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Effect of specimen configuration and notch root angle on fatigue behavior of novel dissimilar resistance spot welds of AA5754 to HSLA steel

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Procedia Structural Integrity 2022年 37卷 351-358页

作者： Liting Shi Jia Xue Jidong Kang Amberlee S. Haselhuhn Blair E. Carlson School of Materials Science and Engineering Tianjin University 92 Weijin Road Tianjin 300072 China Canmet MATERIALS 183 Longwood Road South Hamilton L8P 0A5 Canada China Automotive Technology and Research Center Co. Ltd. 68 East Xianfeng Road Tianjin 300300 China General Motors Global R&D Center 30470 Harley Earl Blvd Warren MI 48092 U.S.A.

Facing stringent requirements for fuel economy and regulations for greenhouse gas emissions, structural lightweighting using multi-material solutions has become commonplace in the automotive industry. When joining dissimilar materials such as aluminum to steel by resistance spot welding (rSW), a thin layer of brittle intermetallic compound forms at the aluminum-steel interface and dominates mechanical behavior of the joint. In this contribution, rSW of 1.1 mm thick AA5754 sheet to 2.0 mm thick high-strength low-alloy (HSLA) steel sheet was performed using multi-ring domed (Mrd) electrodes and multiple solidification weld schedules to achieve acceptable static joint strength. Load-controlled fatigue tests were conducted and the results show that the fatigue life is longer in the AA5754 to HSLA steel spot welds than that of the 1.1 mm thick AA5754 joined to itself (aluminum-aluminum). Structural stress analysis revealed that all fatigue life data points from both the lap shear and coach peel configurations fall onto a single master curve indicating that the weld nugget diameter is the controlling parameter for fatigue life. Finite element simulation considering material inhomogeneity in the weld further confirms that a large notch root angle at the weld nugget is beneficial to yield longer fatigue life as less maximum principal strain occurs in the aluminum sheet in the AA5754-HSLA steel spot welds.

关键词： Fatigue life resistance spot welding Aluminum-steel dissimilar welding

Predictive model of frailty onset using Bayesian network

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Predictive model of frailty onset using Bayesian network

IEEE International conference on Big data

作者： Yujiro Kawai Eiichi Sakurai Yuki Sugawara Yukihiko Okada Kai Tanabe Akiko Tsukao Shinya Kuno National Institute of Advanced Industrial Science and Technology Tokyo Japan University of Tsukuba Tsukuba Japan Artificial Intelligence Research Center National Institute of Advanced Industrial Science and Technology Tokyo Japan Institute of Systems and Information Engineering Center for Artificial Intelligence Research University of Tsukuba Tsukuba Japan R&D Center for Smart Wellness City Policies University of Tsukuba Tsukuba Japan Tsukuba Wellness Research Co. Ltd Chiba Japan

ISBN: (纸本)9781665480468

In this study, we constructed a model for predicting the future frailty status of individuals based on information regarding their current lifestyle habits. In recent years, as the global population ages, the number of people certified for long-term care has increased. In an effort to prevent the need for long-term care, prediction of the onset of frailty, which is positioned as a preliminary stage of the caregiving state, is gaining attention. However, the onset of frailty takes a long time, and the incidence of frailty differs according to one’s health literacy. Therefore, a prediction is extremely difficult to achieve. In this study, we constructed a prediction model using a probabilistic latent semantic analysis and a Bayesian network. First, the probabilistic latent semantic analysis was conducted to classify individuals according to their health literacy. Second, we constructed a future frailty prediction model using a Bayesian network for each health literacy segment. As a result, we clarified the following: It is more appropriate to predict a future frailty by predicting the future lifestyle using information on the current lifestyle. In addition, more accurate prediction models can be constructed when individuals are divided based on their health literacy.

