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Computer Modeling in Engineering & Sciences 2024年第7期140卷 275-304页

作者： Junjie Zhao Diyuan Li Jingtai Jiang Pingkuang Luo School of Resources and Safety Engineering Central South UniversityChangsha410083China

Traditional laboratory tests for measuring rock uniaxial compressive strength(UCS)are tedious and *** is a pressing need for more effective methods to determine rock UCS,especially in deep mining environments under high in-situ ***,this study aims to develop an advanced model for predicting the UCS of rockmaterial in deepmining environments by combining three boosting-basedmachine learning methods with four optimization *** this purpose,the Lead-Zinc mine in Southwest China is considered as the case *** density,P-wave velocity,and point load strength index are used as input variables,and UCS is regarded as the ***,twelve hybrid predictive models are *** mean square error(RMSE),mean absolute error(MAE),coefficient of determination(R2),and the proportion of the mean absolute percentage error less than 20%(A-20)are selected as the evaluation *** results showed that the hybridmodel consisting of the extreme gradient boostingmethod and the artificial bee colony algorithm(XGBoost-ABC)achieved satisfactory results on the training dataset and exhibited the best generalization performance on the testing *** values of R2,A-20,RMSE,and MAE on the training dataset are 0.98,1.0,3.11 MPa,and 2.23MPa,*** highest values of R2 and A-20(0.93 and 0.96),and the smallest RMSE and MAE values of 4.78 MPa and 3.76MPa,are observed on the testing *** proposed hybrid model can be considered a reliable and effective method for predicting rock UCS in deep mines.

关键词： Uniaxial compression strength strength prediction machine learning optimization algorithm

strength prediction of multi-layered copper-based composites fabricated by accumulative roll bonding

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Transactions of Nonferrous Metals Society of China 2021年第6期31卷 1729-1739页

作者： P.SEIFOLLAHZADEH Morteza ALIZADEH M.R.ABBASI Department of Materials Science and Engineering Shiraz University of TechnologyModarres Blvd.71557-13876ShirazIran

This work aims to evaluate the feasibility of the fabrication of nanostructured Cu/Al/Ag multi-layered composites by accumulative roll bonding(ARB),and to analyze the tensile properties and electrical conductivity of the produced composites.A theoretical model using strengthening mechanisms and some structural parameters extracted from X-ray diffraction is also developed to predict the tensile strength of the *** was found that by progression of ARB,the experimental and calculated tensile strengths are enhanced,reach a maximum of about 450 and 510 MPa at the fifth cycle of ARB,respectively and then are *** electrical conductivity decreased slightly by increasing the number of ARB cycles at initial ARB cycles,but the decrease was intensified at the final ARB *** conclusion,the merit of ARB to fabricate this type of multi-layered nanocomposites and the accuracy of the developed model to predict tensile strength were realized.

关键词： multi-layered composites accumulative roll bonding strength prediction hardness X-ray diffraction

prediction of Antifrccze Critical strength of Infant Age Concrete

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Journal of Wuhan University of Technology(Materials Science) 2008年第2期23卷 272-275页

作者： LIU Jun LIU Runqing School of Civil ＆ Hydraulic Engineering Dalian University of Technology Dalian 116024 Liaoning School of Materials Science and Engineering Shenyang Jianzhu University Shenyang 110168 Liaoning

The rule of infant age concrete strength development under low temperature and complex affecting factors is researched. An efficient and reliable mathematical forecast model is set up to predict the infant age concrete antifreeze critical strength under low temperature at construction site. On the basis of the revision of concrete equivalent coefficient under complex influencing factors, least-squares curve-fitting method is applied to approximate the concrete strength under standard curing and the forecast formula of concrete compressive strength could be obtained under natural temperature condition by various effects. When the amounts of double-doped are 10% fly ashes and 4% silica fumes as coment replacement, the antifreeze critical strength changes form 3.5-4.1MPa under different low temperature curing. The equivalent coefficient correction formula of concrete under low temperature affected by various factors could be obtained. The obtained equivalent coefficient is suitable for calculating the strength which is between 10% to 40% of standard strength and the curing temperature from 5-20 ℃. The forecast value of concrete antifreeze critical strength under low temperature could be achieved by combining the concrete antifreeze critical strength value with the compressive strength forecast of infant age concrete under low temperature. Then the theory for construction quality control under low temperature is provided.

关键词： low temperature concrete infant age equivalent coefficient least-squares curve-fitting strength prediction

prediction of end-roll strength and rapid adjustment of the on-the-spot composition in automobile cross beam steel

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Progress in Natural Science:Materials International 2004年第12期 72-76页

作者： LIU Zhilin, LIU Weidong and LIN Cheng*(Department of Materials and Chemical Engineering, Liaoning Institute of Technology, Jinzhou 121001, China)

According to the hot working technology, the calculating formulas of the end roll strength in the automobile cross beam steel have been given in theory with electron structure parameters of the alloying phase and the biphase interface. The relationships among the chemical composition, the end roll grain size and the strength, achieved by calculations, are applied to predetermine the optimal end roll grain size and chemical composition range to satisfy the technical requirements. In the productive process, according to the on the spot result analyzed, the computer can calculate the value of end roll strength quickly, and the on the spot composition can also be adjusted in accordance with the demand until the composition is up to the technical requirements. The forecast is fit for all the non quenched tempered steels.

