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Tytuł:
Science and practice of core stability and strength testing
Autorzy:
Zemková, Erika
Powiązania:
https://bibliotekanauki.pl/articles/1923682.pdf
Data publikacji:
2018-09-19
Wydawca:
PPHU Projack Jacek Wąsik
Tematy:
core muscle tests
lifting task
muscle power
torsional tests
trunk rotations
Opis:
This study deals with a gap between science and practice in the testing of core stability and strength and presents our approach to solving this issue. Typical core stability tests require the subject to maintain a neutral spinal posture while under load in a quadrupedal or supine position and assess the endurance of global core muscles. However, most of these non-dynamometric tests have been developed for use in clinical and research settings. A suitable alternative represents torsional tests performed under stable or unstable conditions and instrumented tests in the form of trunk repositioning and load release tasks. Core strength is measured in terms of how much weight can be lifted, how many repetitions can be performed, or how long a neutral stable position can be maintained. In the laboratory, isometric and isokinetic dynamometers are frequently used. Isometric strength measurements are usually recommended as a standard for lifting tasks. However, such measurements underestimate the loads on the spine during dynamic movement. A deadlift to high pull exercise that involves working major muscle groups in the upper and lower body may best simulate the demands of jobs comprising of lifting tasks. Furthermore, isokinetic loading does not occur in daily human activities and is not specific to the requirements of sports. Given that rotational power is a better predictor of athlete performance, the test adapted from the wood chop exercise on a weight stack machine may provide conditions imposed by sports. One can also use a system that allows evaluation of muscle power during seated or standing trunk rotations with a barbell placed on the shoulders. These tests utilizing portable diagnostic systems may be implemented in functional diagnostics for athletes and sedentary or manual workers whose activities involve lifting tasks or trunk rotations under unloading or loading conditions; so complementing existing testing methods.
Źródło:
Physical Activity Review; 2018, 6; 181-193
2300-5076
Pojawia się w:
Physical Activity Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acute effects of core stability exercises on balance control
Autorzy:
Szafraniec, R.
Barańska, J.
Kuczyński, M.
Powiązania:
https://bibliotekanauki.pl/articles/307089.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
stabilność postawy
posturografia
mięśnie tułowia
postural stability
motor learning
posturography
balance training
trunk muscles
sway entropy
Opis:
The aim of this study was to investigate whether a single bout of core stability exercises improves body balance immediately after the bout of exercise and during a retention test. Methods: The study involved 16 women (age 22–25 years, body weight 60.5 ± 5.2 kg, height 166 ± 5.4 cm). Postural stability was assessed in the mediolateral (ML) and anteroposterior (AP) planes separately on a force plate (Kistler 9286 AA) during quiet standing on a soft support surface with the eyes closed. Subjects were measured 4 times: just before (T0), 1 minutes after (T1 m), 30 minutes after (T30 m), and 24 hours after the workout (T24 h). Postural balance was evaluated by five parameters based on the center of pressure (COP) signal: variability (VAR), mean velocity (VEL), sample entropy (ENT), frequency (FRE), and fractal dimension (FRA). Results: We observed a decrease in VAR and VEL in the ML plane at T30 m and T24 h, compared to T0. The COP entropy significantly increased in the ML plane at T24 h, compared to T0. Conclusions: A single bout of core stability exercises improved the control of the mediolateral body balance. This effect was evident within 30 minutes after exercise, and remained for at least 24 hours. In addition, 24 hours after exercise we observed an increased automaticity in the strategy to maintain a stable upright stance.
