FEA model based cautious automatic optimal shape control for fuselage assembly

In a half fuselage assembly process, shape control is vital for achieving ultra-high precision assembly. To achieve better shape adjustment, we need to determine the optimal location and force of each actuator to push and pull a fuselage to compensate for its initial shape distortion. The current practice achieves this goal by solving a surrogate model based optimization problem. However, there are two limitations of this surrogate model based method: (1) Low efficiency: Collecting training data for surrogate modeling from many FEA replications is time-consuming. (2) Non-optimality: The required number of FEA replications for building an accurate surrogate model will increase as the potential number of actuator locations increases. Therefore, the surrogate model can only be built on a limited number of prespecified potential actuator locations, which will lead to sub-optimal control results. To address these issues, this paper proposes an FEA model based automatic optimal shape control (AOSC) framework. This method directly loads the system equation from the FEA simulation platform to determine the optimal location and force of each actuator. Moreover, the proposed method further integrates the cautious control concept into the AOSC system to address model uncertainties in practice. The case study with industrial settings shows that the proposed Cautious AOSC method achieves higher control accuracy compared to the current industrial practice.

Анализ экситонной люминесценции в мезорезонаторах на основе GaN

We considered the interaction of an exciton mode with photonic eigenmodes in a GaN structure with several μm in size. A technique for obtaining spectra from such structures is demonstrated. The most optimal shape and dimensions of the resonator were selected for effective interaction of light and matter. The theoretical spectrum for the selected resonator is obtained and analyzed.

Research on the influence of the clamping devices on the size of the perforated holes in long round pipes

When perforation by cold plastic deformation processes of long round pipes, the technological problems appear primarily at the deformation of the part section, in the perforation area by losing the stability of the part, in the case of holes made at a distance from the pipe ends. The purpose of the research was to determine the influence of the constructive shape of the pipe clamping devices in the perforation area, in order to determine the device that offers the best stability of the section, to allow obtaining possible holes as large in diameter. The research was based on the application of materials strength methods and the Castigliano method of solving the indeterminacy, related to the process of cold plastic deformation. The research materialized by determining some calculation relations and specific diagrams regarding the diameter’s variation of the perforated holes in the air environment, depending on the dimensions of the part and the mechanical characteristics of the part material, for different forms of clamping devices. The calculations were performed considering that the perforation is performed in air, with a punch applied from the outside of the considered piece. The calculation relations and the obtained diagrams allow the determination of the maximum orifices, for certain dimensions of the pipes and for different mechanical characteristics of the part material. At the conclusions, a comparison was made of the results obtained for the variants of clamping considered devices and the optimal shape of the device was established, which allows the making of the largest perforated holes in the part.

Awareness and Use of Current Sports Injury Prevention Programs among Physiotherapists Worldwide

Purpose. Physiotherapists are trained to prevent, assess, and rehabilitate all kinds of injuries including sports injury. The goal of the physical therapist should be making sure that the athlete is in optimal shape to perform, with a minimal risk for developing an injury. This study aims to assess the physiotherapists’ awareness, implementation, and views of sports injury prevention programs (IPPs) from an international perspective. Materials and methods. A self-administered questionnaire was developed and distributed to physiotherapists worldwide through World Physiotherapy member organizations. The study targeted physiotherapists at an international level. The study included 484 participants, of whom 44.4% were male and 55.6% were female physiotherapists. Results. A total of 287 (59.3%) of the participants were aware of the current sports IPPs, 177 (36.6%) were implementing sports IPPs in their current practice. Participants who implemented the sports IPPs reported a positive opinion about the program efficacy, with a score of 7.3 ± 2.11 out of 10. Conclusions. Globally, physiotherapists have average awareness and low implementation levels of IPPs. Physiotherapists showed a positive score regarding the effectiveness of IPPS, especially the KIPP and the iSPRINT.

Shapes’ optimisation using numerical naval hydrodynamics of a Ro-Ro double ferry with electric propulsion to cross the Danube

One of the crucial problems of the 21st century is pollution. Regarding a low carbon footprint, thorough research efforts are being made to minimise fuel gas emissions. Ships, through the powers established for propulsion and the fossil fuels used, are some of the most toxic human inventions. Scientist in many European countries and beyond are developing studies either to reduce emissions from propulsion engines or to design body shapes of ships with low forward resistance and to find electric propulsion solutions. This paper carries out studies of naval hydrodynamics to find body shapes that generate the lowest resistance to advance. Thus, using hydrodynamic observations and with the help of the NUMECA calculation program, two different hulls are studied in order to establish the optimal shape with the lowest forward resistance. Furthermore, acknowledging the limited aquarium of the inland waters, an important aspect to approach is the size of the waves as well as their length. In order not to cause damage to existing shores and facilities, the waves produced by the floating body must have minimum heights and wavelengths.

Existence of an optimal domain for the buckling load of a clamped plate with prescribed volume

We formulate the minimization of the buckling load of a clamped plate as a free boundary value problem with a penalization term for the volume constraint. As the penalization parameter becomes small, we show that the optimal shape problem with prescribed volume is solved. In addition, we discuss two different choices for the penalization term.