Abstract The phenomenon of bank erosion and collapse is widely distributed in major rivers all over the world, and it is a kind of natural disaster with greater hazards. Bank erosion in seasonally frozen rivers (SFR) is subject to the coupling effects between hydrodynamic forces and freeze-thaw, and the mechanism is complex. Understanding of bank erosion mechanisms is of great significance for river bank protection and comprehensive river management. Taking the downstream near dam section of the Dadingzishan Navigation and Hydropower Project in the mainstream of the Songhua River as an example, the BSTEM model was used to analyze the degrees of riverbank stability in different periods considering the freeze-thaw effect. The results indicated that the degrees of riverbank stability are high during the periods of low water level and water-level rising before the flood season, and the slope toe scour is the main factor; and they are low during the periods of high water level and water-level recession with the continuous bank collapse occurring; The freezing and thawing effect has an important effect on the stability of river banks in the seasonal frozen region. so as to provide a certain reference for the study on the bank collapse of the river in seasonal freezing region and its simulation for the study of riverbank erosion in seasonally frozen rivers.

Bank erosion

Bank

10.1007/978-981-19-6138-0_103

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A Strain Components-Based Mohr–Coulomb Fracture Criterion for Proportional Loadings

Wu Kang Y. Sun Wenchao Xiao Jun Yang

Ductile fracture criteria are essential when using elastoplastic materials such as advanced high strength steels (AHSS) that fail without severe localized necking. It is aimed to figure out the unified mechanism for ductile fracture and accurately describe it with phenomenological criteria. In this paper, the effect of the stress triaxiality and the Lode parameter is analyzed mathematically. The maximum shear strain and the normal strain to fracture are emphasized in the proposed strain components-based Mohr–Coulomb fracture criterion based on the fracture surface observations, and it is assumed that fracture occurs when the linear combination of the maximum shear strain and the normal strain reaches the critical value. It is then extended to describe fracture with the equivalent plastic strain and the normal strain to fracture. The experimental fracture data of AA 2024-T351 and the additively manufactured Ti-6Al-4V titanium alloy are used to verify the proposed models. A fracture forming limit diagram comprising forming limit curves calibrated from stress states under different stress triaxialities is proposed based on the proposed criteria. The study shows that a strong correlation between the maximum shear strain and the normal strain to fracture has been observed, and it can be described piecewise-linearly by the proposed strain components-based Mohr–Coulomb criteria. The proposed fracture forming limit diagram includes both the effect of the stress triaxiality and the Lode parameter and can assess the risk of failure properly. The results provide a new insight into the intrinsic deformation and fracture mechanism of materials that fail without severe localized necking.

Strain (injury)

Mohr–Coulomb theory

10.2139/ssrn.4596532

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High Temperature Stress Rupture Strength of Superalloy GH4169 Inertia Friction Welded Joint

Deleted Journal (2003)

Jun Yang

The high temperature stress rupture strength was analyzed for welding state and welding+aging state of the inertia friction welded joints of direct aging state and solid solution state superalloy GH4169 by Vickers hardness, SME and TME. The research result shows that the Vickers hardness of the both alloys is softened when they are at the welding state, but the hardness will change into an even value when the joints have the post welding aging treatment(PWAT), and it is the highest hardness in the weld. The result of high temperature stress rupture strength shows that both of the PWAT alloys have typical tough fracture, and for high temperature stress rupture strength the best is the welding+aging state of direct aging state superalloy GH4169 inertia friction welded joint, and the high temperature stress rupture strength time is longer than the direct aging state superalloy GH4169 matrix.