Źródło:
Acta of Bioengineering and Biomechanics; 2018, 20, 3; 145-151
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Efficacy of dynamic Swiss ball training in improving the core stability of collegiate athletes
Autorzy:
Nuhmani, Shibili
Powiązania:
https://bibliotekanauki.pl/articles/1925615.pdf
Data publikacji:
2021-01-20
Wydawca:
PPHU Projack Jacek Wąsik
Tematy:
core training
dynamic exercises
athletic rehabilitation
sports training
Opis:
Introduction: The training of core muscles is key in sports training to improve performance and reduce the risk of injuries. However the most effective method to improve core musculature is still controversial. Therefore the objective of this study was aimed at investigating the effectiveness of dynamic Swiss ball training in reinforcing the core stability of collegiate athletes. Materials and methods: This two-group, two-factor research involved 67, 18- to 28-year-old collegiate athletes (18 females, 49 males) who were divided into experimental and control groups. The experimental group was provided dynamic Swiss ball training, whereas the control group was instructed to perform floor exercises. The groups underwent training for six weeks (three days per week). Four core stability tests (the Biering-Sorenson trunk extension, Side Bridge, prone bridge, and double leg lowering tests) were administrated pre- and post-training. Results: The mean scores of the participants in the core stability tests significantly improved after six weeks of training (p<0.05), but the between-group comparisons revealed that the experimental group significantly outperformed the control group in terms of enhancement in core stability (p<0.05). Conclusion: The relatively high improvement in core stability parameters after Swiss ball training suggested that these exercises are favorable alternatives to traditional floor exercises in strengthening the core muscles. The findings are expected to help athletes, coaches, trainers, and other strength and conditioning specialists involved in athletic training decide on appropriate training methods.
Źródło:
Physical Activity Review; 2021, 1, 9; 9-15
2300-5076
Pojawia się w:
Physical Activity Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Core Stability and Functional Exercises on Selected Speed and Strength Parameters in Expert Female Footballers
Autorzy:
Niewolna, Natalia
Zwierko, Teresa
Powiązania:
https://bibliotekanauki.pl/articles/1054673.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet Szczeciński. Wydawnictwo Naukowe Uniwersytetu Szczecińskiego
Tematy:
core stability
football
functional training
motor effects
Opis:
Designed to strengthen the deep (stabilizer) muscles which stabilize joints and ligaments, core stability exercises are important for the development of motor skills in athletes. In this research, we aimed to determine how a two-year program of core stability and functional exercises influenced the strength and speed of female football players. The tested athletes (n = 17) were members of Olimpia Szczecin MKS, a first division football club from Poland. Their mean age was 19.8 ±1.4 years, while the mean duration of sport experience was 6 years. We analyzed their running speed, as well as the maximal strength of eight major muscle groups: rectus abdominals, abdominal oblique, shoulder girdle, chest, upper limbs, quadriceps, biceps and gastronomies. The effects of training on motor speed and strength were measured twice, prior to each of the two seasons. The functional training resulted in significant changes in the strength of various muscle groups: quadriceps (Δ17.1 kg; p < 0.05), abdominal oblique muscle (Δ9.1 kg; p < 0.05), shoulder girdle (Δ3.6 kg; p < 0.05) and chest (Δ3.5 kg; p < 0.05). There was also a significant reduction in the time of the 30 meter sprint (p < 0.05) (Δ0.1 s; p < 0.05). In summary, functional training had a positive effect on the strength and running speed of the tested female footballers.
Źródło:
Central European Journal of Sport Sciences and Medicine; 2015, 12, 4; 91-97
2300-9705
2353-2807
Pojawia się w:
Central European Journal of Sport Sciences and Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stability Training and Effectiveness of Playing Basketball
Autorzy:
Worobel, Mateusz
Powiązania:
https://bibliotekanauki.pl/articles/1030893.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Szczeciński. Wydawnictwo Naukowe Uniwersytetu Szczecińskiego
Tematy:
basketball
core stability
free throw
trunk control
Opis:
The aim of this study is to review the available literature for factors affecting a basketball throw and the stabilization of the trunk. Searching for the most important elements which ought to be improved during training to increase the effectiveness of a throw and those which condition the correct stabilization of the trunk. The obtained results, after analyzing the literature, show that it is not possible to determine a single factor affecting a throw and the stabilization of the trunk. There are many factors that influence each other and, therefore, must be trained as one. There are biomechanical relationships between the effectiveness of making a throw, the positioning of the limbs, the trunk and the trajectory of the ball. It is important to mention the role of a factor outside biomechanics, such as the player’s psyche. Muscles have the greatest impact on stabilization. Muscle function would not be possible without proper control by the nervous system The conclusion section shows a large number of interacting factors responsible for the quality and effectiveness of the throw as well as for the stabilization of the trunk. This allows better planning and conducting of basketball training aimed at improving technique and throw effectiveness.
