Which MAT to use for brittle material

Altair Forum User

Hello! I’m trying to do a simple simulation of distributed force on aluminosilicate glass (E=74 kN/mm^2) with RADIOSS bulk data.

1. Can you tell me what MAT is suitable as I couldn’t find one that especially refers to brittle materials? (The closest I could find is MAT1 or MATX27)
   
2. How do I create distributed load? Do I make separately put a force on each node?
   

Thank you in advance.

Rahul_P1

You can apply a distributed load by dividing the load by the number of nodes and applying this value to each node,

 

perhaps law 27, however I would suggest you see the RADIOSS theory manual, chapter 8 - within RADIOSS help, just go to 

RADIOSS > Theory Manual:

Large Displacement Finite Element Analysis

Altair Forum User

Thank you for your kind reply J . Can you also advice me on

1. A simpler explanation for bulk and block data. I have read this forum page http://forum.altairhyperworks.com/index.php?/topic/1813-the-difference-between-bulk-and-block-format/
   Is block data more for big, sudden impact compared to bulk data?
2. What information do I need to decide whether my analysis should use bulk or block data?

Rahul_P1

we no longer have the differentiation between RADIOSS bulk and block,

 

HyperWorks ships with two major structural solvers, namely Optistruct and RADIOSS

 

You will use Optistruct for implicit analysis and optimization and RADIOSS for explicit FEA to put it simply, so you can make the choice based on if it is implict or explicit analysis that you need to do,

 

Although there are a range of problems which can be solved with either implicit or explicit solutions, generally, the higher the velocity of the model components, the more suitably it can be modeled with explicit equations. The same is true for the amount of material and geometric nonlinearity. in this way you know when to use explicit solver i.e RADIOSS

 

OptiStruct includes analysis disciplines

such as:

• Linear static analysis

• Nonlinear implicit quasi-static analysis

• Linear buckling analysis

• Normal modes analysis

• Complex eigenvalue analysis

• Frequency response analysis

• Random response analysis

• Linear transient response analysis

• Geometric nonlinear implicit analysis

• Linear fluid-structure coupled (acoustic) analysis

• Linear steady-state heat transfer analysis

• Coupled thermal-structural analysis

• Nonlinear steady-state heat transfer analysis

• Linear transient heat transfer analysis

• Contact-based thermal analysis

• Inertia relief analysis with static, nonlinear contact, modal frequency response, and modal transient response analyses

• Component Mode Synthesis (CMS) for the generation of flexible bodies for multi-body dynamics analysis

• Reduced matrix generation

• One-step (inverse) sheet metal stamping analysis

• Fatigue analysis

A typical set of finite elements including shell, solid, bar, scalar, and rigid elements as well as loads and materials are available for

modeling complex events.

• Multi-body dynamics solutions integrated via OptiStruct for rigid and flexible bodies include:

• Kinematics analysis

• Dynamics analysis

• Static and quasi-static analysis

• Linearization

All typical types of constraints like joints, gears, couplers, user-defined constraints, and high-pair joints can be defined. High

pair joints include point-to-curve, point-to-surface, curve-to-curve, curve-to-surface, and surface-to-surface constraints. They

can connect rigid bodies, flexible bodies, or rigid and flexible bodies. For this multi-body dynamics solution, the power of Altair

MotionSolve has been integrated with OptiStruct.

 

 

Finite element solutions via Altair RADIOSS include:

 

• Explicit dynamic analysis

• Nonlinear implicit static analysis

• Transient heat transfer and thermo-mechanical coupling

• Explicit Arbitrary Euler-Lagrangian (ALE) formulation

• Explicit Computational Fluid Dynamics (CFD)

• Smooth Particle Hydrodynamics (SPH)

• Incremental sheet metal stamping analysis with mesh adaptivity

• Linear static analysis

• Normal modes analysis

• Linear and nonlinear buckling analysis

Altair Forum User

thank you for your swift reply. if you don't mind please let me ask some more questions. i would like to simulate distributed forces acting on the center on the top of a simple square solid glass which is placed on something that doesn't break or move (i.e. rigid body).

1) Does constraining dof1,2,3,4,5,6 on all the nodes on the bottom of the glass model ( a simple square solid) does the trick?

2) If the answer for question 1) is yes, is this true regardless of the mesh size?

Rahul_P1

When you place one object on another, it is still possible that the object can slide on it, if this is also not possible in your model, then constraining is one way to go and it is irrespective of reasonable variations in the mesh size. 

You can create a rigid body and then use contacts, 

 

you can easily create rigid bodies in RADIOSS

 

you can create a plate of shell elements and give it very high modulus so that it behaves like a rigid in Optistruct.