Modeling Bioactive Materials

Abstract

In this chapter we examine the mechanical properties of the ventral interior lateral muscle of the tobacco hornworm caterpillar, Manduca sexta. Uniaxial loading–unloading shows that the tissue is capable of large nonlinear pseudo-elastic deformations, has a hysteretic behavior and displays stress softening during the first few cycles of repeated loading. The data are used to develop a constitutive model that accounts for the observed material response, including a continuous transition from passive to active states. We consider the material initially incompressible, pseudo-elastic and transversely isotropic with preferred orientation parallel to the longitudinal direction of the muscle. The constitutive formulation is then generalized to account for slightly compressible materials and adapted for finite element implementation. The corresponding incremental equations and the associated isochoric and volumetric parts of the elasticity tensor are derived. To account for pseudo-elasticty, the isochoric part is modified accordingly. The simulation of a bio-actuated micro-pump is used to validate and demonstrate the capability of the model.