Źródło:
Central European Journal of Sport Sciences and Medicine; 2020, 30, 2; 85-95
2300-9705
2353-2807
Pojawia się w:
Central European Journal of Sport Sciences and Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Efficacy of Exercise Protocols on Balance in Badminton Players -A Systematic Review & Meta-Analysis
Autorzy:
Indora, Nitin Kumar
Manoj, Malik
Jaspreet, Kaur
Powiązania:
https://bibliotekanauki.pl/articles/2170348.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Szczeciński. Wydawnictwo Naukowe Uniwersytetu Szczecińskiego
Tematy:
badminton
core stability training
Pilates
Plyometric
Swiss ball
core strengthening
balance
Opis:
Objective. the goal of this “systematic review” and meta-analysis is to find out the efficacy of exercise regimes on balance in badminton players. Study design. Systematic review and meta-analysis. data Source. Pub Med, “Cochrane database (Cochrane Central register of controlled Trials)”, google Scholar, Springer, and DoAJ. Eligibility criteria. limits were applied to database searches to identify papers published in English and only human studies were included. results. result of Meta – analysis was statistically significant in “anterior component of Y-balance test” (MD = 2.39, 95% ci = 1.90, 2.89; “p ≤ 0.00001”) with low heterogeneity (i² = 0%, p < 0.41). There was statistically significant improvement in postero-medial component of y- balance (MD = 2.87, 95% ci = 0.55, 5.19; p ≤ 0.02) with “moderate heterogeneity” (i² = 39%, p < 0.19). result showed statistically significant improvement in postero-lateral component of y- balance test (MD = 3.09, 95% ci = 0.64, 5.65; p ≤ 0.02) with “moderate heterogeneity (i² = 38%, p < 0.20)”. There was “statistically significant “improvement in overall balance of y-balance test in “experimental group as compared to control group (MD = 8.49, 95% ci = 4.62,12.36; p ≤ 0.0001) with low heterogeneity (i² = 0%, P < 0.47)”. Conclusion. this systematic and meta-analysis concluded that various exercise protocols may result in improvement in the balance of badminton players. PrOSPErO registration number: crD42020193620.
Źródło:
Central European Journal of Sport Sciences and Medicine; 2022, 40; 61-76
2300-9705
2353-2807
Pojawia się w:
Central European Journal of Sport Sciences and Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of Two 12-week Strengthening Programmes on Functional Mobility, Strength and Balance of Older Adults: Comparison between TRX Suspension Training versus an Elastic Band Resistance Training
Autorzy:
Gaedtke, Angus
Morat, Tobias
Powiązania:
https://bibliotekanauki.pl/articles/1054907.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Szczeciński. Wydawnictwo Naukowe Uniwersytetu Szczecińskiego
Tematy:
TRX suspension training
core stability
healthy older adults
intervention
sling exercise training
Opis:
No study has compared sling exercise training with elastic band resistance training in healthy older adults. Therefore, the purpose of this study was to determine whether different effects on functional mobility, strength and balance ability were produced by using different devices (sling trainer and elastic bands). Twenty-four participants were assigned to two different training groups, INT (TRX-OldAge) and CON (elastic bands). Participants trained three times per week for 30 minutes for 12 weeks. The Multisurface Obstacle Test for Older Adults (MSOT) and the 1-repetition maximum test using the chest press and the leg press were performed to assess functional mobility and dynamic strength, respectively. To examine balance ability, data of body-worn sensors and a force plate measured during different standing positions have been investigated. A main time effect occurred for functional mobility (p = 0.009) with a significant improvement within INT (p = 0.044), and for the chest press (p = 0.017) with a significant improvement within INT (p = 0.019). However, there was no group-by-time interaction in any of the measured parameters. Compared to elastic band resistance training, TRX-OldAge induced similar effects on the functional mobility, strength and balance ability of healthy older adults.