关键词： Analytical models Semantics Buildings Urban areas Predictive models Big data Probabilistic logic

coupling effect and characterization modeling of iron ore fines mixing and granulating at 0-1 mm

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Journal of Iron and Steel research International 2019年第11期26卷 1154-1161页

作者： dai-fei Liu Xian-ju Shi Chao-jun Tang Hai-peng Cao Jun Li School of Energy and Power Engineering Changsha University of Science and TechnologyChangsha 410114HunanChina Ironmaking Section Wuhan Branch of Baosteel Central Research Institute(R&D Center of Wuhan Iron&Steel Co.Ltd.)Wuhan 430000HubeiChina

Characteristic of iron ore is the essential factor of *** ores,namely specularite,magnetite concentrate and limonite,were selected as adhesion powder to investigate granulating behavior and evolution process of *** and modeling were performed to represent granulating behavior on the basis of selectivity,ballability and adhesion *** mass fraction of water and particles size of adhesion and nucleation were set at(11±1)%,0-1 mm and 3-5 mm,*** results show that selectivity and ballability promote the evolution of *** water absorption rate of specularite and the ballability of limonite are *** coupling effects exist in two ores mixing and present positive effect when the proportion of magnetite concentrate is greater than that of specularite or specularite and limonite *** three ores mixing,the coupling effect presents a complex superposition state.A characterization model of adhesion rate of mixing granulation was established by random forest *** output is adhesion rate,and its inputs include water absorption rate,balling index and mixing *** model parameters are 957 trees and four branches,and the training and prediction errors of the model are 2.3%and 3.7%,*** indicates that the random forest model can be used to represent coupling effects of mixing granulation.

关键词： Iron ore Granulating coupling effect Modeling random forest algorithm

Magnetic Properties, Anisotropy, and domain Structure of Fe-Based Nanocrystalline Alloy Induced by continuous Stress-Annealing Treatment

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SSrN 2022年

作者： Sun, Haibo Huang, Haohui Wang, Ce Zhang, Jichao Wang, Jinghui School of Materials Science and Hydrogen Energy Foshan University Foshan528000 China Guangdong Key Laboratory for Hydrogen Energy Technologies Foshan University Foshan528000 China Product R&D Center Foshan Zhongyan Magnetoelectric Technology Co. LTD. Foshan528241 China School of Materials Science and Engineering South China University of Technology Guangzhou510640 China Intelligent Manufacturing Institute Foshan Polytechnic Foshan528137 China

The effect of tensile annealing temperature (Ta) on microstructure, soft magnetic properties, magnetic anisotropy, and domain structure for the Finemet nanocrystalline alloy prepared using a home-made continuous tension annealing equipment has been investigated in detail. results show that the Ta has a great influence on the magnetic properties of the nanocrystalline alloy by affecting its stress-induced anisotropy constant (Kμ), average domain width between the strip-like domain patterns (dw) and domain-wall energy (γw). Hereinto, the average anisotropy constant is absolutely dominated by the Kμ under the given Ta range with a constant tension stress of 49.1 MPa. The effective permeability (μe) exhibits a completely opposite variation trend to the physical parameters of Kμ, dw and γw. The corresponding total core loss decreases first and then increases, which is mainly due to the variation of hysteresis loss with the increasing Ta. These results are helpful to obtain the stress-annealed nanocrystalline alloy with excellent soft magnetic properties for the preparation of high-precision and low-loss current transformers. © 2022, The Authors. All rights reserved.

关键词： Annealing

Hydrophobicity and Membrane distillation Performance of Glass Fiber Membranes Modified by dip coating of Pure Pdms

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SSrN 2023年

作者： Pyo, Minsu Jeong, Sanghyun Kim, Jae Hun Jeon, Min Jung Lee, Eui-Jong Department of Environmental Engineering Daegu University 201 Daegudae-ro Jillyang Gyeongsan-si Gyeongbuk38453 Korea Republic of Graduate School of Water Resources Sungkyunkwan University 2066 Seobu-ro Jangan-gu Gyeonggi-do Suwon440746 Korea Republic of Department of Civil and Environmental Engineering Pusan National University Busan46241 Korea Republic of Technology R&D Institute Daelim Industrial Co. Ltd. Joonghak-dong Jongno-gu Seoul110-140 Korea Republic of 125 Yuseong-daero 1689 beon-gil Yuseong-gu Daejeon34045 Korea Republic of

With growing concern for environmental issues associated with the use of has emerged as a promising and eco-friendly alternative. However, few studies have explored the application of pure PdMS solutions through dip coating to achieve hydrophobicity in membranes designed for membrane distillation;a process which demands the membranes possess specific porosity and pore size characteristics. This study explored how dip coating with different PdMS concentrations affected the hydrophobicity and physical properties of glass fiber membranes. Increasing the concentration of up to 15% resulted in a stepwise rise in hydrophobicity, but the functionality as a membrane was compromised when the concentration reached 20%. Hydrophobicity on the membrane surface was higher with 15% PdMS treatment than on the chemically grafted membrane, but the latter demonstrated superior performance in the membrane distillation process. Nevertheless, the study confirms the potential of the pure PdMS-coated membrane as a viable option for membrane distillation, with the possibility of enhancing performance through improvements in pore size and surface morphology. © 2023, The Authors. All rights reserved.

