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A Mathematical Analysis Method for Bending Problem of Clamped Shallow Spherical Shell on Elastic Foundation

INTERNATIONAL JOURNAL OF COMPUTATIONAL METHODS 2022年第7期19卷

作者： Li, Shanqing Yang, Chunsheng Xia, Fengfei Yuan, Hong Jinan Univ Sch Mech & Construct MOE Key Lab Disaster Forecast & Control Engn Guangzhou Peoples R China

A mathematical analysis method is employed to solve the bending problem of slip clamped shallow spherical shell on elastic foundation. Using the slip clamped boundary conditions, the differential equations of the problem are simplified to a biharmonic equation. Using the R-function, the fundamental solution and the boundary equation of the biharmonic equation, a function is established. This function satisfies the homogeneous boundary condition of the biharmonic equation. The biharmonic equation of the slip clamped shallow spherical shell bending problem on elastic foundation is transformed to Fredholm integral equation of the second kind by using Green's formula. The vector expression of the integral equation kernel is derived. Choosing a suitable form of the normalized boundary equation, the singularity of the integral equation kernel is overcome. To obtain the numerical results, the discretization of the integral equation of the bending problem is conducted. The treatment of singular term in the discretization equation is to use the integration by parts. Numerical results of rectangular, trapezoidal, pentagonal, L-shaped and concave shape shallow spherical shells show high accuracy of the proposed method. The numerical results show fine agreement, with the ANSYS finite element method (FEM) solution, which shows the proposed method is an effective mathematical analysis method.

关键词： Clamped shallow spherical shell elastic foundation bending problem biharmonic equation Green function R-function

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Evolution law of pulsating seepage and thermal deformation by injecting high-temperature steam into coal for thermal coalbed methane recovery

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Deep Underground Science and engineering 2025年第1期4卷 119-131页

作者： Zhiqiang Li Junliang Li Jinsheng Chen Ali Karrech Ningchao Zhang Ju Chang Kaiqi Jin Yangyang Yu Hongbin Wang Aijie Wang MOE Engineering Center of Mine Disaster Prevention and Rescue Henan Polytechnic UniversityJiaozuoChina Collaborative Innovation Center of Coal Work Safety and Clean High Efficiency Utilization Henan Polytechnic UniversityJiaozuoChina School of Safety Science and Engineering Henan Polytechnic UniversityJiaozuoChina Henan Provincial Key Lab of Gas Geology and Control-Cultivation Base of Provincial and Ministry Joint State Key Henan Polytechnic UniversityJiaozuoChina School of Engineering The University of Western AustraliaPerthAustralia

Chinese coal reservoirs are characterized by low pressure and low permeability,which need to be enhanced so as to increase ***,conventional methods for permeability enhancement can only increase the permeability in fractures,but not the ultra-low permeability in coal *** to enhance such impermeable structures lead to rapid attenuation of gas production,especially in the late stage of gas *** stimulation by injecting high-temperature steam is a promising method to increase gas *** critical scientific challenges that still hinder its widespread application are related to the evolution law of permeability of high-temperature steam in coal and the thermal deformation of *** this study,an experimental approach is developed to explore the high-temperature steam seepage coupled with the thermal deformation in coal under triaxial *** tests were conducted using cylindrical coal specimens of?50 mm×100 *** permeability and thermal strain in coal were investigated when high-temperature steam was injected at151.11,183.20,213.65,and 239.76°*** experimental results reveal for the first time that as the amount of injected fluid increases,the steam permeability shows periodic pulsation *** paper introduces and explains the main traits of this discovery that may shed more light on the seepage *** the injected steam temperature increases,the amplitude of pulsating permeability decreases,whereas the frequency increases;meanwhile,the period becomes shorter,the pulsation peak appears earlier,and the stabilization time becomes *** average peak permeability shows a“U-shaped”trend,decreasing first and then increasing as the steam temperature ***,with the extension of steam injection time,the axial,radial,and volumetric strains of coal show a stage-wise expansion characteristic at different temperatures of steam injection,except for the radial strains at 151.11°C.A two-phase flo

关键词： coalbed methane permeability pulsation steam thermal deformation two-phase flow

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Effectiveness and mechanism of microbial dust suppressant on coal dust with different metamorphosis degree

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Environmental Science and Pollution Research 2024年第43期31卷 55437-55446页

作者： Zhao, Yanyun Li, Suning Wu, Mingyue Hu, Xiangming Guo, Yongxiang Wang, Jingqian College of Safety and Environmental Engineering Shandong University of Science and Technology No. 579 Qianwangang Road Xin’an Street Huangdao District Shandong Qingdao China Key Lab of Mine Disaster Prevention and Control Shandong University of Science and Technology No. 579 Qianwangang Road Xin’an Street Huangdao District Shandong Qingdao China

