Review
Materials Science, Multidisciplinary
Kun Zhang, Jian-Ping Tan, Wei Sun, Kamran Nikbin, Shan -Tung Tu
Summary: This article discusses the failure behavior and life prediction of engineering materials under multiaxial loading. A multiaxial stress rupture criterion (MSRC) is proposed to distinguish different failure modes, and a multiaxial factor alpha is developed to quantify the multiaxial response of material/geometry combinations. Different methods for determining MSRC are evaluated, and the use of continuum damage mechanics approaches in determining MSRC is recommended, considering the influence of creep failure mechanisms. The correlation between uniaxial material parameters and alpha is also analyzed. The study finds that the increase of uniaxial creep ductility parameter lambda is accompanied by a decrease in alpha, indicating the role of creep ductility in the multiaxial rupture behavior of materials.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2023)
Article
Engineering, Multidisciplinary
T. R. C. Chuaqui, A. T. Rhead, R. Butler, C. Scarth
Summary: A novel Bayesian optimisation framework is proposed for designing stronger stacking sequences in composite laminates, incorporating high-fidelity progressive damage finite element modelling and data-driven optimisation methodology. The framework efficiently establishes aerospace design guidelines by considering typical design constraints and ensuring good feasible solutions are found.
COMPOSITES PART B-ENGINEERING
(2021)
Article
Engineering, Multidisciplinary
Sai-Sai Guo, Jian-Guo Gong, Peng Zhao, Tian -Ye Niu, Fu-Zhen Xuan
Summary: This study investigates the time-dependent microstructural evolution and its dependence on stress state in 9-12% Cr steel notched components through creep tests with different root radii. The results show that during the transient stage, there is a significant redistribution of stress state, which affects the nucleation or growth of cavity. Precipitate coarsening is heterogeneous and promoted by high equivalent stress or stress triaxiality. In the steady stage, the magnitude of stress state influences the creep damage behavior, with higher cavity density and greater reduction in hardness observed in regions with high equivalent stress and stress triaxiality.
INTERNATIONAL JOURNAL OF PRESSURE VESSELS AND PIPING
(2023)
Article
Materials Science, Multidisciplinary
D. Breslavsky, A. Senko, O. Tatarinova
Summary: Experimental study on creep-damage processes in notched specimens subjected to static and periodic loading was conducted, followed by simulations using Rabotnov evolution equation. Constitutive equations for dynamic creep were derived using asymptotic and averaging methods. Numerical results were obtained through FEM and predictor-corrector time integration scheme, while fracture process was studied through a designed numerical procedure. Qualitative differences in crack propagation processes between static and periodic loading conditions were observed.
INTERNATIONAL JOURNAL OF DAMAGE MECHANICS
(2021)
Article
Mechanics
Jianhui Liu, Yingbao He, Kongyong Wu, Xiangbin Yi, Jie Wang, Xuemei Pan
Summary: A new probabilistic fatigue model combining the weakest link theory with critical plane theory is proposed in this study. The critical plane location is determined and a critical damage region considering the size effect is defined to establish the effective stress. The model is validated and compared using experimental data, showing higher accuracy compared to other models.
EUROPEAN JOURNAL OF MECHANICS A-SOLIDS
(2023)
Article
Engineering, Mechanical
Dongxu Zhang, Menghui Lv, Zhixun Wen
Summary: A unified creep rupture life prediction method based on continuum damage mechanics under multiaxial stress was proposed in this paper. By optimizing the traditional skeletal point stress method, the number of models that need to be computed during the simulation was reduced by 5/6, and the generality of the method for different notch sizes was significantly improved. Creep tests on Ni-based superalloy round bar specimens with different notch sizes were conducted to verify the accuracy of the method. Furthermore, creep rupture mechanism analyses were conducted for different notch sizes by combining finite element simulations with experiments, stress and damage were analyzed, and void growth was explained based on triaxial stress states.
