The 12th International Conference on Fracture Fatigue and Wear (FFW 2024)

Abstract: Next generation rolls such as super-cermet rolls and all-ceramic rolls can be manufactured using only sleeve assembly type rolls and have the advantage of being able to reuse the shaft by replacing the damaged sleeves. However, in some cases failures with unknown causes may occur such as circumferential slippage, shaft pull-out or residual bending deformation at the shrink-fit interface. Such slipping failures cannot be prevented by conventional design concept. This is because even if the resistant torque is greater than the motor torque, the circumferential slippage will occur, and the shaft will come off even if there is no external force. In order to prevent slip failures, we realize the phenomena through numerical simulations, and we clarify the localized slip accumulation that causes sleeve slip during roll rotation. We also identify the geometry of slipping defect through miniature roll experiments. Based on those results, we estimate the fatigue strength of sleeve assembly rolling rolls considering slip defects. The results show that by preventing the slip damage, the fatigue strength of sleeve rolls is almost equivalent to that of conventional solid rolls without shrink-fit.

Biography: Nao-Aki Noda, born in 1956, BA in Mechanical Engineering in 1979, and ME in Mechanical Engineering in 1981, both from Kyushu Institute of Technology, Japan. He received a Ph.D. in Mechanical Engineering in 1984 from Kyushu University, Japan. He worked at Kyushu Institute of Technology from 1984 as an Assistant Professor, Associate Professor and Professor. From 2022, he is a Professor Emeritus. 1) He analyzed the stress concentration factors (SCFs) for notched test specimens by using the body force method. Then, he proposed the SCF formulas within 1% error in their papers. The formulas provide SCFs under arbitrary dimension of the notch including blunt and sharp notches and shallow and deep notches in the specimens. Also, he rigorously solved several singular integral equations and obtained the exact variation of the stress intensity factors of a semi-elliptical surface crack. For those achievements related to stress analysis, he received JSMS Academic Contribution Award from Japan Society of Materials Science. 2) In joint research with Hitachi Metal, they first started developing all ceramic rolls for use in continuous galvanizing lines (CGLs). He contributed by clarifying methods for reducing tensile stress during immersion in molten metal and during operation. Regarding the ceramic rolls, the group received Sokeizai Industry Technology award from Materials Process Technology Center Japan. Shrink-fitting was found to be essential for the joint of such ceramic rolls, but on the other hand, the shaft slipped out during operation. He realized this new phenomenon in the numerical experiments and clarified that irreversible local slip accumulation causes the failure. Regarding this achievement, Nao-Aki Noda received and JSDE Best Paper Award from Japan Society for Design Engineering. 3) Regarding rolling rolls, he investigated the relation between heat treatment and residual stress through joint research with two roll manufacturing companies. In line with the actual situation, creep deformation was also incorporated into the analysis. Using the obtained residual stress as the initial condition, they also analyzed the stress during rolling clarifying the critical regions at the HSS/DCI boundary of the bimetallic roll and evaluated the fatigue strength of the roll. Regarding those collaborations, Nao-Aki Noda received JSMS Branch Distinguished Service Award. 4) There is an idea to shift the structure of rolling rolls to a sleeve assembly type, which can be a candidate to satisfy the requirements beyond the limits of current rolls as well as to reduce costs. However, even if the sleeve roll is designed so that it does not slip during rolling, the sleeve sometimes slips in the circumferential direction. This sleeve slip cannot have been explained by the conventional design criteria (driving torque < frictional resistance torque). Therefore, his group verified this by numerical experiments using load shifting method, and simulated experiments using miniature rolls. They clarified the process of damage on the inner surface of the sleeve. Regarding those collaborations, Nao-Aki Noda received JSME Materials & Mechanics Division Award, Contribution Award. 5) Nao-Aki Noda also studied several fastening elements. Nao-Aki Noda also showed that the adhesive strength can be expressed as a constant value of ISSF (Intensity of Singular Stress Field). He proposed a desirable specimen geometry of lap joint, which is not affected by bending deformation. He clarified the ISSF under pull out test and microbond test used to estimate fiber bonded strength in fiber reinforced composites. Regarding the achievement, he received JCOM Award for Scientific Papers from JSMS. Regarding a series of pioneering research on strength design in adhesive, joining and fastening, he received JSME Materials & Mechanics Division Award, Achievement Award.

Abstract: The hoisting ropes of large equipment (such as coal mine shaft, deep-sea drilling rig) are subjected to alternating tension fatigue load and bending fatigue load. They result in fatigue load of the steel wire inside the rope, contact load and relative slip between adjacent steel wires. Then fretting wear, crack initiation, crack propagation and final fracture of steel wire will occur, that is, fretting fatigue. Serious fretting fatigue inside the rope can reduce the load strength and service life of hoisting rope. However, at present, there is no quantitative evaluation method for the service life of hoisting rope based on fretting fatigue damage. It is impossible to predict the actual service life and service reliability of hoisting ropes, which seriously affects the safety and reliability of large equipment. In order to evaluate the hoisting rope life, we carried out the wire fretting fatigue experiment. Based on the experimental results, combined with the finite element method, tribology theory, fatigue and fracture mechanics theory, we constructed the fretting fatigue wear evolution model, crack initiation prediction model and crack propagation prediction model of steel wire. The fretting fatigue life prediction model of steel wire considering wear, crack initiation and propagation was proposed. Based on the bending fatigue experiments of wire rope and finite element analyses, we proposed the hoisting rope life prediction model based on fretting fatigue. The results show that the service life prediction result of hoisting rope is accurate.

