Biomechanical model for simulating impacts against protective padding of sport facility

2015 ◽  
Vol 19 (1) ◽  
pp. 47-57 ◽  
Author(s):  
Pier Paolo Valentini ◽  
Ettore Pennestrì ◽  
Leonardo Quattrociocchi
Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 601 ◽  
Author(s):  
Marco Germanotta ◽  
Ilaria Mileti ◽  
Ilaria Conforti ◽  
Zaccaria Del Prete ◽  
Irene Aprile ◽  
...  

The estimation of the body’s center of mass (CoM) trajectory is typically obtained using force platforms, or optoelectronic systems (OS), bounding the assessment inside a laboratory setting. The use of magneto-inertial measurement units (MIMUs) allows for more ecological evaluations, and previous studies proposed methods based on either a single sensor or a sensors’ network. In this study, we compared the accuracy of two methods based on MIMUs. Body CoM was estimated during six postural tasks performed by 15 healthy subjects, using data collected by a single sensor on the pelvis (Strapdown Integration Method, SDI), and seven sensors on the pelvis and lower limbs (Biomechanical Model, BM). The accuracy of the two methods was compared in terms of RMSE and estimation of posturographic parameters, using an OS as reference. The RMSE of the SDI was lower in tasks with little or no oscillations, while the BM outperformed in tasks with greater CoM displacement. Moreover, higher correlation coefficients were obtained between the posturographic parameters obtained with the BM and the OS. Our findings showed that the estimation of CoM displacement based on MIMU was reasonably accurate, and the use of the inertial sensors network methods should be preferred to estimate the kinematic parameters.


1998 ◽  
Vol 1 (1) ◽  
pp. 23-39
Author(s):  
Carter J. Kerk ◽  
Don B. Chaffin ◽  
W. Monroe Keyserling

The stability constraints of a two-dimensional static human force exertion capability model (2DHFEC) were evaluated with subjects of varying anthropometry and strength capabilities performing manual exertions. The biomechanical model comprehensively estimated human force exertion capability under sagittally symmetric static conditions using constraints from three classes: stability, joint muscle strength, and coefficient of friction. Experimental results showed the concept of stability must be considered with joint muscle strength capability and coefficient of friction in predicting hand force exertion capability. Information was gained concerning foot modeling parameters as they affect whole-body stability. Findings indicated that stability limits should be placed approximately 37 % the ankle joint center to the posterior-most point of the foot and 130 % the distance from the ankle joint center to the maximal medial protuberance (the ball of the foot). 2DHFEC provided improvements over existing models, especially where horizontal push/pull forces create balance concerns.


2005 ◽  
Vol 4 (4) ◽  
pp. 281-290
Author(s):  
Silvia Taloni ◽  
Giovanni Carlo Cassavia ◽  
Giuseppe Luca Ciavarro ◽  
Giuseppe Andreoni ◽  
Giorgio Cesare Santambrogio ◽  
...  

Back pain is one of the most significant socioeconomic problem in industrialized countries. Its origin is multifactorial, including physical, psychosocial and individual risk factors. Among the working population, nursery teachers are highly exposed to back pain diseases, but not many studies have dealt with this problem. So a suitable quantitative index is proposed, based on an unobtrusive video-analysis of established motor-tasks. In particular five nursery teachers were asked to perform lifting and lowering movements placing their feet at two different distances from a weight (a toy pet loaded with 8 kg, simulating a child) with different strategies (flexed, partially flexed and extended legs). The index is based on the idea that a greater trunk inclination angle determines increased loads on the lumbar spine, and so an augmented probability of spinal disorders. To validate our protocol, the same data were analyzed through a 3D biomechanical model (gold standard method), which computes the loads on L3-L4 intervertebral disc. Data show a good correspondence between the risk level suggested by the index and the one indicated by the mechanical loads: the antero-posterior shearing forces and the values of index coherently increase with the reduction of leg flexion.


2021 ◽  
Vol 82 (5) ◽  
Author(s):  
Hannah J. Pybus ◽  
Amanda L. Tatler ◽  
Lowell T. Edgar ◽  
Reuben D. O’Dea ◽  
Bindi S. Brook

AbstractPrecision-cut lung-slices (PCLS), in which viable airways embedded within lung parenchyma are stretched or induced to contract, are a widely used ex vivo assay to investigate bronchoconstriction and, more recently, mechanical activation of pro-remodelling cytokines in asthmatic airways. We develop a nonlinear fibre-reinforced biomechanical model accounting for smooth muscle contraction and extracellular matrix strain-stiffening. Through numerical simulation, we describe the stresses and contractile responses of an airway within a PCLS of finite thickness, exposing the importance of smooth muscle contraction on the local stress state within the airway. We then consider two simplifying limits of the model (a membrane representation and an asymptotic reduction in the thin-PCLS-limit), that permit analytical progress. Comparison against numerical solution of the full problem shows that the asymptotic reduction successfully captures the key elements of the full model behaviour. The more tractable reduced model that we develop is suitable to be employed in investigations to elucidate the time-dependent feedback mechanisms linking airway mechanics and cytokine activation in asthma.