Źródło:
Central European Journal of Sport Sciences and Medicine; 2016, 13, 1; 49-64
2300-9705
2353-2807
Pojawia się w:
Central European Journal of Sport Sciences and Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Changes in the contraction ratio of transversus abdominis and quality of life in patients after total hip replacement and three-compartment knee arthroplasty with implant posterior stabilization
Zmiany współczynnika aktywacji skurczu mięśnia poprzecznego brzucha oraz jakość życia u chorych po przebytej aloplastyce całkowitejstawów biodrowych i aloplastyce trójprzedziałowej stawów kolanowych ze stabilizacją tylną implantu
Autorzy:
Golec, Joanna
Nafalski, Kamil
Turzański, Damian
Masłoń, Agata
Szczygieł, Elżbieta
Czechowska, Dorota
Balicka-Bom, Joanna
Kuzaj, Artur
Golec, Edward
Powiązania:
https://bibliotekanauki.pl/articles/1790963.pdf
Data publikacji:
2018-08-03
Wydawca:
Akademia Wychowania Fizycznego im. Bronisława Czecha w Krakowie
Tematy:
Core stability
m. transversus abdominis
Rehabilitative Ultrasound Imaging (RUSI)
Stabilizacja centralna
mięsień porzeczny brzucha
fizjoterapeutyczne obrazowanie ultrasonograficzne
Opis:
Core stability is a reference term for the performance of the deep trunk muscles, which provide functional stability of the lumbopelvic area and control the human body in static and dynamic positions. The study group consisted of 30 patients between the age of 42 and 76 years (mean=61.4) after total hip arthroplasty (total hip replacement, Group I) and total knee arthroplasty (three-compartment arthroplasty with posterior stabilization of the implant - Group II). In 18 (60%) patients, hip endoprosthesis was performed, whereas in 12 (40%), three-compartment knee endoprosthesis with posterior stabilization has been implanted. In the study group, Rehabilitative Ultrasound Imaging (RUSI) of the transversus abdominis muscle thickness was conducted at rest and in contraction, the transversus abdominis activation ratio was specified, the SF-36 Life Quality Questionnaire was applied and a three-week treatment cycle was performed. The tests were carried out twice, i.e. before and after treatment. In the group of patients after total hip replacement, the transversus abdominis (TrA) contraction ratio before the beginning of the exercise programme was 0.79±0.06, and after its completion 0.9 ±0.02. The observed difference was statistically significant at p<0.001. In the group of patients after three-compartment knee arthroplasty, the TrA contraction ratio before the beginning of the exercise programme was 0.78±0.09, and after its completion0 0.91±0.02. The difference of these values was statistically significant at the level of p<0.05. The results of the SF-36 questionnaire in both groups indicate improvement in physical functioning. The observed difference was statistically significant at p<0.001. The performed three-week physiotherapy treatment in conjunction with deep muscle training increases the thickness of the TrA muscle during rest and contraction testing, and increases the transversus abdominis contraction ratio in Rehabilitative Ultrasound Imaging in the study groups. Furthermore, improvement in the level of physical functioning was observed within the studied groups.
