Mechanical Properties of Polyurethane-Foam Impact Limiters

Strain Measures for Rigid Crushable Foam in Uniaxial Compression

“…The first is continuum modelling. A number of theories have been presented, namely critical state theory, which is used in standard finite element codes such as ABAQUS, and enhancements have been developed to take account of specific foam behaviour [9][10][11][12][13][14][15][16][17]. The second approach is micro-modelling, in which the actual cellular structure is modelled [18].…”

Experimental and simulated high strain dynamic loading of polyurethane foam

“…Thus, to compute the a parameter, it is necessary to measure the initial uniaxial compressive yield strength (s 0 uc ), the yield stress in hydrostatic tension (s ht ) and initial hydrostatic compressive yield strength (s 0 hc ). Numerical values obtained from [3,16,17] are provided in Table 3.…”

“…Polymer foam stress-strain response has been extensively researched in uniaxial compression loading and to a lesser extent, hydrostatic compression loading, at quasistatic strain rates [2,3]. The uniaxial compressive stressstrain response at this rate (dynamic stress-strain response similar) is divided into three distinct regions: elastic, (relatively) constant stress, and densification (see Fig.…”

“…This material behavior has been attributed to collapsing "bands" within the cellular structure resulting in a progressive collapse of the foam material [7e9]. Once the cells have fully collapsed, the foam reaches a "locking strain", whereby small increases in strain result in very large increases in stress that is more reminiscent of the foam's original solid material behavior [3,10]. In energy absorption applications, this particular loading profile means that stresses much greater than the collapsing stress cannot be transmitted by the foam until the locking strain is reached [4].…”

A Practical Procedure for Measuring the Stiffness of Foam like Materials

“…In the literature, a number of studies have evaluated the mechanical properties of polyurethane (PU) foams [1][2][3][4], primarily in the context of an alternative to trabecular bone, considering compressive [5][6][7][8], shear [9] and fatigue [10] properties. However, results have varied markedly as the uniaxial compression test is subject to a number of experimental artefacts that degrade measurement accuracy:…”