On parameter identification for material and microstructural properties

Abstract

The simulation of the mechanical behaviour of structures with the finite element method is one of the main tasks in engineering mechanics and requires both constitutive and structural parameters. In addition to a qualified geometrical approximation of the structure with the finite element discretization and the definition of initial and boundary conditions it is necessary to select material models for the realistic description of the mechanical system at hand. Furthermore, the material models chosen require reliable numerical data for the associated constitutive parameters, which are usually not known for most new materials like reinforced composites, if their properties are not listed in a database or if they consist of different constituents. Composites usually possess unknown microstructural properties, which cannot be assigned to typical specimen of homogeneous material distribution. Due to the imperfect manufacturing process the mechanical behaviour of composites can significantly vary and the associated material parameters must be determined from the overall behaviour of the composite. Therefore, the unknown material parameters, as the essential input data for the consitutive model for every finite element simulation, must be identified by solving an inverse problem before the complete structure is analyzed.

Identification of the Extended Standard Linear Solid Material Model by Means of Experimental Dynamical Measurements

“…Numerical parametric identification of the parameters of a SLS model is a non-trivial task and some techniques were proposed in the past [32][33][34][35][36]. It should be outlined that the model identification task associated to N > 2 may be difficult from the experimental and computational standpoint, since the resulting high number of unknown parameters to be identified may require many test measurements in an extended Ω range and an ill conditioned system of nonlinear equations may result in the identification problem.…”

Effective properties and size effects in filled polymers

“…Nevertheless, the material properties in the interphase region are distributed inhomogeneously on the microscale and this distribution strongly influences the overall behaviour of the filled polymer [13,17,20,25,26]. On the RVE scale an existing interphase can be incorporated phenomenologically [39,10,17]. Often surface modifications of the filler particles are studied with respect to changes in the adhesive properties [8,31,22].…”

Effective Mechanical Behavior of Filled Polymers

“…There are also some authors who incorporated an existing interphase phenomenologically, cf. [16,21,22]. Others investigated the filler particles with respect to surface modifications [23][24][25].…”