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Support insert run-flat tire is a kind of safety tire based on common tire structure. It has the advantages of simple structure, easy disassembly and strong bearing capacity. However, when driving under zero-pressure condition, it can not meet the requirements of heavy load, high mobility and long-distance. Aiming at this problem, the finite element model is established. The load and contact patch characteristics of the model are simulated by ABAQUS. The radial stiffness curve and the contact pressure distribution under zero-pressure are obtained. The results show that the radial stiffness curve presents a certain nonlinearity in the sidewall loading stage. When the insert contacts the tire, it is approximately linear. The contact pressure distribution cloud diagram under zero-pressure condition shows that there is warpage. The tire test bench was set up and the relevant test scheme was formulated. The radial stiffness curve and the footprint of the support insert run-flat tire under zero-pressure condition were obtained. The research results show that the simulation and test results are in good agreement. This research is of great significance to the performance analysis of whole support insert run-flat tire under zero- pressure condition. [ABSTRACT FROM AUTHOR]

In order to research the new integrity evaluation technology of gas pipeline and promote the mature development of gas pipeline integrity management, this paper deeply analyzes the characteristics of Beijing gas pipeline and combines with the methods of finite element modeling, statistical analysis, mathematical fitting and experimental verification. Based on the Spangler-lowa method, the load effects of gas pipelines with different pressure grades are analyzed, a new method for evaluating the external load carrying capacity of gas pipeline with local corrosion defects was developed, and a method for evaluating the internal pressure carrying capacity of gas pipeline was determined. The research shows that the integrity structure evaluation of gas pipeline should be evaluated according to the pressure level. Medium- and low-pressure gas pipeline is mainly affected by external load, and deformation is the evaluation basis. The sub-high-pressure gas pipeline is affected by both external load and internal pressure, and its deformation and stress are taken as the evaluation basis respectively. High-pressure gas pipeline is mainly affected by internal pressure, and stress is the evaluation basis. [ABSTRACT FROM AUTHOR]

Circuit breakers are one of the most widespread electrical devices in control and distribution systems that use electric energy fluxes, providing protection from short circuits and current overloads. First and foremost, circuit breakers should provide a high operation speed at shutdown, which can be achieved with low weight and significant electromagnetic forces. For approximate determination of magnetic system dimensions, network analysis methods are used. In addition, the model of magnetic field structure can be substantially simplified. The conductivity of air gaps between the ferromagnetic elements of a magnetic system can be described by a modified method of probable paths of magnetic flux, and the resistance of ferromagnetic elements (magnetic potential drop) is taken into account by means of a mathematically expressed magnetization curve (for steel of 10895 grade). [ABSTRACT FROM AUTHOR]

The static magnetization curves and load characteristics of dc single-winding plunger shell-core magnet system with a flat cylindrical pole have been determined using the FEMM software environment. The methods of similarity theory and experiment planning have been used to represent these characteristics as the generalized polynomial nondimensional models in the form that is convenient for solving the synthesis problems. The limit of linearity of the magnet system has been defined. [ABSTRACT FROM AUTHOR]

A computer model is used to assess the influence of the transmission coefficient and time constant of the control system on the load characteristic of a high-frequency AC welding inverter. [ABSTRACT FROM AUTHOR]

Results of theoretical and experimental investigations of a new type of a welding inverter, namely, an ac inverter welding apparatus with a frequency of 25-50 kHz, are given. A schematic circuit of the inverter power part is described, and recommendations of enhancing the safety of operation modes are given. [ABSTRACT FROM AUTHOR]