for Wind Engineering and Wind Energy Technology of Hebei Province Shijiazhuang050043 China School of Civil Engineering Shijiazhuang Tiedao University Shijiazhuang050043 China

In order to study the wind load characteristics of the large span spherical shell structure, a rigid model pressure test was conducted in a wind tunnel laboratory to study the effects of different external structures and internal stacking forms on wind loads of a spherical shell structure in an actual project. The variation laws of the shape factor and the integral force coefficient of the spherical shell structure under different test cases are compared and analyzed. The results show that the shape factor of the spherical shell structure is only affected near the interference when the transfer station and trestle are arranged. When the two spherical shell structures are arranged in series and the adjacent spherical shell structure is located upstream, the shape factor of the spherical shell structure is most affected, and there is a significant reduction effect at the bottom of the windward surface. Compared with the external structure, the influence of different internal stacking forms on the shape factor of the spherical shell structure is relatively weak. The interference effect of the adjacent spherical shell structure makes the stress situation of the spherical shell structure better than that of the spherical shell structure without the adjacent spherical shell structure in most wind directions. The integral force coefficient of the spherical shell structure is the highest when the internal stacking is full, and the lowest when there is no internal stacking. Therefore, the integral force coefficient of the spherical shell structure when the internal stacking is full can be used as a reference for the design of the frame of the spherical shell structure. © 2023, The Authors. All rights reserved.

关键词： Shells (structures)

Simplified calculation method for the critical load bearing of market-based profile emergency steel pier

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Heliyon 2024年第22期10卷 e38808页

作者： Liu, Zi-yu Chen, Shi-tong Zhi, Mo-mo Zhang, Kai Zhang, Hong-tao Collaborative Innovation Center for Performance and Security of Large-scale Infrastructure Shijiazhuang Tiedao University Shijiazhuang China Hebei Eng. Innovation Center for Traffic Emergency and Guarantee Shijiazhuang Tiedao University Shijiazhuang China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang China

A novel emergency steel pier, assembled from market-available profiles, has been developed to address the challenges associated with the “regular stockpiling and rapid emergency deployment” of bridge pier repair equipment. These challenges often involve significant labor and financial costs for manufacturing and maintenance. The buckling modes of the columns and pier-girder connections were considered. Using energy methods and plate-shell theory, an analytical formula for the critical load-bearing capacity of the steel pier under emergency conditions was derived. Numerical simulations were conducted for comparison and validation, resulting in an optimized and simplified method for calculating the critical load capacity, which is suitable for engineering applications. The study shows that the critical load-bearing capacity of the emergency steel pier exhibits distinct patterns under the influence of column buckling modes and pier-girder connection methods. In cases where the column is fixed at one end and hinged at the other, or fixed at both ends, the critical load for axisymmetric buckling is affected by factors such as elastic modulus, Poisson's ratio, height, radius, wall thickness, and the number of buckling waves. When considering non-axisymmetric buckling, the number of circumferential buckling waves becomes an additional factor. A simplified method for calculating the critical load-bearing capacity was developed. The simplified formula depends only on a correction factor, modified buckling stress, the number of columns, and cross-sectional area. This makes it highly practical for emergency engineering applications. © 2024

关键词： Critical bearing capacity Emergency Energy method Rush-repair steel pier Standard market profiles Temporary-permanent conversion

Analyzing Convective Heat Transfer in Combined Solar Chimneys: A Theoretical and Numerical Study of key Influencing Parameters

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SSRN 2024年

作者： Cui, Huimin Han, Mengjiao Zhang, Jitao Han, Zhiming Liu, Qingkuan State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China Innovation Center for Wind Engineering and Wind Energy Technology of Hebei Province Shijiazhuang050043 China Department of Mathematics and Physics Shijiazhuang Tiedao University Shijiazhuang050043 China School of Civil Engineering Shijiazhuang Tiedao University Shijiazhuang050043 China