关键词： dip coating

The High Strength Steel with the If and Qp Sandwich Structure to resist the Liquid Metal Embrittlement

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SSrN 2022年

作者： dong, Wufeng Pan, Hua Lei, Ming ding, Kai Gao, Yulai State Key Laboratory of Advanced Special Steel Shanghai University Shanghai200444 China State Key Laboratory of Development and Application Technology of Automotive Steels Shanghai201900 China Automobile Steel Research Institute R&D Center Baoshan Iron & Steel Co. Ltd. Shanghai201900 China Shanghai Engineering Research Center for Metal Parts Green Remanufacture Shanghai200444 China

The development and application of galvanized advanced high strength steels has been significantly hindered by the formation of liquid metal embrittlement (LME), especially in the occasions involved the resistance spot welding (rSW) process. In particular, it is found that there exists a direct correlation between the alloy elements and the formation of the LME cracks. In the present study, a sandwich-structure QP1180+IF steel sheet with the equivalent tensile strength with the QP980 steel is designed and fabricated to resist the LME cracks. The welded joints with normal structure (rSW joint of galvanized QP980 steel) reveal the higher LME susceptibility than the sandwich-structured one. The maximum length of the detected LME cracks is 1,062.9 μm for type I crack (located at the center of the weld) and 152.2 μm for type II crack (located at the shoulder of the weld). Based on the results of the element distribution in the regions near the LME cracks, the internal oxide layer and element segregation are detected for the welded joint with normal structure. The formation of the internal oxide and the element segregation could largely deteriorate the cohesion of the boundaries especially for the region directly contacted with the Zn coating, triggering the formation of the LME cracks. With the protection of the IF steel as the covering layer on the QP1180 steel, however, the regions with element segregation are successfully separated from the Zn coating, dramatically decreasing the corresponding LME susceptibility. In addition, the stress state changed from tensile stress for the welded joint with normal structure to almost compressive stress for the welded joint with sandwich structure, further reducing the tendency to form the LME cracks. © 2022, The Authors. All rights reserved.

关键词： Welds

Fully-coupled Multi-Physical Simulation with Physics-Based Nonlinearity-Elimination Preconditioned Inexact Newton Method for Enhanced Oil recovery

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communications in computational Physics 2019年第1期25卷 244-265页

作者： Huiying Tang Shihao Wang congbin Yin Yuan di Yu-Shu Wu Yonghong Wang State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengduP.R.China Petroleum Engineering Department Colorado School of MinesGoldenCO 80401USA Chuanqing Downhold Service ChengduP.R.China Department of Energy and Resources Engineering Peking UniversityBeijing 100871P.R.China CNPC Engineering Technology R&D Company Limited HoustonTexas 77042USA

In this paper,we introduce a physics-based nonlinear preconditioned Inexact Newton Method(INB)for the multiphysical simulation of fractured *** of solving the partial differential equations(PdE)exactly,Inexact Newton method finds a direction for the iteration and solves the equations inexactly with fewer ***,when the equations are not smooth enough,especially when lo-cal discontinuities exits,and when proper preconditioning operations are not adopted,the Inexact Newton method may be slow or even *** pointed out by Keyes et al.[1],multi-physical numerical simulation faces several challenges,one of which is the local-scale nonlinearity and *** this work,we have proposed and studied a nonlinear preconditioner to improve the performance of Inexact Newton *** nonlinear preconditioner is essentially a physics-based strategy to adaptively identify and eliminate the highly nonlinear *** proposed algorithm has been implemented into our fully coupled,fully implicit THM reservoir simulator(Wang et al.[2,3])to study the effects of cold water injection on fractured petroleum *** results of this work show that after the implementation of this nonlinear preconditioner,the iterative solver has become significantly more robust and efficient.