The extraction of coal from open-pit mines significantly contributes to environmental degradation, posing grave risks to human health and the operational stability of machinery. In this milieu, microbial dust suppressants leveraging microbially induced carbonate precipitation (MICP) demonstrate substantial potential for application. This manuscript undertakes an exploration of the dust mitigation efficiency, consolidation attributes, and the fundamental mechanisms of microbial dust suppressants across coal dust samples with varying metamorphic gradations. Empirical observations indicate that, in resistance tests against wind and rain, lignite coal underwent mass losses of 7.43 g·m−2·min−1 and 98.62 g·m−2·min−1, respectively. The production of consolidating agents within the lignite dust, attributable to the microbial suppressants, was measured at 0.15 g per unit mass, a value of 1.25 and 1.07 times greater than that observed in bituminous coal and anthracite, respectively. Scanning electron microscopy coupled with X-ray energy-dispersive spectroscopy (SEM–EDS) and X-ray diffraction (XRD) analyses illuminated that the consolidating products within the coal dust predominantly constituted calcite and vaterite forms of calcium carbonate. The consolidation mechanism of coal dust via microbial suppressants is articulated as follows: Subsequent to the application on coal dust, the suppressants induce the formation of carbonate precipitates with inherent adhesive properties. These carbonates affix to the surfaces of coal dust particles, progressively encapsulating them. Furthermore, they play a pivotal role in bridging and filling the interstices between adjacent dust particles, thereby culminating in the genesis of a dense, cohesive mass capable of withstanding erosive forces. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.

关键词： Coal dust

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Acceleration spectrum analysis of hyperbolic tangent package under random excitation

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PACKAGING TECHNOLOGY AND SCIENCE 2021年第9期34卷 579-587页

作者： Yang, Song-Ping Wang, Zhi-Wei Jinan Univ Packaging Engn Inst Zhuhai 519070 Peoples R China Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou Peoples R China

Many packaging cushion materials follow the hyperbolic tangent type of constitutive relation, so a hyperbolic tangent stiffness non-linearity was derived to describe the stiffness property of the package. Transport package was modelled as the single degree of freedom (SDOF) of hyperbolic tangent spring-mass-damping (SMD) system. The displacement and velocity responses of the system were obtained by Fokker-Planck-Kolmogorov (FPK) equation. Based on the kinematic equation and integral transforming, the approximate analytic solution of the acceleration response power spectral density (PSD) of the hyperbolic tangent package was established for the first time, and the influences of system non-linearities on the acceleration response PSD were investigated. Validation experiment with a complete packaged computer was carried out to verify the proposed approach. Non-linearity of the stiffness influenced the acceleration response PSD through the effect of parameter gamma and statistical moment m(i0). The frequency corresponding to acceleration response peak was determined by the damping correlation coefficient alpha and parameter gamma, which was determined by system characteristic parameter beta, frequency parameter omega(0) and statistical moment m(io). The proposed approach can be used to predict the acceleration response PSD of transport package, and the analysis has important value for packaging optimization design.

关键词： acceleration hyperbolic tangent package PSD random excitation

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Nonlinear vibration of SMA hybrid composite beams actuated by embedded pre-stretched SMA wires with tension-bending coupling effect

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JOURNAL OF SOUND AND VIBRATION 2024年 568卷

作者： Jin, Fusong Zhao, Chen Xu, Peng Xue, Jianghong Lin, Jixin Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China Hubei Engn Univ Sch Mech Engn Xiaogan 432000 Peoples R China

Theoretical and numerical analyses for nonlinear vibrations of the shape memory alloy hybrid composite(SMAHC) beam actuated by the pre-stretched shape memory alloy(SMA) fibers with tension-bending coupling effect are presented in this paper. Under the sudden action of thermal temperature, a recovery force and moment are caused in the SMAHC beam due to the phase transition in the SMA fibers, exciting the nonlinear vibration of the SMAHC beam. The onedimensional Brison constitutive model was adopted to express the influence of the phase transition temperature, initial volume fraction of martensite, and pre-strain on the phase transition in the shape memory alloy. On this basis, the constitutive law of the SMAHC beam is built by considering the tension-bending coupling effect and the phase transition in the SMAHC beam. The equation of motion for nonlinear vibration of the SMAHC beam with geometric nonlinearity and material nonlinearity is derived from the Hamilton principle and is discretized into matrix form using the Galerkin method. According to the algorithm of the NewMark-& beta;method, numerical solutions are computed by developing Matlab program and are compared with the results from ABAQUS analysis. It shows that the frequencies and amplitudes of the theoretical calculations are very consistent with those obtained from ABAQUS analysis. In addition, both the theoretical study and ABAQUS simulation indicates that the high frequency for longitudinal vibration is not observed in the spectrum diagram of transverse vibration, while the low frequencies for transverse vibration are captured in the longitudinal vibration. With the established Matlab program, parametric study is carried out to investigate the effect of the temperature and the location of the SMA fibers on the vibration responses of the SMAHC beam. The results from this study indicate that the transverse vibration of SMAHC beams is characterized as one of low frequency, while the longitudinal vibration ha