Biography: Da-Gang Wang, born in 1984, BA in Mechanical Engineering in 2007, and Ph.D. in Mechanical Engineering in 2012, both from China University of Mining and Technology, China. From 2010-2012, he studied as a joint doctoral student at the University of Wuppertal in Germany. He worked at School of Mechanical and Electrical Engineering, China University of Mining and Technology from 2013. His current position is a Professor and Director of Mechanical Design department. His research areas cover the fretting tribology and Intelligent Damage Identification. 1) With the background of hoisting wire rope in mine, he carried out research on multi-axial fretting fatigue damage of steel wire under complex working conditions and environment, explained the fretting damage mechanism of steel wire, and proposed the fretting fatigue life prediction model and the life prediction model of steel wire rope. 2) He conducted an evaluation study on the service safety of the main cable of a long-span suspension bridge. He carried out theoretical and simulation analysis on the mechanical characteristics of the main cable of the suspension bridge, and explored the tribo-corrosion, tribo-corrosion-fatigue, dynamic contact and micro-slip behavior of the main cable wires through experiments. Based on the experimental and simulation results, he proposed an anti-skid safety evaluation of the main cable strands. 3) Da-Gang Wang also studied the deterioration mechanism of hoisting rope of deep sea drilling rig and quantitative identification of damage. The damage mechanisms of bending tribo-fatigue and bending fatigue behaviors of wire rope were revealed through self-made bending tribo-fatigue testing rig and rope fatigue testing rig with multiple pulley sets. Based on magnetic flux leakage detection technology, machine and deep learning technology, the damage of wire rope is quantitatively identified. 4) He presided over more than 8 state-level projects such as the National Natural Science Foundation project, the National key Research and Development Program of China (sub-project), and etc.). 5) He has published 2 academic monographs, more than 100 papers in well-known journals at home and abroad, and authorized more than 50 domestic and foreign invention patents. He is the winner of one hundred outstanding doctoral theses in Jiangsu Province, and has won four provincial and ministerial level scientific and technological progress awards.

Abstract: The aim of this talk is to investigate the large structural dynamic behaviors from structural optimization to condition assessment. In terms of large-scale structures like high-rising Canton tower, Yingwuzhou long-span bridge and high-speed railway system, the introduction of model updating gives an alternative in certain condition assessment. The key idea is to find effective factors like natural frequencies, mode shapes and so on relying on the structural behaviors, which will serve as the basis for iterative updating in further structural optimization and condition assessment. The model updating has been evolved with new algorithms like genetic algorithm (GA), particle swarm optimization(PSO) and so on. These algorithms make the applicability of model updating in large scale structures like long span bridges. In engineering application, the model updating technique can highly improve the design efficiency with optimal solution, as well as to the condition assessment with limited sensors. Some real engineering applications will be introduced to show the applicability of model updating based techniques.

Biography: Yunlai Zhou Jointed the Xi’an Jiaotong University in 2020 as an associate professor of engineering mechanics. Since 2010 Yunlai Zhou has focused his attention mainly on problems related to the nondestructive testing, dynamic and fatigue assessment of engineering structures from both testing and analytical aspects. In particular, by studying and working in Europe (Technical University of Madrid, Lisbon University, Lusofona University, Ghent University), in Singapore (National University of Singapore), and in Hongkong SAR (Hongkong Polytechnic University), he has developed several methods suitable for structural optimization and condition assessment including static, dynamic and fatigue failures. Yunlai Zhou has conducted both theoretical and experimental studies in nondestructive testing techniques like phased array ultrasonic testing (PAUT), electromagnetic acoustic transducer (EMAT). He has an outstanding expertise in nondestructive testing system design, data analysis for structural optimization and condition assessment.
The work done in the above research areas has led to more than 100 scientific papers 2012-2022 (of which more than 60 articles in international peer-reviewed scientific journals) as well as to 3 books devoted to the structural dynamic analysis from structural optimization to health monitoring (Magd Abdel Wahab, Yunlai Zhou, Nuno MM Maia (2018). Structural Health Monitoring from Sensing to Processing. IntechOpen Press. ISBN: 978-1-78923-788-7, Print ISBN: 978-1-78923-787-0. Yunlai Zhou, Magd Abdel Wahab (2019). Bridge optimization, inspection and condition monitoring. IntechOpen Press. ISBN: 978-953-51-8054-8. Yunlai Zhou, Magd Abdel Wahab, Nuno MM Maia, Linya Liu, Eloi Figueiredo (2019). Data Mining in Structural Dynamic Analysis. Springer Nature Singapore Pte Ltd. 2019. ISBN: 978-981-15-0500-3).

His scientific outputs have received much attention from the international scientific community, with obtaining more than 1100 citations and an h-index of 19 with more than 5.65k from Google Scholar. He is associate editor of two international journals, KSCE Journal of civil engineering, and Frontiers in Smart Materials, also he is a member of the Editorial Boards of more than 6 international journals including Shock and Vibration, Advances in Mechanical Engineering(SAGE) and so on.