ENGINEERING FAILURE ANALYSIS
(2023)
Article
Nanoscience & Nanotechnology
Tian-Ye Niu, Peng Zhao, Gang Zhu, Jian-Guo Gong, Fu-Zhen Xuan
Summary: This study elucidates the effects of different stress states on creep damage mechanisms in 9-12%Cr steels under long-term high temperature exposure. Equivalent stress and stress tri-axiality have different impacts on the creep damage behavior of notched components, with the variation of stress states being evidenced by hardness distribution.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Materials Science, Multidisciplinary
Jian Zhu, DaSheng Wang, ShiYi Bao, Qiang Zhou, ZaiXiang Qin, FengPing Zhong, JianFeng Mao
Summary: In-vessel retention (IVR) is a key strategy to ensure the structural integrity of RPV under severe accidents, where multiaxial creep is the main failure mode. The phase transition and grain boundary precipitation of 16MND5 steel have significant impacts on creep behaviors. Additionally, a new model incorporating the term of activation energy Q based on the Kachanov-Robotnov continuous damage model (CDM) has been developed to study the damage evolution and multiaxial creep behaviors of 16MND5 steel, showing good agreement with experimental results.
JOURNAL OF NUCLEAR MATERIALS
(2022)
Article
Chemistry, Physical
Maxim Lutovinov, Radim Halama, Jan Papuga, Michal Bartosak, Jiri Kuzelka, Milan Ruzicka
Summary: This paper presents an approximate method for calculating elastic-plastic stresses and strains on the surface of notched samples. The method is based on the Abdel-Karim-Ohno cyclic plasticity model and considers the plane stress condition. The comparison between the computational solution and experimental results demonstrates the effectiveness of the proposed method for multiaxial axial-torsion load cases.
Article
Engineering, Mechanical
Nayden Matev, Robert A. Ainsworth, Meini Su, Mark Stevens, Alan Jappy
Summary: The article discusses the numerical simulation of creep relaxation of a cruciform plate subjected to biaxial loading under high temperature conditions, emphasizing the constraints on equivalent stress drop. By varying the biaxial stress ratio, plate geometry, and creep model parameters, the study investigates the effects of equivalent stress drop and multiaxial stress changes on creep damage accumulation.
JOURNAL OF PRESSURE VESSEL TECHNOLOGY-TRANSACTIONS OF THE ASME
(2021)
Article
Engineering, Mechanical
Jianhui Liu, Feilong Hua, Shanshan Lang, Yong Ran, Rong Zi
Summary: Based on the von-Mises criterion and Weibull distribution, a fatigue life prediction method suitable for notched specimens is established by considering the influence of stress gradient and non-proportional additional strengthening effects. The proposed method shows higher accuracy in predicting fatigue life compared to other traditional methods, and P-S-N curves under different failure probabilities are provided.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Engineering, Manufacturing
Andrea Rovinelli, Mark C. Messner, David M. Parks, Ting-Leung Sham
Summary: The study investigates the accuracy of effective stress measures in extrapolating from 2D to 3D stress states using simulated data, suggesting that calibrating these measures with triaxial test data would greatly improve accuracy. Some effective stress measures are more accurate than others, especially for highly triaxial stress states.
INTEGRATING MATERIALS AND MANUFACTURING INNOVATION
(2021)
Article
Engineering, Multidisciplinary
Jianhui Liu, Rong Zi, Yaobing Wei, Linjun Xie, Jianren Sun, Bin Li
Summary: A new multiaxial fatigue life prediction method considering stress gradient effects and additional hardening effects is proposed in this paper. By analyzing the equivalent stress distribution and defining a new damage parameter, the fatigue life of notched specimens can be estimated more accurately. The research results show that the proposed method achieves higher accuracy compared to the equivalent stress method under proportional and non-proportional loading.
INTERNATIONAL JOURNAL OF PRESSURE VESSELS AND PIPING
(2022)
Article
Engineering, Mechanical
Feilong Hua, Jianhui Liu, Xuemei Pan, He Zhao, Zhen Zhang, Shanshan Lang
Summary: Based on the nominal stress method and the influence of stress gradient on fatigue life, a fatigue life prediction method combined with the Weibull distribution is proposed. The accuracy of the model is verified and compared, showing higher accuracy compared to other models. The method can be used to guide actual projects.
INTERNATIONAL JOURNAL OF FATIGUE
(2023)
Article
Chemistry, Physical
Ahmed Bahgat Tawfik, Sameh Youssef Mahfouz, Salah El-Din Fahmy Taher
Summary: This study conducted numerical analysis on notched plain and reinforced concrete beams using different crack simulation techniques and investigated the effects of various parameters on the flexural response. The results showed that XFEM and VCCT produced better results compared to CIT, and that reducing initial notch-to-depth ratio and shear span-to-depth ratio increased flexural capacity. Additionally, the use of external post-tensioning and reinforcement improved the ductility and flexural capacity of the beams.