Friction Welding

Vickers hardness test

Source

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Characteristics of Transformation and Low-temperature Deformation of Ti-51.1Ni Shape Memory Alloy

Rare Metal Materials and Engineering (2017)

Jun Yang Bi Zongyue Lei Tian Jingli Wang Liu Haizhang

R-Phase

Atmospheric temperature range

Pseudoelasticity

10.1016/s1875-5372(17)30166-2

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Mensuration on the oxygen consumption rate and asphyxiantion point of Chalcalburnus chalcoides aralenesis

Shuichanxue zazhi (2007)

Jun Yang

The method of respiratory chamber has been applied to study oxygen consumption rate and asphyxiation point ofChalcalburnus chalcoides aralenesis,and the diurnal variation curves of oxygen consumption.The results demonstrated that under the controlled temperature 16～30℃,the oxygen consumption rate and asphyxiation point increase as temperature rose,and decrease as body weight increased.The linear regression relationships of oxygen consumption rate and temperature can be described as R=0.028T~0.312(R=0.845),the relationship between oxygen consumption and body weight is R=0.6548W-0.21(R=0.974).The average oxygen consumption rate is 0.3137mg/g.LThe lowest oxygen consumption rate appears at 11∶00 and the highest at 6∶00.

Consumption

Source

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Accelerating the Layup Sequences Design of Composite Laminates via Theory-Guided Machine Learning Models

Polymers (2022)

Zhenhao Liao Cheng Qiu Jun Yang Jinglei Yang Lei Yang

Experimental and numerical investigations are presented for a theory-guided machine learning (ML) model that combines the Hashin failure theory (HFT) and the classical lamination theory (CLT) to optimize and accelerate the design of composite laminates. A finite element simulation with the incorporation of the HFT and CLT were used to generate the training dataset. Instead of directly mapping the relationship between the ply angles of the laminate and its strength and stiffness, a multi-layer interconnected neural network (NN) system was built following the logical sequence of composite theories. With the forward prediction by the NN system and the inverse optimization by genetic algorithm (GA), a benchmark case of designing a composite tube subjected to the combined loads of bending and torsion was studied. The ML models successfully provided the optimal layup sequences and the required fiber modulus according to the preset design targets. Additionally, it shows that the machine learning models, with the guidance of composite theories, realize a faster optimization process and requires less training data than models with direct simple NNs. Such results imply the importance of domain knowledge in helping improve the ML applications in engineering problems.

10.3390/polym14153229

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Discussion on Section Construction Techniques for Continuous Bridge of Large-Span Concrete

International Conference on Optoelectronics and Image Processing (2010)

Jun Yang

During constructing bridges, it is very important to select a correct method. According to the natural environment, construction conditions and social environment, selecting a reasonable job practice will bring about yield good economic returns for constructing bridges. Combining with the characteristic of big span continuous concrete bridge, this paper proposes four sorts of methods on section construction technique of big span continuous concrete bridge. They are cantilever construction method, span by span construction method, bit by bit construction method and propulsion construction method. Each method has its characteristic. On the basis of detailed discussing these four methods, the paper compares their advantages and disadvantages and their scope of application, draws some useful conclusions. Such as, the cantilever construction method can’t use bear frame. So, it can often be used where road crosses channel or other highway. Span by span construction method can locate prestressed reinforcement at the suitable site and can save high-strength material, etc. This paper supplies some useful reference for bridge construction and design.

Bridge (graph theory)

Rigid frame

Section (typography)

Prestressed concrete

Scope (computer science)

10.1109/icoip.2010.261

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Structural Response of Double-Layer Steel Cylinders under Inside-Explosion Loading

Applied Sciences (2023)

Xuejun Qin Jun Yang Junyi Guan Zhen Liao Yanjun Ma

The research on the structural response of explosive vessel is an important basis for the design of explosive vessels. Double-layer cylinder structures are widely used in the design of various explosive vessels. This paper studied the deformation of a steel cylindrical shell under internal explosion and proposes a new method for measuring shell deformation by PDV (photonic Doppler velocimetry). We carried out many spherical explosive experiments and obtained useful results that show displacement of the double-layer cylinders and the explosion time. The above process is a simulated LS-DYNA with a finite element numerical simulation. The vibration period of the outer cylindrical shell and the time for reflection of the stress wave in the outer cylindrical shell were obtained by numerical simulation and PDV measurement, respectively. The results of both can be verified against each other. Through the above research, the structural response of the multilayer cylinders can be obtained, which can provide further help with research of the structural design of multilayer cylinders.

Reflection

10.3390/app13020709

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