Analytical Calculation Model of an Induction Machine with Combined Star-Delta Windings and Analysis of Possible Connections

Author(s):  
C. Alteheld ◽  
R. Gottkehaskamp ◽  
A. Mockel
Author(s):  
Florian Franke ◽  
Michael Schwab ◽  
Uli Burger ◽  
Christian Hühne

AbstractIn addition to the well-known threats of bird and hail strikes, small unmanned aerial vehicles (sUAV) pose a new threat to manned aviation. Determining the severity of collisions between sUAVs and aircraft structures is essential for the safe use and integration of drones in airspace. A generic analytical calculation model needs to be developed to supplement the existing test and simulation data. This paper presents an analytic model for drone collisions with perpendicular and inclined targets. The targets have a rigid or elastic material behavior. The aircraft impact model, which is used for the design of nuclear reactor structures, is transferred and adjusted for sUAV impacts to calculate the impact force. A mass- and a burst load distribution are needed as input parameters. Both distributions are determined for an sUAV design depending on the flight direction. Compared to previous calculations, the new approach is to consider a moving target structure, which produces more realistic results. We compare the calculation results with simulation data from sUAV collisions with a commercial airliner windshield from the literature. The calculations show plausible results and a good agreement with literature data. Subsequently, the influence of the input parameters on the impact force is investigated. We see that spring stiffness, target mass, burst load distribution and damping have minor influence on the overall impact force. The impact velocity, mass distribution and flight orientation on the other hand have a major influence on the impact force. Further tests are needed to validate the impact model.


Author(s):  
Ruxin Lu ◽  
Wencheng Tang

The temperature has a great contribution to the mesh stiffness and backlash of the gear pair. Presence of thermal deformation caused by temperature will complicate the gear teeth interaction. In this paper, the thermal time-varying stiffness model and thermal time-varying backlash model are proposed with the consideration of tooth profile error and total thermo-elastic deformation consists of the teeth deformation, teeth contact deformation, and gear body-induced deformation. The key parameters of thermo-elastic coupling deformation affected by temperature are calculated. Based on the proposed models, the influencing mechanism of temperature on the tooth profile error, mesh stiffness, total deformation, and backlash are revealed. The effects of shaft radius and torque load on the thermal stiffness and thermal backlash are studied. The proposed thermal stiffness and backlash calculation model are proven to be more comprehensive and the correctness is validated.


Author(s):  
Laurent Paumier ◽  
Daniel Averbuch ◽  
Antoine Felix-Henry

In the design of flexible pipelines for offshore field developments, the determination of the pipe resistance while subjected to external pressure and bending is very important in deepwater and is now required by the ISO and API standards. One of the critical failure modes being associated with this type of loads is the hydrostatic collapse. The collapse value of flexible pipe is calculated with a model validated with over 200 tests performed on all possible pipe constructions. This model has an analytical basis, and has been established in the past, leading to a fast and straightforward use. In order to address the bent collapse failure mode, Technip and IFP have therefore developed and improved over the past few years an analytical calculation model, based on the collapse model for straight pipes. The purpose of this paper is to present this design methodology and its validation. The modelling principles of the collapse calculation of straight flexible pipes are firstly presented, along with the main hypotheses. The adaptation to the case of curved pipes is detailed in the sequel of the paper. Many types of flexible pipe samples have been tested up to collapse both in straight and curved configurations. The results of these tests have been used to validate this model. In the paper, several tests results will be presented and compared with the calculations. This model is effective, of straightforward use, and has been certified by a third party. It allows Technip to optimize the flexible pipe design in particular for ultra-deep water applications, where external pressure resistance is very important.


Author(s):  
Bing Chen ◽  
Lijie Zhang ◽  
Zhanzong Feng ◽  
Yuanyuan Du ◽  
Wei Mo ◽  
...  

During the running of high-speed tracked vehicles, the energy loss due to the rotation and tension-compression deformation of the rubber bushing between the track pin and the track plate causes the largest proportion of energy consumption in tracked vehicle propulsion systems; therefore, it is critical to study energy consumption of this component as it is the largest amount of energy loss of the system. First, the theoretical modeling and analysis of the torsional hysteresis and the tension-lag of the hanging glue on the pin of the track pin are conducted. Both energy loss of torsional hysteresis and energy loss of the hysteresis of tension and pressure are obtained when the rubber bushings pass the sprocket, the road wheel, and the idler. Second, a new and novel rubber bushing model based upon the rubber bushing elastic element, the friction element, and the viscoelastic element is proposed. Then the parameters (such as the static elastic stiffness and the maximum friction) of each unit are identified according to the dynamic characteristic experiment. Finally, the numerical simulation results of MATLAB with different stiffness and damping coefficient in addition to tension and compression energy consumption under different frequencies are obtained, and the comparisons are basically consistent with the experimental results; the average errors are less than 8%. The present analytical calculation model is practically useful and can meet the requirements of engineering applications.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Michał Grodecki

Abstract The paper presents results of a numerical investigation on load capacity of the mixed bench and slab shallow foundations (often used in the process of the modernization of the old, antique buildings, which are suffering from lack of the load capacity). The main trouble with use of existing analytical approaches is a non-unique foundation level of the bench and slab, they could even be founded on different geotechnical layers. Proposed analytical model based on Brinch Hansen (EC-7) approach could deal with such a problem. Results of 2D and 3D numerical modelling (ultimate load of the foundation) are compared to the obtained by using the proposed approach. Influence of the soil above the foundation level is also investigated. Different width to length ratios of the foundation are analyzed (from “short” to “long” foundations). Usability of the proposed analytical model in engineering practice is proved by numerical simulations; the obtained results are on the safe side with quite acceptable margin of additional safety.


2020 ◽  
Vol 146 (2) ◽  
pp. 04019206 ◽  
Author(s):  
Reignard Tan ◽  
Max A. N. Hendriks ◽  
Mette Geiker ◽  
Terje Kanstad

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