Purpose

This study aimed to develop a method to calculate the mattress indentation for further estimating spinal alignment.

Design/methodology/approach

A universal indentation calculation model is derived based on the system theory, and the deformation characteristics of each component are analyzed by the finite element (FE) model of a partial air-spring mattress under the initial air pressure of 0.01–0.025 MPa. Finally, the calculation error of the model is verified.

Findings

The results indicate that the indentation calculation model could describe the stain of a mattress given the load and the constitutive model of each element. In addition, the FE model of a partial air-spring mattress can be used for further simulation analysis with an error of 1.47–3.42 mm. Furthermore, the deformation of the series system is mainly contributed by the air spring and the components directly in contact with it, while the top component is mainly deflection deformation. In addition, the error of the calculation model is 2.17–5.59 mm on the condition of 0.01–0.025 MPa, satisfying the engineering application. Finally, the supine spinal alignment is successfully extracted from the mattress indentation.

Research limitations/implications

The limitation of this study is that it needs to verify the practicality of the indentation calculation model for the Bonnier spiral spring mattress. The main feature of the Bonnier spring mattress is that all springs are connected, so the mattress deflection and neighborhood effect are more significant than those of the air-spring mattress. Therefore, the applicability of the model needs to be tested. Moreover, it is worth further research to reduce the deformation error of each component.

Practical implications

As part of the series of studies on the intelligent air-spring mattress, the indentation-based evaluation method of spinal alignment in sleep postures will be studied for hardness and intelligent regulation based on this study.

Social implications

The results of this research are ultimately used for the intelligent adjustment of air-spring mattresses, which automatically adjusts the hardness according to the user's sleep postures and spinal alignment, thus maintaining optimal spinal biomechanics. The successful application of this result could improve the sleep health of the general public.

Originality/value

Based on the series system theory, an indentation calculation model for mattresses with arbitrary structure is proposed, overcoming the dependence of parameters on materials and their combinations when fitting the Burgers model. Further, the spinal alignment in supine posture is extracted from the indentation, laying a theoretical foundation for further recognition and adjustment of the spinal alignment of the intelligent mattress.

中文翻译：

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新型空气弹簧床垫压痕计算的方法和有限元验证：用于估计睡眠姿势中的脊柱对齐

目的

本研究旨在开发一种计算床垫压痕的方法，以进一步估计脊柱排列。

设计/方法论/途径

基于系统论推导了通用压痕计算模型，并通过部分空气弹簧床垫在0.01~0.025 MPa初始气压下的有限元模型分析了各部件的变形特性。最后验证了模型的计算误差。

发现

结果表明，在给定载荷和各单元本构模型的情况下，压痕计算模型可以描述床垫的污渍。此外，部分空气弹簧床垫的有限元模型可用于进一步的仿真分析，误差为1.47~3.42 mm。此外，串联系统的变形主要由空气弹簧及其直接接触的部件贡献，而顶部部件主要是偏转变形。另外，在0.01~0.025 MPa条件下，计算模型误差为2.17~5.59 mm，满足工程应用。最后，成功地从床垫压痕中提取出仰卧脊柱排列。

研究局限性/影响

本研究的局限性在于需要验证Bonnier螺旋弹簧床垫压痕计算模型的实用性。邦尼尔弹簧床垫的主要特点是所有弹簧都是相连的，因此床垫的挠度和邻域效应比空气弹簧床垫更显着。因此，需要检验模型的适用性。此外，降低各部件的变形误差值得进一步研究。

实际影响

作为智能空气弹簧床垫系列研究的一部分，基于压痕的睡眠姿势脊柱排列评估方法将在此研究的基础上进行硬度和智能调节的研究。

社会影响

这项研究成果最终用于空气弹簧床垫的智能调节，根据用户的睡眠姿势和脊柱排列自动调节硬度，从而保持最佳的脊柱生物力学。这一成果的成功应用可以改善广大公众的睡眠健康。

原创性/价值

基于级数系统理论，提出了任意结构床垫压痕计算模型，克服了Burgers模型拟合时参数对材料及其组合的依赖。进一步，从压痕中提取出仰卧位的脊柱排列，为智能床垫脊柱排列的进一步识别和调整奠定了理论基础。