Wstęp: „Stabilizacja centralna” (ang. core stability) jest terminem odnoszącym się do wydolności mięśni głębokich tułowia, które zapewniają stabilność funkcjonalną okolicy lędźwiowo-krzyżowo-biodrowej oraz kontrolują ciało człowieka w pozycjach statycznych i dynamicznych. Materiał i metody: Grupę badaną stanowiło 30 chorych w przedziale wiekowym 42-76 lat (średnia 61,4 lat) po przebytej aloplastyce całkowitej stawu biodrowego (endoprotezoplastyce – Grupa I) i kolanowego (aloplastyka trójprzedziałowa ze stabilizacją tylną implantu – Grupa II). Spośród nich 18. (60%) chorych stanowiły osoby, u których implantowano endoprotezę do stawu biodrowego, 12 natomiast, (40%) endoprotezę trójprzedziałową stawu kolanowego ze stabilizacją tylną implantu. W grupie badanej wykonano fizjoterapeutyczne obrazowanie ultrasonograficzne (RUSI) grubości mięśnia poprzecznego brzucha w stanie skurczu i rozkurczu, określono współczynnik aktywacji mięśnia poprzecznego brzucha, zastosowano Kwestionariusz Jakości Życia SF-36 oraz przeprowadzono 3-tygodniowy cykl leczenia. Badania wykonano 2-krotnie tzn. przed rozpoczęciem i po zakończeniu leczenia. Wyniki: W grupie chorych po endoprotezoplastyce całkowitej stawu biodrowego współczynnik aktywacji skurczu mięśnia poprzecznego brzucha (TrA) przed rozpoczęciem programu ćwiczeń wynosił 0,79±0,06, a po jego zakończeniu 0,91±0,02. Ustalona jego różnica było istotna statystycznie na poziomie p<0,001. W grupie chorych po endoprotezoplastyce trójprzedziałowej stawu kolanowego współczynnik aktywacji skurczu TrA przed rozpoczęciem programu ćwiczeń kształtował się na poziomie 0,78±0,09, a po jego zakończeniu 0,91±0,02. Różnica tych wartości było istotna statystycznie na poziomie p<0,05. Wyniki kwestionariusza SF-36 w obu grupach świadczą o poprawie funkcjonowania w sferze fizycznej. Różnica ta była istotna statystycznie na poziomie p<0,001. Wnioski: Przeprowadzona 3-tygodniowa fizjoterapia w połączeniu z treningiem mięśni głębokich wpływa na zwiększenie grubości mięśnia TrA podczas badania w rozkurczu oraz w skurczu oraz wpływa na zwiększenie współczynnika aktywacji mięśnia poprzecznego brzucha w fizjoterapeutycznym obrazowaniu ultrasonograficznym w badanych grupach. Zaobserwowano również poprawę poziomu funkcjonowania fizycznego w badanych grupach.
Źródło:
Medical Rehabilitation; 2018, 22(2); 4-10
1427-9622
1896-3250
Pojawia się w:
Medical Rehabilitation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal Stability of Bent-Core Liquid Crystals Doped with Magnetic Nanoparticles
Autorzy:
Juríková, A.
Csach, K.
Miškuf, J.
Tomašovičová, N.
Mitróová, Z.
Závišová, V.
Koneracká, M.
Kopčanský, P.
Timko, M.
Éber, N.
Fodor-Csorba, K.
Vajda, A.
Powiązania:
https://bibliotekanauki.pl/articles/1387994.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.30.-v
64.70.mj
65.80.-g
Opis:
In the work phase transitions in bent-core liquid crystals were studied using differential scanning calorimetry. For the binary mixture of bent-core molecules with 50 wt% of rod-shaped compound, the nematic to smectic transition occured below 40°C and the crystallization temperature shifted to sub-ambient temperatures. The influence of doping of the bent-core liquid crystals with magnetic nanoparticles on the kinetics of observed phase transitions was studied. The phase transition temperatures were shifted depending on the nanoparticle type and changed with varying cooling rate for all studied liquid crystal samples.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 638-640
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of ground reaction forces during the Basic Step on the Core Board platform at various levels of stability
Autorzy:
Karczewska, M.
Madej, A.
Sadowska, A.
Mastalerz, A.
Urbanik, Cz.
