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

Abstract

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.

A dual fusion recognition model for sleep posture based on air mattress pressure detection

“…The sleep posture recognition model for air beds proposed in 13 still uses image data as input, which is computationally intensive and not very portable. In contrast, the design of air springs 14 , as well as the design of the air bed structure 15 makes the integration of sleep posture recognition and mattress adaptive adjustment system possible. Currently, the mainstream detection methods for invasive 16 and non-invasive 17 sleep posture recognition are categorized into three main types: wearable device-based detection methods, vision-based detection methods, and pressure detection-based methods.…”

Method and finite element verification of indentation calculation for a novel air-spring mattress: for estimating spinal alignment in sleep postures

“…A novel air-spring mattress prototype was designed and manufactured using the novel air spring (Chao and Shen, 2022) to adjust hardness automatically according to the spinal alignment, consisting of the mattress with bedding layers, air springs and the embedded control system. Figure 1 illustrates the structure of the air-spring mattress, where the trunk area was an 11-order matrix containing 121 air springs divided into four areas in different colors, which were adjusted by four control systems efficiently, which was controlled by a central control system.…”

“…The base plate was defined as an analytical rigid body. It should be noted that the air-spring FE model here had been described in detail in a previously published work (Chao and Shen, 2022). In the air-spring FE model, 1,508 quadrilateral elements S4R and 52 triangular elements S3 were generated with the global mesh size of 10 mm by linear reduced integral and linear complete integral, respectively.…”

“…In the last published work on air-spring FE model (Chao and Shen, 2022), the sensitivity analysis of the FE model of air spring was specially carried out, and the results indicated that the constitutive model parameters of the Thermoplastic polyurethane (TPU) fabric composite significantly affected the simulation accuracy. Finally, the model error was reduced to less than 10% after modified by the response surface method (RSM).…”

Development of Static Test Equipment and a System for Lever-Loaded Air Springs

“…However, it is worth noting that due to the state of development of relevant production technologies in the automobile industry, especially the shortcomings of rubber synthetic materials related to air springs, the mass production of domestic air springs is still in its infancy [2]. A large number of researchers have performed the mathematical modeling of air springs using computer numerical analysis software [3,4] and have analyzed the inherent characteristics of air springs with the help of finite element simulation software [5,6]. However, the performance of air springs is affected by multiple factors, such as the synthetic materials used, the production processes and the production batches [7].…”