Combined solar chimneys represent a potent mechanism for harnessing solar energy to bolster natural ventilation in green building designs. This study focuses on the impact of structural parameters and external conditions on the ventilation and heat transfer performance of such systems. Through scaling analysis and numerical simulations, we investigate the flow dynamics and heat transfer mechanisms. We examine the influence of five critical control parameters: inclination angle (α), inlet size ratio (h/H), ratio of inclined to vertical section lengths (L/H), Rayleigh number (Ra), and the temperature difference between indoor and outdoor environments (Δθ). Our findings indicate that ventilation intensity escalates with increasing inclination angle, particularly within the range of 15°to 75°, achieving standard requirements at angles of 30° or greater. Ventilation and heat exchange performance exhibit an initial increase followed by a decline as the inlet size ratio expands from 0.10 to 0.40. Optimal ventilation efficiency is observed at a Rayleigh number of 1.98×1014 with an inlet size ratio of 0.15. Conversely, a low ratio of inclined to vertical section lengths (L/H=0.20) correlates with suboptimal ventilation performance. Both ventilation intensity and efficiency are positively correlated with increases in Ra and Δθ. This research quantitatively delineates these relationships, providing a theoretical foundation for the design of natural ventilation systems in sustainable buildings using combined solar chimneys. © 2024, The Authors. All rights reserved.

关键词： Computational fluid dynamics

Analyzing Convective Heat Transfer in Combined Solar Chimneys: A Theoretical and Numerical Study of key Influencing Parameters

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SSRN 2024年

Combined solar chimneys represent a potent mechanism for harnessing solar energy to bolster natural ventilation in green building designs. This study focuses on the impact of structural parameters and external conditions on the ventilation and heat transfer performance of such systems. Through scaling analysis and numerical simulations, we investigate the flow dynamics and heat transfer mechanisms. We examine the mechanism and the influence of three critical control parameters: inlet size ratio (h/H), ratio of inclined to vertical section lengths (L/H), and Rayleigh number (Ra). Our findings indicate that ventilation and heat exchange performance exhibit an initial increase followed by a decline as the inlet size ratio expands from 0.10 to 0.40. Optimal ventilation efficiency is observed at a Rayleigh number of 1.98×1014 with an inlet size ratio of 0.15. Conversely, a low ratio of inclined to vertical section lengths (L/H=0.20) correlates with suboptimal ventilation performance. Both ventilation intensity and efficiency are positively correlated with increases in Ra. This research quantitatively delineates these relationships, providing a theoretical foundation for the design of natural ventilation systems in sustainable buildings using combined solar chimneys. © 2024, The Authors. All rights reserved.

关键词： Computational fluid dynamics

Enhancing Solar Chimney Performance with Novel Passive Optimization Strategies for Dual Carbon Goals

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SSRN 2024年

作者： Han, Mengjiao Cui, Huimin Han, Zhiming Liu, Qingkuan School of Civil Engineering Shijiazhuang Tiedao University Shijiazhuang050043 China Department of Mathematics and Physics Shijiazhuang Tiedao University Shijiazhuang050043 China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang050043 China Innovation Center for Wind Engineering and Wind Energy Technology of Hebei Province Shijiazhuang050043 China

The development of green buildings plays a pivotal role in achieving "dual carbon" goals. This study focuses on the Combined Solar Chimney (CSC) as an effective method for utilizing solar energy to enhance building ventilation and heat exchange, thereby reducing air-conditioning energy consumption. We introduce two innovative passive optimization measures: deflectors and segmented heat-absorbing walls. Using numerical simulations, we analyze the impact of five control parameters—the angle and length of the straight deflector, the central angle of the curved deflector, the number of heat-absorbing wall segments, and the Rayleigh number (Ra)—on CSC performance. Our findings detail the temperature distribution and the vertical vortex dimensions to elucidate underlying mechanisms. Results indicate that air changes per hour (ACH) can be significantly improved with the implementation of deflectors and segmented walls. Optimal deflector configurations are identified as a 25° angle, a 0.375 length-to-width ratio (l/W), and a 60° central angle. The study recommends using two heat-absorbing wall segments for practical applications. When both measures are applied, ventilation performance can be enhanced by up to 25.71%. Additionally, this research establishes quantitative relationships between the control parameters, ACH, and heat exchange efficiencies, providing a theoretical foundation for practical engineering designs. © 2024, The Authors. All rights reserved.

关键词： Solar chimneys