Models of Hybrid Springs for Ergonomic Seats and Mattresses

Smardzewski, Jerzy

doi:10.5552/drind.2013.1230

Cited by 3 publications

(4 citation statements)

References 36 publications

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“…Hence, the auxetic material densifies under the impact in both the longitudinal and transverse directions, leading to increased indentation resistance. [44] Smardzewski [45][46] solved contact problem to find the values of acceptable stress in the contact between the human body and seats. It was defined the comfort threshold as the stress level at which the user can sit comfortably on the chair more than 4 h. It was emphasized that high user comfort in seats and mattresses was achieved by using materials with nonlinear stiffness characteristics creating little contact stress in the case of contact with a body.…”

Section: Introductionmentioning

confidence: 99%

Finite Element Analysis of the Influence of the Covering Auxetic Layer of Plate on the Contact Pressure

Stręk

Matuszewska

Jopek

2017

Physica Status Solidi (b)

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The contact problem between two bodies: plate and semi‐cylindrical bar is studied in this paper. The analysis concerns the contact pressure distribution along the contact region, as well as the deflection of the plate. Furthermore, the case of a composite plate covered with the auxetic layer is also considered. The influence of the Poisson's ratio of the layer on the behavior of the plate is studied. The contact pressure distribution along the contact area is analyzed using finite element analysis.

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Section: Introductionmentioning

confidence: 99%

Finite Element Analysis of the Influence of the Covering Auxetic Layer of Plate on the Contact Pressure

Stręk

Matuszewska

Jopek

2017

Physica Status Solidi (b)

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“…Although the hybrid spiral spring designed by Smardzewaki for ergonomic cushions and mattresses and the TPU airbag designed by Takashima are both capable of adjusting stiffness, the present air spring has the advantage of active stiffness compared to the former two. Moreover, the hybrid spiral spring consists of two springs of different lengths nested together, [8,9] so that the stiffness of the hybrid spring is equivalent to the stiffness of two springs in parallel. For small body weight populations, only the longer spring acts, where the stiffness is relatively low, while for large body weight populations, both the springs are compressed, generating relatively larger stiffness.…”

Section: Advantages and Application Value Of An Air Springmentioning

confidence: 99%

“…In 2013, Smardzewski designed for the first time a hybrid spiral spring nested with two springs being different in length and external diameter, meanwhile modeling a parametric stiffness prediction model. [ 8,9 ] In the same year, Smardzewski designed a structure similar to spring in function presenting three‐stage processes during compression, namely, linear elastic phase, plateau phase, and densification phase. [ 10 ] Then the characteristics of a cushion made of polyurethane foam and the new springs were investigated.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear Stiffness Characteristics and Model of Air Spring for Mattress based on Finite Element and Numerical Analysis

Yao

Shen

2022

Advcd Theory and Sims

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To investigate the nonlinear stiffness characteristics and the model of an air spring for mattresses on arbitrary working conditions, a finite element model of an air spring is established, modified by response surface method and verified by uniaxial compression experiment on conditions of different initial inner pressure. Then the static stiffness characteristics on arbitrary working conditions are analyzed by finite element analysis in ABAQUS. In addition, the model for engineering control is established and the stiffness characteristics are analyzed by numerical method under working conditions. The results demonstrate the nonlinear stiffness of an air spring is positively correlated with the inner pressure and compression displacement. Additionally, a finite element model is established with average relative error ratio of 0.059 and 0.074 on conditions of compression by 20 and 30 mm, respectively, satisfying engineering requirement. Moreover, the stiffness model of an air spring on any working conditions is established by fitting surfacecontaining compression displacement and inner pressure at equilibrium position then calculating its partial derivative with respect to compression displacement. The present study suggests the nonlinear stiffness prediction model of an air spring is applicable to any working conditions, only requiring inner pressure at initial and equilibrium conditions.

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“…Due to their bulky size, it is almost impossible to accurately predict and adjust their stiffness to a certain level to maintain natural spinal alignment, which is another limitation of air mattresses. Although the hybrid spiral steel spring used in ergonomic mattresses overcome the limitations of air chambers to some extent by providing predictable and variable stiffness [23,24], they also fail to accommodate personalized lying postures and body dimensions. On the basis of previous studies, a novel spring characterized by variable and predictable stiffness needs to be explored.…”

Section: Introductionmentioning

confidence: 99%

Mechanical characteristic and analytical model of novel air spring for ergonomic mattress

Yao

Shen

Liu

2021

Mechanics & Industry

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Conventional mattresses can not adjust precisely according to the individualized spinal alignment. In addition, there is no theoretical basis for quantitative design and adjustment of mattresses firmness. The purpose of this paper is to overcome deficiency of traditional air chambers for research of ergonomic mattresses in accordance with spinal alignment. A novel variable stiffness air spring was designed and static experiments were conducted to analyze its mechanical properties and its influence factors. An analytical model based on geometric parameters and initial internal pressure was established. The results showed that the air spring has nonlinear stiffness during the working process. Furthermore, the model can predict the load of the air spring accurately at any equilibrium position with an average error of 6.96%. The initial stiffness, volume and assembly height could be predicted by means of geometric parameters and initial internal pressure. The conclusions are that the novel air spring can obtain predictable stiffness compared with cubic and the rod-shaped air chambers, which provides a theoretical basis and possible solution for the study of stiffness adaptive ergonomic mattress according to spinal alignment.

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Models of Hybrid Springs for Ergonomic Seats and Mattresses

Abstract: • An ergonomic seat or mattress has to provide optimal and uniform support for the body of a man or a woman with similar or slightly differing size centiles. It is a common opinion that

Cited by 3 publications

References 36 publications

Finite Element Analysis of the Influence of the Covering Auxetic Layer of Plate on the Contact Pressure

Finite Element Analysis of the Influence of the Covering Auxetic Layer of Plate on the Contact Pressure

Nonlinear Stiffness Characteristics and Model of Air Spring for Mattress based on Finite Element and Numerical Analysis

Mechanical characteristic and analytical model of novel air spring for ergonomic mattress

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