An explicit is solved by calculating results in small time increments or time steps. The size of the time step depends
on many factors but is automatically calculated by Radioss.
Composite materials consist of two or more materials combined each other. Most composites consist
of two materials, binder (matrix) and reinforcement. Reinforcements come in three forms, particulate,
discontinuous fiber, and continuous fiber.
Describes orthotropic solid material which use the Tsai-Wu formulation. The materials are 3D orthotropic-elastic,
before the Tsai-Wu criterion is reached. LAW12 is a generalization and improvement of LAW14.
LAW25 is the most commonly used composite material in Radioss. It can be used with shell and solid elements. The two formulations available in LAW25 are the Tsai-Wu and CRASURV formulations.
Radioss has two material laws for modeling fabrics LAW19 and LAW58. LAW19 is an elastic orthotropic material and must be used with /PROP/TYPE9. LAW58 is hyperelastic anisotropic fabric material and must be used with /PROP/TYPE16.
Composite could be modeled with solid or shell element. Depending on the element type, the following properties can
be used in Radioss to model a composite.
Optimization in Radioss was introduced in version 13.0. It is implemented by invoking the optimization capabilities of
OptiStruct and simultaneously using the Radioss solver for analysis.
Composite materials consist of two or more materials combined each other. Most composites consist
of two materials, binder (matrix) and reinforcement. Reinforcements come in three forms, particulate,
discontinuous fiber, and continuous fiber.
Radioss has two material laws for modeling fabrics LAW19 and LAW58. LAW19 is an elastic orthotropic material and must be used with /PROP/TYPE9. LAW58 is hyperelastic anisotropic fabric material and must be used with /PROP/TYPE16.
Radioss has two material laws for modeling fabrics
LAW19 and LAW58. LAW19 is an
elastic orthotropic material and must be used with /PROP/TYPE9.
LAW58 is hyperelastic anisotropic fabric material and must be used
with /PROP/TYPE16.
Coupling between warp and weft directions could be defined in this material law to reproduce
physical interaction between fibers. Both material laws are often used for airbag
modeling.
In LAW58, two methods are provided to define the stress-strain behavior.
Nonlinear function (fct_IDi) curve to define the warp, weft and shear
behavior
Young's modulus, soften coefficient B, straightening
strain Si and fiber bending modulus reduction factor
Flexi
In warp and
weft direction:
For in-plane shear in initial
state, use . Once (angle between wrap and weft) reaches (shear lock angle), then use GT to describe the strengthening.
if
if
For out-of-plane shear stress-strain is described with
.
For fabric, there is straight process at the beginning of tension. At this phase, fiber shows
very soft, due to not being tightened yet.
In LAW58, use Flexi to
describe this behavior:(1)
After the fabric is tight (strengthening strain Si is reached), then normal fiber elasticity
Ei could be used.