Characterization of human passive muscles for impact loads using genetic algorithm and inverse finite element methods

Abstract

The objective of this study is to identify the dynamic material properties of human passive muscle tissues for the strain rates relevant to automobile crashes. A novel methodology involving genetic algorithm (GA) and finite element method is implemented to estimate the material parameters by inverse mapping the impact test data. Isolated unconfined impact tests for average strain rates ranging from 136 s(-1) to 262 s(-1) are performed on muscle tissues. Passive muscle tissues are modelled as isotropic, linear and viscoelastic material using three-element Zener model available in PAMCRASH(TM) explicit finite element software. In the GA based identification process, fitness values are calculated by comparing the estimated finite element forces with the measured experimental forces. Linear viscoelastic material parameters (bulk modulus, short term shear modulus and long term shear modulus) are thus identified at strain rates 136 s(-1), 183 s(-1) and 262 s(-1) for modelling muscles. Extracted optimal parameters from this study are comparable with reported parameters in literature. Bulk modulus and short term shear modulus are found to be more influential in predicting the stress-strain response than long term shear modulus for the considered strain rates. Variations within the set of parameters identified at different strain rates indicate the need for new or improved material model, which is capable of capturing the strain rate dependency of passive muscle response with single set of material parameters for wide range of strain rates.

Application of Optimization Methodology and Specimen-Specific Finite Element Models for Investigating Material Properties of Rat Skull

“…Additionally, no literature has been published to date reporting rat skull properties at different loading rates. Finally, although optimization methods have been used in biomaterial identification problems, 4,14,32,33 little information was provided regarding which optimization procedures were applied.…”

Development of novel synthetic muscle tissues for sports impact surrogates

“…This was a trend across all silicones (Silastic 3481 and PDMS) and is likely to indicate an innate difference in the mechanical behaviour with organic tissues, rather than issues with the quality of the formulations. However, although the primary target dataset is based on porcine and bovine sources, at low strain and high strain rates the formulated PDMS relaxed muscle simulant is convieniently a close match to Chawla (2009) and Balaraman et al (2012) human tissue response data (Fig. 15).…”

“…There is also a paucity of good quality research in human tissue properties due to difficulties in obtaining post-mortem human subjects and the degradation in properties associated with the conditions the body is kept post-mortem prior to testing (Van Ee et al, 2000) and storage conditions (Menz, 1971;Lee & Pelker, 1985;Clavert et al, 2001). Consequently, very few studies presented are of human tissues (Chawla et al, 2009;Balaraman et al, 2012). Much more of the muscle characterisation research published being obtained from testing on more accessible organic animal specimens such as bovine (McElhaney, 1966;Van Sligtenhorst et al, 2006) or porcine sources (Song et al, 2007;Van Loocke et al, 2006, 2009.…”

“…McElhaney (1966) conducted a seminal study characterising in vitro bovine tissues around the femur in uniaxial compression using both a Tinius-Olsen electromatic test machine and an air operated test machine for tests at low and high strain rates respectively. In recent years, authors have typically investigated the high strain rate response of soft tissues using a polymeric Split Hopkinson Pressure Bar (SHPB), capable of testing in the order of 10 3 s -1 (Van Sligtenhorst et al, 2006;Song et al, 2007;Chawla et al, 2009;Balaraman et al, 2012). There is, however, a paucity of information conducted under intermediate strain rate conditions in a similar range to those expected in sports impact scenarios (approximately 50-500s -1 ), based on a maximal velocity projectile impact from a cricket ball of 34.6ms -1 (Penrose et al, 1976).…”

Incidence of the boundary condition between bone and soft tissue in a finite element model of a transfemoral amputee

“…The use of the FE method to simulate the human body parts, processes and its interactions with the environment has been increasing; however, usually specific models have to be developed. [1][2][3] This specificity makes these models incompatible between them or impossible to use one of them to simulate different conditions. 4 This situation obliges the new developers to start their own models from zero instead of building over pre-existent ones.…”