2021 ◽  
Vol 2 ◽  
Author(s):  
Erik P. Lamers ◽  
Karl E. Zelik

Abstract Occupational exoskeletons and exosuits have been shown to reduce muscle demands and fatigue for physical tasks relevant to a variety of industries (e.g., logistics, construction, manufacturing, military, healthcare). However, adoption of these devices into the workforce has been slowed by practical factors related to comfort, form-factor, weight, and not interfering with movement or posture. We previously introduced a low-profile, dual-mode exosuit comprised of textile and elastic materials to address these adoption barriers. Here we build upon this prior work by introducing an extension mechanism that increases the moment arm of the exosuit while in engaged mode, then collapses in disengaged mode to retain key benefits related to being lightweight, low-profile, and unobstructive. Here we demonstrate both analytically and empirically how this extensible exosuit concept can (a) reduce device-to-body forces (which can improve comfort for some users and situations), or (b) increase the magnitude of torque assistance about the low back (which may be valuable for heavy-lifting jobs) without increasing shoulder or leg forces relative to the prior form-fitting exosuit. We also introduce a novel mode-switching mechanism, as well as a human-exosuit biomechanical model to elucidate how individual design parameters affect exosuit assistance torque and device-to-body forces. The proof-of-concept prototype, case study, and modeling work provide a foundation for understanding and implementing extensible exosuits for a broad range of applications. We envision promising opportunities to apply this new dual-mode extensible exosuit concept to assist heavy-lifting, to further enhance user comfort, and to address the unique needs of last-mile and other delivery workers.


Author(s):  
Nenad Filipovic ◽  
Zarko Milosevic ◽  
Igor Saveljic ◽  
Dalibor Nikolic ◽  
Nebojsa Zdravkovic ◽  
...  
Keyword(s):  

Author(s):  
A Tabatabaie Arani ◽  
Ali Ghorbanpour Arani ◽  
Reza Kolahchi

The high blood rate that often occurs in carotid arteries may play a role in artery failure and tortuosity which leads to blackouts, transitory ischemic attacks, and other diseases. However, dynamic analysis of carotid arteries conveying blood is lacking. The objective of this study was to present a biomechanical model for dynamic instability analysis of the embedded carotid arteries conveying pulsating blood flow. In order to present a realistic model, the carotid arteries and tissues are assumed viscoelastic using Kelvin–Voigt model. Carotid arteries are modeled as elastic cylindrical vessels based on Mindlin cylindrical shell theory (MCST). One of the main advantages of this study is considering the pulsating non-Newtonian nature of the blood flow using Carreau, Casson, and power law models. Applying energy method, Hamilton’s principle and differential cubature method (DCM), the dynamic instability region (DIR) of the visco-carotid arteries is obtained. The detailed parametric study is conducted, focusing on the combined effects of the elastic medium and non-Newtonian models on the dynamic instability of the visco-carotid arteries. It can be seen that with increasing the tissue stiffness, the natural frequency of visco-carotid arteries decreases. The current model provides a powerful tool for further experimental investigation about arterial tortuosity.


Ergonomics ◽  
1994 ◽  
Vol 37 (9) ◽  
pp. 1495-1502 ◽  
Author(s):  
M. P. DE LOOZE ◽  
I. KINGMA ◽  
W. THUNNISSEN ◽  
M. J. VAN WIJK ◽  
H. M. TOUSSAINT

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3297
Author(s):  
Philipp M. Schmid ◽  
Christoph M. Bauer ◽  
Markus J. Ernst ◽  
Bettina Sommer ◽  
Lars Lünenburger ◽  
...  

Neck pain is a frequent health complaint. Prolonged protracted malpositions of the head are associated with neck pain and headaches and could be prevented using biofeedback systems. A practical biofeedback system to detect malpositions should be realized with a simple measurement setup. To achieve this, a simple biomechanical model representing head orientation and translation relative to the thorax is introduced. To identify the parameters of this model, anthropometric data were acquired from eight healthy volunteers. In this work we determine (i) the accuracy of the proposed model when the neck length is known, (ii) the dependency of the neck length on the body height, and (iii) the impact of a wrong neck length on the models accuracy. The resulting model is able to describe the motion of the head with a maximum uncertainty of 5 mm only. To achieve this high accuracy the effective neck length must be known a priory. If however, this parameter is assumed to be a linear function of the palpable neck length, the measurement error increases. Still, the resulting accuracy can be sufficient to identify and monitor a protracted malposition of the head relative to the thorax.


Sign in / Sign up

Export Citation Format

Share Document