The fracture toughness test of low constraint specimens is of great significance for the safe operation of oil and gas pipelines. In this paper, the existing fracture toughness testing methods and the development process of low constraint specimens are reviewed, and the common fracture toughness characterization parameters such as crack tip opening displacement (CTOD) and J-integral are introduced. The key problems such as the stress intensity factor, the J-integral plasticity factor, the J-integral and CTOD conversion factor, the crack size measurement method, and the digital image correlation method, in the fracture toughness test, are analyzed, and the problems that need to be further studied are summarized, to provide a necessary basis for the development of fracture toughness test of low constraint specimens.

In order to improve the safety of heavy-duty vehicles in the steering process, this paper proposes an active front wheel steering control strategy based on the sliding mode variable structure control. With this strategy in mind, an active steering controller is designed. A simplified vehicle dynamics model with two degrees of freedom and a model for a three-axle commercial vehicle are established. The co-simulation platform is built with TruckSim and Simulink, and the hardware-in-loop experiment is carried out. Under different working conditions and at different speeds, the steering stability analysis of the vehicle with or without the active steering controller is carried out. Based on this, the sensitivity analysis of the active steering influencing factors of the sliding mode variable structure control is carried out. The experimental results show that this controller strategy has a good adaptability under different working conditions.

With a finite element model, the dynamic response of the catenary riser of deep-sea mining systems under the action of the ocean current and the motion of the surface vessel is simulated. The results show that the maximum equivalent stress and the maximum displacement of the catenary riser change periodically with a phase difference of half a period between them. When the surface vessel moves to the highest position, the displacement of the catenary riser reaches the maximum. The maximum equivalent stress and the maximum displacement of the catenary riser increase with the increase of the displacement amplitude of the surface vessel and decrease with the increase of the period. In addition, the effect of the displacement and the period of the motion of the surface vessel on the equivalent stress of the catenary riser is greater than that on the displacement.

In the mechanics education, it is urgently needed to enhance the qualities of students in solid foundation and creative ability. Even though the enhancement has been widely recognized in the Chinese circle of mechanics education, some problems remain open in practice. Based on the talent development law, the cognitive learning law and the practice innovation law, three problems are analyzed, including the curriculum optimization, the design and development of teaching materials, and the innovation in practice, and the corresponding suggestions are made. Among them, some have been validated to be possible solutions in practice.

This paper reviews the process of exploration of the wing lift theory in the late 19th and early 20th centuries. It includes Newton's sine-square law, the understanding and application of the Magnus effect, Lanchester, Kutta, and Joukowsky's establishment of the wing lift circulation theory and Prandtl's establishment of the lift line theory. The historical facts are traced with stories about related scholars.

Based on some historical documents, this paper briefly reviews the development of the Department of Water Conservancy of Peiyang University (Tianjin University), with related events and persons. This paper focuses on the historical continuity of the water conservancy discipline and the Department of Water Conservancy from Peiyang University to Tianjin University and its position in the Chinese higher education of water conservancy; the role of Peiyang University in Chinese First Institute of Hydraulic Engineering and its development process; and the related stories of the Centre of Hydraulic Engineering, famous professors and the outstanding alumni, and shows the historical inheritance and the modernisation achievements of the Department of Water Conservancy of Peiyang University-Tianjin University in the past one hundred and twenty-five years, which inspire a new generation of Tianjin University in water conservancies. Rejuvenate the spirit of Peiyang, and deeply remember the late, outstanding alumni Yu Yuanjun and others.