The dynamic behavior of the railgun housing including the rails is of great importance for the system performance. The transient loading (magnetic pressure) may have a negative influence on the sliding electrical contact required for this acceleration technology. Therefore, the analysis of the displacement of the inner rail surfaces due to elastic waves is of great importance. The French-German Research Institute of Saint Louis (ISL) is operating several railguns with housings characterized by an open barrel design allowing for innovative diagnostic techniques. The repelling forces between the rails are countered using discrete steel bolts. The rails are mounted to bars made from composite material. In the past, we presented the experimental and numerical findings concerning the dynamic behavior of such railguns in single shot mode. In this paper, we present for the first time 3-D finite element calculations concerning the dynamical behavior of the ISL RApid FIre RAilgun operating in multishot mode. Multishot scenarios with fire rates of 50 Hz are considered and particular attention is paid to the question if the dynamical behavior of the railgun is influenced by preceding shots.
IndexTerms-3-D model, finite-element method, multishot, open barrel, railgun, transient dynamics.
One vital component in the flexo inking system of high-line screen engrav-ing technologies is anilox rollers. These deliver a precise and consistent amount of ink during the process of flexography, making it possible to produce high-resolution prints of exceptional quality. However, as print quality continues to improve, printing houses are experiencing more fre-quent problems with anilox rollers, such that ink transfer during printing operations is being unpredictably reduced. Due to the lack of research into anilox rollers there is insufficient objective information on how to maintain them at peak performance and condition. This study investigates the clogging of anilox roller cells (without assessing cell wear) in a num-ber of printing houses in the Baltic States. Cell clogging of anilox rollers was determined depending on cell size, ink type and washing method.
Background: Today, animals, like humans, suffer from spinal illnesses, which are aggravated in old age. Much emphasis is placed on diagnosis and treatment, but little focus is given to the spine's mechanical properties. Degenerative spine diseases are a major problem throughout the world. According to the World Health Organization, osteoporosis is a world-class public problem that reduces bone mass, resulting in bone fracturing and increased risk of bone fracturing. Therefore, the mechanical investigation of vertebrae can provide more information about the development of osteoporosis.
Case Description: For our case report, we used spayed mongrel lumbar vertebrae samples obtained from a canine which was about 8 years old and weighed 28 kg. The dog was diagnosed with a mammary tumour, and the dog’s owners decided to euthanise the dog. All consent forms were filled.
Conclusions: Mechanical tests were performed on three vertebrae, and a noticeable difference was observed in the first cycle of the first vertebra (L1). Second-order polynomials for displacement and seventh-order polynomials for pressure were proposed for describing the stress–strain relation of the vertebrae under the cyclical loads.
Our research protocol has been broken down into several parts. After measuring the area of the loaded surface, the largest area was in the L2 vertebra (176 mm ± 16; 177 mm ± 3 mm), and the smallest was in the L7 vertebra (156 mm ± 4 mm; 151 mm ± 33 mm). The smallest distance was recorded between the first (L1) and seventh (L7) lumbar vertebrae (L1) (15.17 mm ± 0.93 mm), and the largest distance was recorded between the L3 and L4 vertebrae of the lumbar (19.8 mm ± 3.7 mm).
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