关键词： electron structures of alloy phase and biphase interface strength prediction composition adjustment.

Global nonequilibrium energy criterion for predicting strength of 316L stainless steel under complex loadings:Theoretical modeling and experimental validation

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Science China(Physics,Mechanics & Astronomy) 2022年第4期65卷 62-71页

作者： Yanying Hu Jiapeng Chen Biao Wang Sino-French Institute of Nuclear Engineering and Technology Sun Yat-Sen UniversityZhuhai 519082China School of Physics Sun Yat-Sen UniversityGuangzhou 510275China

Classical strength criteria are developed based on some empirical assumptions and have been widely used in engineering to predict material strength owing to their simplicity. In some cases, however, considerable discrepancies arise between classicalstrength-criteria-based theoretical predictions and experimental results. Recently, a global nonequilibrium thermodynamics model has made important progress over classical models without resorting to any empirical assumptions. A prominent advance of this rational energy model is that it straightforwardly determines the dissipation energy density function, which is pertinent to inherent material ductility, through simple uniaxial and equi-biaxial tensions. In this study, a brief introduction of the nonequilibrium energy model was followed by systematic experimental investigation to determine the dissipation energy function and predict the material strength of pristine 316 L stainless steel-commonly used in engineering-under complex loadings. The results indicated that the strength contours predicted by the nonequilibrium energy criterion for complex loadings are consistent with the experimental results obtained for biaxial tension, implying that the nonequilibrium thermodynamics model is both reasonable and reliable. The prediction error was presumed to be induced by the anisotropy of the 316 L stainless steel sheets.

关键词： failure criterion nonequilibrium process 316L stainless steel strength prediction complex loading

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Damage Failure Analysis of Z-Pins Reinforced Composite Adhesively Bonded Single-Lap Joint

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Computer Modeling in Engineering & Sciences 2021年第3期126卷 1239-1249页

作者： Yinhuan Yang Manfeng Gong Xiaoqun Xia Yuling Tang School of Electromechanical Engineering Lingnan Normal UniversityZhanjiang524048China Tianjin Key Laboratory of Integrated Design and On-line Monitoring for Light Industry&Food Machinery and Equipment Tianjin University of Science&TechnologyTianjin300222China

In order to study themechanical properties of Z-pins reinforced laminated composite single-lap adhesively bonded joint under un-directional static tensile load,damage failure analysis of the joint was carried out bymeans of test and numerical *** failure mode and mechanism of the joint were analyzed by tensile failure *** to the experimental results,the joint exhibits mixed failure,and the ultimate failure is Z-pins pulling out of the *** order to study the failure mechanism of the joint,the finite element method is used to predict the failure *** numerical results are in good agreement with the experimental results,and the error is 6.0%,which proves the validity of the numerical *** progressive damage failure analysis,it is found that matrix tensile failure of laminate at the edge of Z-pins occurs first,then adhesive layer failure-proceeds at the edge of Z-pins,and finally matrix-fiber shear failure of the laminate takes *** the increase of load,the matrix-fiber shear failure expands gradually in the X direction,and at the same time,the matrix tensile failure at the hole edge gradually extends in different directions,which is consistent with the experimental results.

关键词： Z-pins reinforced composite adhesively bonded single-lap joints failure mode uniaxial tensile test strength prediction progressive damage

DAMAGE MECHANISM ANALYSIS OF 2D 1×1 BRAIDED COMPOSITES UNDER UNIDIRECTIONAL TENSION

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Transactions of Nanjing University of Aeronautics and Astronautics 2013年第4期30卷 317-327页

作者：张超许希武陈康 State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and Astronautics

Coupling with the periodical displacement boundary condition,a representative volume element(RVE) model is established to simulate the progressive damage behavior of 2D1×1 braided composites under unidirectional tension by using the nonlinear finite element ***-Wu failure criterion with various damage modes and Mises criterion are considered for predicting damage initiation and progression of yarns and *** anisotropic damage model for yarns and the isotropic damage model for matrix are used to simulate the microscopic damage propagation of 2D1×1braided ***′s damage tensor is adopted to characterize each damage *** the simulation process,the damage mechanisms are revealed and the tensile strength of 2D1×1braided composites is predicted from the calculated average stress-average strain *** results show good agreement with experimental data,thus the proposed simulation method is verified for damage mechanism analysis of 2D braided composites.

关键词： 2D braided composites representative volume element (RVE) failure modes damage mechanism strength prediction