关键词： SMAHC Von-Karman nonlinear relationships Recovery force Coupling vibration

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Analyzing the Form-Finding of a Large-Span Transversely Stiffened Suspended Cable System: A Method Considering Construction Processes

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World Journal of engineering and Technology 2024年第2期12卷 229-244页

作者： Junyu Chen Yanfei Wang Ke Chen Shiqing Huang Xiaowen Xu MOE Key Lab of Disaster Forecast and Control in Engineering School of Mechanics and Construction Engineering Jinan University Guangzhou China China Construction Second Engineering Bureau Second Company Shenzhen China Department of Civil Engineering Dazhou Technician College Dazhou China Key Laboratory of Product Packaging and Logistics Packaging Engineering Institute College of Packaging Engineering Jinan University Zhuhai China

The precise control of the shape of transversely stiffened suspended cable systems is crucial. However, existing form-finding methods primarily rely on iterative calculations that treat loads as fixed known conditions. These methods are inefficient and fail to accurately control shape results. In this study, we propose a form-finding method that analyzes the load response of models under different sag and stress levels, taking into account the construction process. To analyze the system, a structural finite element model was established in ANSYS, and geometric nonlinear analysis was conducted using the Newton-Raphson method. The form-finding analysis results demonstrate that the proposed method achieves precise control of shape, with a maximum shape error ranging from 0.33% to 0.98%. Furthermore, the relationships between loads and tension forces are influenced by the deformed shape of the structures, exhibiting significant geometric nonlinear characteristics. Meanwhile, the load response analysis reveals that the stress level of the self-equilibrium state in the transversely stiffened suspended cable system is primarily governed by strength criteria, while shape is predominantly controlled by stiffness criteria. Importantly, by simulating the initial tensioning process as an initial condition, this method solves for a counterweight that satisfies the requirements and achieves a self-equilibrium state with the desired shape. The shape of the self-equilibrium state is precisely controlled by simulating the construction process. Overall, this work presents a new method for analyzing the form-finding process of large-span transversely stiffened suspended cable system, considering the construction process which was often overlooked in previous studies.

关键词： Cable Structure Long-Span Structure Form-Finding Analysis Finite Element Simulation Transverse Cable Stiffening System

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Moving Force Identification Based on Group Lasso and Compressed Sensing

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INTERNATIONAL JOURNAL OF STRUCTURAL STABILITY AND DYNAMICS 2022年第15期22卷 2250170-2250170页

作者： Zhang, Luqi Liang, Yi Yu, Ling Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou Peoples R China

Moving force identification (MFI) is one of the challenging tasks in bridge structural health monitoring (SHM). Especially when the vehicles get on and off the bridge, or cross bridge expansion joints and speed humps, the impact of vehicle loads on bridge structures is commonly focused and the accuracy of MFI results still needs further enhancements. To address this issue, a new MFI framework is proposed by using both group sparsity theory and compressed sensing (CS) in this study. Specifically, with the help of the relationship between moving vehicle loads and bridge responses induced by the traffic, a redundant dictionary based on CS is used to establish the motion equation of the vehicle-bridge system in conjunction with classical theory of MFI. A group structure on the sparse coefficient vector of each moving force tends to be divided into different groups (no overlapping), where sparse coefficient vectors and measurement matrices are divided in different groupings and eventually reconstructed for unknown vectors of moving forces. Additionally, the effect of different ratios of number of groups to sparsity (g/k) on the MFI results is considered. Finally, numerical simulations and experimental verifications are carried out to assess the performance and capability of the proposed framework. The illustrated results show that the group lasso could precisely reconstruct the moving forces more accurately after proper grouping. The proposed new MFI framework outperforms the traditional L-2 regularization or CS methods with a higher identification accuracy and a good robustness to measurement noises, which can be effectively used for the MFI problem in practice.

