Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: step frequency

Sortuj według:

Ogranicz wyniki do:

Development of dynamic load factors for human walking excitation for floor vibration design

Nguyen Huu Anh Tuan, Lythgo Noel, Gad Emad, Wilson John, Haritos Nicholas

International Journal of Applied Mechanics and Engineering

2022

Vol. 27, no. 3

103--114

This paper discusses the derivation of a set of dynamic load factors for calculation of walking response on the basis of measurements made during a biomechanics research carried out with young adults. Firstly, a quite large number of experimental data on single footstep force were collected. The single footstep forces were then superimposed to generate the force time history for a continuous walk. This was followed by the transformation of the resultant force to the frequency domain from which the dynamic load factors for the first ten harmonics of a pacing rate can be extracted. A statistical analysis was employed on the dynamic load factors to acquire their design values in terms of the 90-th or 95-th percentile. The waking force function recommended by various design guides and that developed in the paper were then used in a comprehensive finite element model to predict the vibration level of a building floor. Current design guides on floor vibration normally suggest using four harmonics in the walking force whereas load factors for ten harmonics were developed in this paper. The acceleration response of the floor was found to increase by 5-33% when walking harmonics beyond the fourth harmonic were considered. The inclusion of higher harmonics would therefore lead to a more conservative estimation of the floor response.

The impact of changes in gait speed and step frequency on the extent of the center of mass displacements

Staszkiewicz R., Ruchlewicz T., Forczek W., Laska J.

Acta of Bioengineering and Biomechanics

2010

Vol. 12, no. 3

13-20

Center of mass (COM) trajectory plays a crucial role in the analysis of human body movements. This research aimed at studying vertical and transverse COM displacements during gait on a treadmill at a given velocity and step frequency. Locomotion study was accomplished using: Vicon 250, Cardionics Treadmill 3113 and metronome Korg Ma-30. The data achieved for 12 women and 15 men aged 21–22 revealed similarity in vertical COM oscillations in both groups. Lateral COM displacements (LCOM) were slightly higher in men than in women and they showed tendency to decrease as gait velocity increased. During natural locomotion there was an increasing trend as walking speed increased. At a given velocity of locomotion LCOM were decreasing as step frequency increased. The only astonishing thing was that the biggest changes of vertical COM oscillations (VCOM) were noticed at the fastest walking speed (6 km/h). It seems that so large decrease in VCOM during walking with high velocity and increased step cadency is a consequence of considerable shortening of the movement cycles and performing time of one step.