Powiązania:
https://bibliotekanauki.pl/articles/306441.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fitness
biomechanika
siła reakcji podłoża
Core Board
ground reaction forces
Opis:
Purpose: The aim of this paper was to examine and compare the changes of ground reaction forces observed during the Basic Step on the Core Board fitness device at various levels of stability. Material and method: The study involved 10 female students. Participants stepped on and off the Core Board 10 times at 3 levels of stability. After completing a series of steps, the Core Board’s stability was modified and the participant repeated the whole series. The measurement platform to examine three components of the reaction force (horizontal in the sagittal and frontal planes, and vertical) was used. Results: The ground reaction force (GRF) observed on the Core Board, in the vertical and horizontal components is higher at all three levels of stability than on the platform without the device. Significant differences in GRF were observed in the horizontal component in the frontal plane (Fz) at all three levels of mobility as well as in impulse, measured on platforms with the device. Conclusion: The results on the Core Board training device present highest horizontal ground reaction forces in frontal plane at the highest level of Core Board mobility and this showing little medio-lateral stability and a more reactive way of movement regulation of the participants. As a consequence of the force patterns found it may be suggested that fitness training concepts should focus more possibly higher strains on the locomotor system most likely caused by changed ground reaction force patterns, an idea that has to be further analyzed with more complex measurement approaches.
Źródło:
Acta of Bioengineering and Biomechanics; 2016, 18, 4; 63-70
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic behaviour of three-layered annular plates with viscoelastic core under lateral loads
Autorzy:
Pawlus, D.
Powiązania:
https://bibliotekanauki.pl/articles/281720.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
sandwich plate
viscoelastic core
dynamic stability
Opis:
This paper presents the dynamic behaviour of three-layered, annular plates with a linear viscoelastic core. The annular plate is loaded in plane of facings with variable in time forces acting on the inner or outer plate edges. The analysed plate structure is symmetric and composed of three-layers: thin facings and a thicker, soft core. The core material is considered as linear with viscoelastic properties. Analytical and numerical solution will be presented including the wavy forms of dynamic loss of plate stability. In the analytical and numerical solution, two approximation methods: orthogonalization and finite difference have been applied to obtain the system of differential equations for the analysed problem of dynamic deflections of the examined plate with the viscoelastic core. Additionally, the suitable plate model using the finite element method has been built. The numerical calculations carried out in ABAQUS system show the results which are compatible with those obtained for the analytical and numerical solution. Presented in figures time histories of plate deflections and velocity of deflections as well as buckling forms of the plate model show the dynamic response of the examined plate on time-dependent loads and core material properties.
Źródło:
Journal of Theoretical and Applied Mechanics; 2015, 53, 4; 775-788
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic response of three-layered, annular plate with thick core
Dynamiczna odpowiedź pierścieniowej płyty trójwarstwowej z rdzeniem grubym
Autorzy:
Pawlus, D.
Powiązania:
https://bibliotekanauki.pl/articles/139915.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
three-layered plate
thick core
dynamic stability
płyta trójwarstwowa
rdzeń gruby
stabilność dynamiczna
Opis:
The paper presents the solutions, calculation results and dynamic observations of three-layers, annular plate with thick core subjected to increasing in time load. The presented solutions use approximate methods: orthogonalization method and finite difference method in analytical and numerical solution of the problem, and finite element method. The observed phenomenon of the reduction of critical load values of the plates, in which the buckling mode is not global and there are different additional deflections of respective plate layers was comprehensively analysed in order to evaluate the critical state and supercritical plate behaviour. The critical deformation could have a form with strong deformation in the region of the loaded plate edge. The observation of the dynamic behaviour of plates, which buckling modes have circumferential waves is an important element of the analysis. Presented in this work the analytical and numerical solution to the problem of dynamic plate deflection was generalized on the case of plates with buckling waves in circumferential direction.
