Mechanical Impedance of the Human Body in the Horizontal Direction

Holmlund, P.; Lundström, Ronnie

doi:10.1006/jsvi.1998.1593

Cited by 50 publications

(40 citation statements)

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“…Fairley and Griffin 8) reported one mode at about 0.7 Hz and another in the region of 1.5 to 3 Hz. Investigating frequencies greater than 1 Hz, Holmlund and Lundström 9) observed a single mode between 2 and 5 Hz while Mansfield and Lundström 10) reported modes around 3 Hz and 5 Hz. Nawayseh and Griffin 11) found three modes at frequencies less than 5 Hz (around 1 Hz, between 1 and 3 Hz, and between 3 and 5 Hz).…”

Section: Fore-and-aft In-line Apparent Mass Single-axis Excitationmentioning

confidence: 99%

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Biodynamic Responses of the Seated Human Body to Single-axis and Dual-axis Vibration

Qiu

Griffin

2010

Ind Health

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Occupational exposures to vibration always involve multi-axis vibration. Since human responses to vibration are highly nonlinear and cross-coupled, it is to be expected that excitation in one axis will alter response to vibration in another axis. The purpose of this study was to investigate nonlinearity in the apparent masses of subjects seated without a backrest and exposed to single-axis and dual-axis vertical and fore-and-aft excitation. The driving point apparent masses and cross-axis apparent masses in the two translational directions were measured with twelve subjects exposed to random vibration (0.2 to 20 Hz) in all 15 possible combinations of four vibration magnitudes (0, 0.25, 0.5, or 1.0 ms -2 r.m.s.) in the fore-and-aft and vertical directions. With single-axis excitation (either fore-and-aft or vertical), the median in-line apparent mass exhibited a nonlinear characteristic in which the body softened with increasing magnitude of vibration. With dual-axis excitation, at all magnitudes of vertical excitation the resonance frequency in the vertical apparent mass reduced as the magnitude of fore-and-aft vibration increased, and at all except the greatest magnitude of fore-andaft excitation the resonance frequency in the fore-and-aft apparent mass reduced as the magnitude of vertical vibration increased. The coherency between the fore-and-aft acceleration and the fore-and-aft force was lowered by the addition of vertical excitation, and the coherency between the vertical acceleration and the vertical force was lowered by the addition of fore-and-aft excitation. The nonlinearity evident in both in-line apparent masses was also evident in the crossaxis apparent masses. It is concluded that with dual-axis excitation the fore-and-aft and vertical response of the seated human body is nonlinear, with resonance frequencies decreasing with increasing magnitude of vibration. Consequently, vibration in one axis (either fore-and-aft or vertical) affects the apparent mass of the body measured in the other axis (either vertical or fore-and-aft).

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Section: Fore-and-aft In-line Apparent Mass Single-axis Excitationmentioning

confidence: 99%

“…Nonlinear biodynamic responses are not confined to vertical excitation but are also apparent during fore-and-aft and lateral excitation e.g., [8][9][10][11] .…”

Section: Introductionmentioning

confidence: 99%

Biodynamic Responses of the Seated Human Body to Single-axis and Dual-axis Vibration

Qiu

Griffin

2010

Ind Health

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“…Most biomechanical research to determine the full body vibration was focused on the vertical vibration of seated people [46]. In fewer researches they participated humans standing [47][48][49][50][51][52][53] or observed horizontal vibrations [46,[54][55][56][57]. When the results of biomechanical research of dynamic models of the complete human body are used in civil engineering, several important issues need to be considered.…”

Section: Dynamic Models In Civil Engineeringmentioning

confidence: 99%

Structural health monitoring of grandstands: a review

Fuentes

Castro-Triguero

García‐Macías

et al. 2015

MATEC Web of Conferences

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Abstract. This article is a state of the art about Grandstands. The Grandstands are slender structures designed to accommodate a large number of people, which are specially under the actions of wind and the human-structure interaction. Over the years, it has been discuss of this topic, although still the number of publications still remain low. The human-structure interaction is a complex issue, where the loads may have different behaviours, depending many factors, including: type of audience (active or passive), public behaviour (jumping, walking, running, clapping, vandal loads), type of event (sports, concerts, meeting), position and posture of the individual, even influences the type of seat (with or without back, stiffness). However, the structure will behave differently when empty or fully occupied. Another load to consider is the wind, especially when the structure has a roof, screens, large-scale advertising, etc. These two types of loads can interact together, which implies an increase in the normal number of load combinations to consider. There are biomechanical models of human behaviour, used for design these types of structures. In addition, there are mathematical models to simulate the behaviour of the Grandstands by numerical methods. In recent years, all these models are throwing good results, against laboratory tests performed. It has also been monitored real Grandstands. This paper compiles all existing information on this topic.

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“…For whole-body vibration, important contributions have been made by many, including: Fairley 21,22) , Holmlund 18,[23][24][25][26] , Mansfield 16,19,[27][28][29][30][31][32] , Matsumoto 33,34) , Miwa 35) , Nawayseh 36,37) , Rakheja [38][39][40][41][42] , and Smith 43,44) . Although contributions have been made by many individuals, example data presented here will be sourced primarily from the author's own work due to availability of raw data and knowledge of all experimental conditions.…”

Section: Example Impedance Data From the Literaturementioning

confidence: 99%

Impedance Methods (Apparent Mass, Driving Point Mechanical Impedance and Absorbed Power) for Assessment of the Biomechanical Response of the Seated Person to Whole-body Vibration

Mansfield

2005

Ind Health

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Exposure to whole-body vibration is a risk factor for the development of low back pain. In order to develop a fuller understanding of the response of the seated person to vibration, experiments have been conducted in the laboratory investigating the biomechanics of the seated person. Some of these methods are based on the driving force and acceleration at the seat and are reported in the literature as apparent mass, driving point mechanical impedance or absorbed power. This paper introduces the background behind such impedance methods, the theory and application of the methods. It presents example data showing typical responses of the seated human to wholebody vibration in the vertical, fore-and-aft and lateral directions. It also highlights problems that researchers might encounter in performing, analysing and interpreting human impedance data.

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Mechanical Impedance of the Human Body in the Horizontal Direction

Cited by 50 publications

References 0 publications

Biodynamic Responses of the Seated Human Body to Single-axis and Dual-axis Vibration

Biodynamic Responses of the Seated Human Body to Single-axis and Dual-axis Vibration

Structural health monitoring of grandstands: a review

Impedance Methods (Apparent Mass, Driving Point Mechanical Impedance and Absorbed Power) for Assessment of the Biomechanical Response of the Seated Person to Whole-body Vibration

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