关键词： Moving force identification group lasso compressed sensing block sparse model vehicle-bridge interaction

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Accurately and automatically simulating hysteresis loops of shape memory alloys

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CONTINUUM MECHANICS AND THERMODYNAMICS 2022年第3期34卷 739-761页

作者： Wang, Si-Yu Zhan, Lin Bruhns, Otto T. Xiao, Heng Jinan Univ Coll Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn West Huangpu Ave 601 Guangzhou 510632 Peoples R China Zhejian Univ Coll Aerosp & Aeronaut Engn Hangzhou 310058 Peoples R China Ruhr Univ Bochum Inst Mech D-44780 Bochum Germany

Toward directly simulating pseudo-elastic effects of shape memory alloys, new elastoplastic equations of von Mises type are proposed by correlating the yield surface radius with the yield surface center, thus establishing a new elastoplasticity model characterized by three coupled quantities for isotropic and anisotropic hardening. Within the framework of conventional macroscopic elastoplasticity, it is demonstrated that the new model can exactly reproduce pseudo-elastic hysteresis effects of shape memory alloys, with no need to characterize any microstructural features of solid-solid phase transitions. To this end, explicit expressions for the three hardening quantities introduced are presented in terms of two single-variable functions. Then, exact closed-form solutions are obtained for the uniaxial stress-strain responses in a loading and a subsequent unloading process, and such responses are shown to give rise to a hysteresis loop shaped just by the foregoing two single-variable functions. As such, hysteresis loops of arbitrary shapes can be simulated in a straightforward and accurate manner simply prescribing two single-variable functions shaping such loops. For the first time, cumbersome and time-consuming procedures both for conducting statistical averaging schemes and for identifying numerous unknown parameters may be bypassed with broad applicability.

关键词： Shape memory alloys Pseudo-elasticity Finite strain Elastoplastic equations Combined hardening

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Flow behavior of laval nozzle sets in steam turbine governing stage at low loads

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THERMAL SCIENCE AND engineering PROGRESS 2023年 46卷

作者： Gan, Yiming Huang, Chang Wang, Weiliang Jinan Univ Energy & Elect Res Ctr Zhuhai 519070 Peoples R China Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China

To achieve carbon neutrality, thermal power units (TPU) will be deeply involved in peak regulation, which is crucial for the development of renewable energy generation. However, the efficiency of TPU is significantly reduced at low loads. The main reason for this is that the convergent nozzles in conventional TPU are difficult to efficiently expand steam with large pressure differentials (i.e., pressure ratios below a critical value), and thus the unit is designed to operate in sliding-pressure mode, resulting in a low Rankine cycle efficiency. To reveal the mechanism of energy loss in the governing stage under peak shaving conditions, the flowing behavior of governing stage nozzle sets of a 330 MW steam turbine is investigated by CFD simulation in this study. The results indicated that the shock waves generated by the supercritical streamflow and the angle deviation at the exit of nozzle sets are the main factors leading to energy efficiency degradation. Based on this, two supersonic Laval nozzles were designed and analyzed in the 10 %similar to 40 % load range. Compared with conventional nozzles, the designed supersonic nozzles I and II showed average efficiency improvements of 4.9 % and 5.8 %, respectively, and maximum efficiencies of 6.6 % and 9.5 %, respectively. The research in this paper can provide theoretical support for the design and development of nozzle sets under deep peaking conditions, which can help achieve carbon neutrality.

关键词： Supersonic Laval nozzles Flow behavior Governing stage Carbon neutrality CFD simulation

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Constitutive models of constrained concrete in cross-shaped PEC column under axial compression

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JOURNAL OF CONSTRUCTIONAL STEEL RESEARCH 2024年 215卷

作者： Li, Guofei Li, Yuanping Jinan Univ Sch Mech & Construct Engn Guangzhou 510632 Guangdong Peoples R China Jinan Univ Key Lab Disaster Forecast & Control Engn Minist Educ Peoples Republ China Guangzhou 510632 Guangdong Peoples R China

Based on the influence of lateral constraints, there are two categories of constraint areas within a cross-shaped partially encased composite (CPEC) column: strong constraint areas (SCAs) and weak constraint areas (WCAs). Due to the diverse constraint effects of profile steel on concrete, dissimilar stress-strain constitutive models are exhibited by SCA and WCA, and they contribute differently to the bearing capacity of columns. Based on the constraint mechanism of the CPEC column, the methodologies for partitioning the constraint areas and determining effective constraint coefficients and strength enhancement coefficients of concrete are proposed to establish the constitutive model of constrained concrete. A formula that accounts for the constraint effect is proposed for estimating the axial compressive ultimate capacity of CPEC columns based on the limit equilibrium method. The study demonstrates that the strength of concrete in SCA is significantly enhanced compared with unconstrained concrete, resulting in an increased bearing capacity. The calculated axial load-displacement curves of columns using the derived constrained concrete constitutive models in this study are in good agreement with experimental results. The derived axial compressive ultimate bearing capacity formula quantifies the constraint effect of concrete with high computational accuracy.

关键词： CPEC column Constrained concrete Stress-strain constitutive model Limit equilibrium method Axial compressive ultimate bearing capacity

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