Identification of Nonlinear and Viscoelastic Properties of Flexible Polyurethane Foam

Singh, Rajendra; Davies, Patricia; Bajaj, Anil K.

doi:10.1023/b:nody.0000013511.07097.87

Cited by 48 publications

(57 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…If the uncompressed height of the foam block is H and the deformed height is x, the strain ε is defined as ε = H-x H . This formulation for the constitutive model of foam is based on the model structure introduced by White et al 26) , Singh et al 27,28) and Ippili et al 23) and was used by Puri 24) for the prediction of the static equilibrium of a seated occupant.…”

Section: Constitutive Foam Modelmentioning

confidence: 99%

“…The first three harmonic components of the response are shown for the 0.1g and 0.2 g cases, as the higher harmonic components are negligible. The damping constant used to obtain the frequency response is based on previous studies 27) where experimental data for steady-state forced response of the foam-block system to base excitation was used to estimate system model parameters around various compression levels. It is seen from Fig.…”

Section: Single-degree-of-freedom Foam-block Systemmentioning

confidence: 99%

See 1 more Smart Citation

Whole-body Vibratory Response Study Using a Nonlinear Multi-body Model of Seat-occupant System with Viscoelastic Flexible Polyurethane Foam

2010

View full text Add to dashboard Cite

Vehicle occupants are exposed to low frequency vibrations with possible harmful effects such as mild discomfort, lower back pain, and even injury to the spine. Occupational drivers and operators of heavy machinery are exposed to significantly longer duration and higher levels of vibration. Thus, the modeling and prediction of biodynamic response of seated occupants to such vibrations is very important. Since the properties of seating foam affect the response of the occupant, there is need for good models of seat-occupant systems through which the effects of foam properties on the dynamic response can be directly evaluated. A nonlinear planar seat-occupant model which incorporates the nonlinear viscoelastic behavior of seating foam has been developed. This model is used to study response of the occupant to harmonic excitation applied at the seat base, in terms of the frequency response in vertical and fore-and-aft directions, the deflection shapes at resonance, as well as the seat-to-head-transmissibility. In addition, to better understand the role of flexible polyurethane foam in characterizing the system behavior, the response of a single-degree-of-freedom foam-block system is also studied. The effects of different masses riding on the foam block and undergoing vertical vibrations at different acceleration levels are also investigated.

show abstract

Section: Constitutive Foam Modelmentioning

confidence: 99%

Section: Single-degree-of-freedom Foam-block Systemmentioning

confidence: 99%

Whole-body Vibratory Response Study Using a Nonlinear Multi-body Model of Seat-occupant System with Viscoelastic Flexible Polyurethane Foam

2010

View full text Add to dashboard Cite

show abstract

“…A number of studies have considered foam behaviour in different test conditions. In mechanics, there are four types of studies: static behaviour [3,4] , quasi-static behaviour [5][6][7][8][9], dynamic behaviour [9][10][11][12][13][14] and fatigue behaviour [15,16]. All these studies show that foam cannot be considered as a purely elastic material or as a purely viscous material.…”

Section: Symbolsmentioning

confidence: 99%

“…These energetic models confirm the nonlinear elastic behaviour of foam undergoing large deformation. As regards specific foam macroscopic memory models, there are two types of models: the integer memory model [9,[11][12][13] and the fractional memory model [5,10]. They illustrate the historical effect on the behaviour of foam.…”

Section: Symbolsmentioning

confidence: 99%

Quasi-static behavior identification of polyurethane foam using a memory integer model and the difference-forces method

Jmal

Dupuis

Aubry

2011

Journal of Cellular Plastics

View full text Add to dashboard Cite

. Quasi-static behavior identification of polyurethane foam using a memory integer model and the difference-forces method. Journal of Cellular Plastics, SAGE Publications, 2011, pp.447-465 ABSTRACT: Flexible polyurethane (PU) foam is widely used in numerous comfort applications such as automotive seat cushions and mattresses. It would be interesting to design a mechanical model which describes the behaviour of this material in a series of test conditions. The present study is devoted to the modelling of the quasi-static behaviour of polyurethane foam using a memory integer model. Polyurethane foam undergoing large compressive deformation exhibits highly nonlinear elasticity and a viscoelastic behaviour. The memory integer model describes the nonlinearity in a polynomial function and the viscoelasticity through a convolution function. Uni-axial compression tests help to identify the mechanical parameters of the model. The difference between the force responses of foam in load and unload phases constitute the base element of the method used in this paper. Numerous precautions are taken into account to obtain accurate results which verify the thermodynamic conditions. Finally, the reliability as well as the limits of the memory integer model are discussed.

show abstract

“…A material is called memory viscoelastic if the present state of response depends, not only on the present state of loading, but also on the previous states [31,32]. Polyurethane foams exhibit a significant hysteretic response during unloading after prior loading in uniaxial compression.…”

Section: Introductionmentioning

confidence: 99%

Visco-hyperelastic constitutive model for modeling the quasi-static behavior of polyurethane foam in large deformation

Jmal

Dupuis

et al. 2014

Polym Eng Sci

View full text Add to dashboard Cite

Flexible polyurethane foam is widely used in numerous applications such as seats and mattresses, due to its low stiffness and its ability to absorb deformation energy. The main objective of this article is to model the quasi-static mechanical behavior of three types of polyurethane foam in large deformation and to compare these three foams with three proposed models. The uniaxial compression/ decompression tests at three different strain rates were performed. The test results show that the three foams present different plateau stresses, maximum stresses, and abilities to absorb energy. Moreover, polyurethane foam also presents a nonlinear hyperelastic behavior and a viscoelastic behavior in large deformation. Three viscohyperelastic models which include a hyperelastic component and a memory component are proposed to model these behaviors. Model parameters were identified using the experimental data and a proper identification method. These models were validated on these three types of foam with the aim to present comparison results. The comparison results show that Ogden's viscoelastic model best agrees with the experimental results. POLYM. ENG. SCI., 55:1795SCI., 55: -1804SCI., 55: , 2015

show abstract

Identification of Nonlinear and Viscoelastic Properties of Flexible Polyurethane Foam

Cited by 48 publications

References 20 publications

Whole-body Vibratory Response Study Using a Nonlinear Multi-body Model of Seat-occupant System with Viscoelastic Flexible Polyurethane Foam

Whole-body Vibratory Response Study Using a Nonlinear Multi-body Model of Seat-occupant System with Viscoelastic Flexible Polyurethane Foam

Quasi-static behavior identification of polyurethane foam using a memory integer model and the difference-forces method

Visco-hyperelastic constitutive model for modeling the quasi-static behavior of polyurethane foam in large deformation

Contact Info

Product

Resources

About