关键词： Physics-based nonlinearity-elimination Inexact Newton method thermal-hydraulic-mechanical simulation restricted additive Schwarz approach parallel reservoir simulation

Impact of Preprocessing of Graphene Additive Via Ultrasonication on the Electrochemical Performance of Activated Carbon/Graphene composite Lithium-Ion Battery Anodes

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SSrN 2024年

作者： Shahroudi, Hamideh Shaker, Majid Ghazvini, Aliasghar Sadeghi Molababaei, Mahsa Samandari, Hadis Saznaghi, Maryam Hemmati Javanmardi, Shayan Farhadi, Saeed Chameh, Behnam Hajizadeh, Amirhossein riahifar, reza raissi, Babak Yaghmaee, Maziar Sahba Shahalizade, Taieb Department of Nanotechnology and Advanced Materials Materials and Energy Research Center Karaj Iran Lehrstuhl für Physikalische Chemie II Friedrich-Alexander-Universität Erlangen-Nürnberg Egerlandstr. 3 Erlangen91058 Germany Chongqing 2D Materials Institute Liangjiang New Area Chongqing400714 China Department of Materials Science and Engineering Tarbiat Modares University Tehran Iran R&D Center Parthian Battery Novin Co. Ltd Tehran Iran Hafez Ave. P.O. Box 15875-4413 Tehran Iran School of Chemical Engineering College of Engineering University of Tehran Tehran*** Iran Department of Chemistry Iran University of Science and Technology Narmak Tehran*** Iran Department of Technical Physics University of Eastern Finland Kuopio70210 Finland School of Chemistry College of Science University of Tehran P.O. Box 14155- Tehran6455 Iran

In this research, composites of graphene and activated carbon (AC) were used as anode active materials for lithium-ion batteries (LIBs). 5 wt.% graphene was used as additive in powder (GP) and suspension in an organic solvent (GL) forms. The initial discharge capacities and coulombic efficiencies at 0.05 A g-1 were: AC (1578 mAh g-1, 38%), AC-5% GP (2593 mAh g-1, 41%), and AC-5% GL (3969 mAh g-1, 41%). At 5 A g-1, the initial discharge capacities were: AC (81 mAh g-1), AC-5% GP (129 mAh g-1), and AC-5% GL (187 mAh g-1). After 500 cycles, the capacity retention was ~50% for AC, 87% for AC-5% GP, and 100% for AC-5% GL. The AC-5% GL anode exhibited 1528 Wh kg-1 energy density at 19.3 W kg-1 power density and 120 Wh kg-1 at 2386 W kg-1. The superior performance of AC-5% GL was attributed to better dispersion of thinner graphene sheets by efficient exfoliation in the organic solvent, increasing the average pore diameter from 3.00 to 3.87 nm and enhancing electrolyte uptake, as confirmed by nitrogen adsorption-desorption isotherms, contact angle, and wicking tests. The study highlights employing graphene with AC for optimized LIB anode performance. © 2024, The Authors. All rights reserved.

关键词： Lithium-ion batteries

A modified J-C constitutive model and novel strain rate-dependent fracture criterion for A7N01S-T5 under different loading

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International Journal of Impact engineering 2025年 206卷

作者： Haoxu ding Tao Zhu Wenyue Yuan Jinle Wang Xiaorui Wang Bing Yang Shoune Xiao State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong University Chengdu 610031 China R&D Center CRRC Qingdao Sifang Co. Ltd. Qingdao 266000 China School of Mechatronic Engineering Changchun University of Technology Changchun 130012 China

To study the dynamic and static mechanics and fracture characteristics of A7N01S-T5 aluminum alloy in detail, the related research was carried out based on the combination of experiment and simulation. Firstly, the dynamic and static mechanical performance tests under several stress states were carried out, and the stress state parameters and equivalent fracture strain of different tests were obtained based on the finite element reverse engineering method. On this basis, the Von Mises yield function and Lou2022 yield function are used to describe the yield and hardening characteristics of the material under quasi-static conditions, and the dF2016 criterion is used to describe the quasi-static fracture characteristics. Then, the classical and modified J-C constitutive models are used to describe the material's dynamic yield and hardening characteristics. Finally, a new strain rate-dependent fracture criterion is proposed to describe the dynamic fracture characteristics of the material. The results show that the material's mechanical properties are related to the stress state and strain rate. The dynamic and static mechanical properties of A7N01S-T5 aluminum alloy can be well described by the Lou2022 yield function and modified J-C constitutive model. The newly constructed strain rate-dependent fracture criterion can characterize the difference in the influence of strain rate on fracture characteristics under different stress states, and the prediction accuracy is significantly improved compared with the traditional J-C fracture criterion.

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