W pracy przedstawiono sposób rozwiązania zagadnienia ugięć dynamicznych trójwarstwowych płyt pierścieniowych oraz liczne wyniki obliczeń numerycznych. Przedmiotem obserwacji są płyty, których rdzeń traktowany jest jako środkowa gruba warstwa. Płyta poddana jest obciążeniom liniowo narastającym w czasie działającym w płaszczyźnie okładzin na brzeg zewnętrzny lub wewnętrzny. Rozwiązanie zagadnienia dynamicznych ugięć płyty wykorzystuje przybliżone metody: ortogonalizacji i różnic skończonych. Problem rozwiązano także wykorzystując metodę elementów skończonych budując modele płyt w programie ABAQUS. Rozwiązanie umożliwia obserwację zarówno osiowosymetrycznych, jak i obwodowo pofalowanych postaci utraty stateczności płyty. Obserwacjom poddano zachowanie płyt w obszarze krytycznym i pokrytycznym. Szczegółowa analiza dotyczy tych przypadków płyt, których utrata stateczności nie ma formy globalnej, a wartość krytycznych obciążeń dynamicznych jest znacznie niższa od wyznaczonej dla globalnej postaci wyboczenia. Liczne obrazy dynamicznych zachowań płyt przedstawione w postaci wykresów warstwicowych oraz wiele sformułowanych uwag i spostrzeżeń mogą mieć istotne znaczenie zarówno poznawcze, jak i praktyczne w dziedzinie dynamiki płyt kompozytowych.
Źródło:
Archive of Mechanical Engineering; 2015, LXII, 3; 315-332
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of geometric imperfections on the stability of three-layer beams with foam core
Autorzy:
Wstawska, I.
Powiązania:
https://bibliotekanauki.pl/articles/94106.pdf
Data publikacji:
2017
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
stability
buckling
three-layer beam
pure bending
FEM
stabilność
wyboczenia
belka trójwarstwowa
czyste zginanie
Opis:
The main objective of this work is the numerical analysis (FE analysis) of stability of three-layer beams with metal foam core (alumina foam core). The beams were subjected to pure bending. The analysis of the local buckling was performed. Furthermore, the influence of geometric parameters of the beam and material properties of the core (linear and non-linear model) on critical loads values and buckling shape were also investigated. The calculations were made on a family of beams with different mechanical properties of the core (elastic and elastic-plastic material). In addition, the influence of geometric imperfections on deflection and normal stress values of the core and the faces has been evaluated.
Źródło:
Archives of Mechanical Technology and Materials; 2017, 37; 65-69
2450-9469
Pojawia się w:
Archives of Mechanical Technology and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic stability of mechanically and thermally loaded three-layered annular plate with viscoelastic core
Autorzy:
Pawlus, Dorota
Powiązania:
https://bibliotekanauki.pl/articles/2146605.pdf
Data publikacji:
2020
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
dynamic stability
composite plate
thermo-mechanical loading
rheological material
stabilność dynamiczna
płyta kompozytowa
obciążenia termodynamiczne
materiał reologiczny
Opis:
The problem of dynamic stability of composite three-layered annular plate with viscoelastic core is the subject of the consideration. Plate composed of thin outer layers and soft core is loaded quickly in time with forces compressing facings and with temperature gradient in radial direction. Two kinds of plate support system are analysed: plate slideably clamped in thermo-mechanical problem and plate clamped on both edges in thermal analysis. The analytical and numerical solution, which is based on the orthogonalization and finite difference methods includes axisymmetric and asymmetric forms of buckling and rheological properties of plate core.
Źródło:
Vibrations in Physical Systems; 2020, 31, 2; art. no. 2020223
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of viscosity difference on the instability of the core-annular flow
Autorzy:
Rożeń, A.
Bałdyga, J.
Powiązania:
https://bibliotekanauki.pl/articles/1955730.pdf
Data publikacji:
2003
Wydawca:
Politechnika Gdańska
Tematy:
laminar flow
micromixing
stability analysis
viscous liquids
Opis:
The process of destabilisation of an axi-symmetric, core-annular flow (CAF) of two Newtonian fully miscible liquids widely differing in viscosity is investigated. Formation of periodic structures is observed in experiments, predicted by the linear stability theory and simulated numerically using the volume of fluid method (VOF). Possible influence of this phenomenon on mixing on the molecular scale is discussed.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2003, 7, 3; 425-438
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 20

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