6.2 Total Strain Crack Models

This section details the syntax of input for constitutive models based on total strain, also called the `Total Strain crack models', which describe the tensile and compressive behavior of a material with one stress-strain relationship. These models cannot be combined with other constitutive models. However, combination with ambient influence is possible. This makes the models very well suited for Serviceability Limit State (SLS) and Ultimate Limit State (ULS) analyses which are predominantly governed by cracking or crushing of the material. See §18.2 for background theory. See also §5.1.3 for Rankine plasticity models.

Input data.

The input for the Total Strain crack models comprises two parts: (1) the basic properties like the Young's modulus, Poisson's ratio, etcetera, and (2) the definition of the behavior in tension, shear, and compression.

    (syntax)

TOTCRK

specifies the type of Total Strain model to be used:

FIXED

for the Total Strain Fixed crack model [§18.2.1].

ROTATE

for the Total Strain Rotating crack model [§18.2.1].

These formulations describe the cracking and crushing behavior of the material with a nonlinear elasticity relationship.

Basic properties

can be derived from Model Code regulations for concrete or you may input them directly [§6.2.1].

By default DIANA assumes appropriate values for the various parameters describing the constitutive behavior. However, you may specify the following optional input data to customize the constitutive behavior and overrule the defaults.

Tensile behavior

describes the material response in tension, which usually is cracking [§6.2.2].

Shear behavior

describes how the shear behavior changes when the material is cracked.

Compressive behavior

describes the crushing behavior of the material within the same concept as the tensile behavior [§6.2.4].

Lateral influence

models may be applied within a concept based on total strain to describe the effect of lateral cracking or lateral confinement [§6.2.5].

For appropriate input see the referenced sections [Table 6.1].

Table 6.1: INPUT FOR TOTAL STRAIN CRACK MODELS

			FIXED	ROTATE
Basic	code	§6.2.1.1	yes	yes
	direct	§6.2.1.2	yes	yes
Tensile	predefined	§6.2.2.1	yes	yes
	user-supplied	§6.2.2.2	yes	yes
Shear	constant	§6.2.3.1	yes	-
	variable	§6.2.3.2	yes	-
Compression	predefined	§6.2.4.1	yes	yes
	user-supplied	§6.2.4.2	yes	yes
Lateral		§6.2.5	yes	yes