Composite Properties

Layer (Ply) Number N (Nply_ID_i) and Integration Points each Layer (Ply)

For layer-based modeling which use /PROP/TYPE10, /TYPE11. N is the number of layers through the shell thickness. For these properties, there is one integration point (IP) each layer.

For ply-based modeling, which use /PROP/TYPE17, /TYPE51 and /PCOMPP. Pply_ID_i is the number of plies through the shell thickness. Plies could be combined until n plies for these properties.

For TYPE17 only one integration point is allowed while for TYPE51 and /STACKF until 9 integration points are allowed. Number of integration point defined with option “Npt_ply” in property TYPE19 or /PLY.

Example (Ply) (/PROP/TYPE51)

In this example, Npt_ply=3 defined in /PROP/TYPE19, means 3 integration points defined per ply and with option I_int=0 defined in /PROP/TYPE51, then these 3 integration points are uniformly distributed through each ply thickness.

Figure 5.

If I_int=1 in /PROP/TYPE51, then integration points are distributed follow Forces and Moments Calculation Gauss Integration Scheme through each ply thickness.

Figure 6.

It is possible to print animation results (plastic strain, damage, stress and strain tensor) in each specific integration point with /ANIM/SHELL/IDPLY/Keyword4/I/J (or /ANIM/SHELL/Keyword3/N/NIP).

For instance, use /ANIM/SHELL/IDPLY/EPSP/2/3 (or /ANIM/SHELL/EPSP/2/3) to print plastic strain in third integration point (red highlighted integration point in Figure 6) of second ply (ply name Ply12). For additional print info about Integration points through shell thickness for composite properties, refer to How is the generalized stress tensor /ANIM/SHELL/TENS/MEMB and /ANIM/SHELL/TENS/BEND computed? in the FAQs.

Anisotrophy in Layer (Ply)

• The first anisotropic direction of material could be defined with angle $$\varphi$$ and gloval vector $$V$$(V_X,V_Y,V_Z). It is also possible to use angle $$\varphi$$ and skew. In this case, x-axis of skew replaced the global vector $$V$$.

  Project the global vector $$V$$ in shell element and then rotate $$\varphi$$ degree is the first anisotropic direction (also called Material direction 1). The positive direction of $$\varphi$$ is coding to shell normal $$n$$. For example, in Figure 7 rotate counterclockwise $$\varphi$$ degree is material direction 1.

  The material direction 1 of the local element reference is normally the fiber direction. Then the material character (E-Module, yield stress, and so on) of direction 1 which defined in material law could be then applied in the correct direction on local element reference.

  
  
  Figure 7.

• Composite material could be orthotropic or anisotropic. In Radioss it is possible to describe this character with anisotropic axis angle ${\alpha }_i$ in ply-based properties. In case of ${\alpha }_i={90}^{\circ }$, then it describes orthotropic material. For layer based properties (TYPE10 and TYPE11) which without this option ${\alpha }_i$, so that only orthotropic material could be defined.

  
  
  Figure 8.

  Figure 9 shows an Example in /PROP/TYPE11 which use skew to define global vector $$V$$.

  
  
  Figure 9.

  For property TYPE11 and TYPE51, the anisotropic direction for some shell could also be initialized with $$\varphi$$ in keyword /INISHE/ORTH_LOC or /INISH3/ORTH_LOC. For property TYPE51, anisotropic axis angle could also be initialized with these keywords.

• The orientation of anisotropy for specific shell elements or shell element groups could be change again with option drape_ID and def_orth in /PROP/TYPE19 and /PLY. drape_ID defined in /DRAPE. With this feature, angle of anisotropic direction could be changed with ${\theta }_{drape}$.
  • If use def_orth=1:
    Angle ${\varphi }_i$, skew or global vector $$V$$ will be ignored. Take shell local x-axis as vector $$V\text{'}$$ and then rotate $$\varphi$$ degree is the first anisotropic direction. ${\varphi }_s$ (defined in /SHELL or /SH3N) is taken into account by compute angle $$\varphi$$.(1) $$\varphi ={\varphi }_s+\text{Δ}\varphi +{\theta }_{drape}$$
  • If use def_orth=2 (Default)
    Project the global vector $$V$$ in shell element to vector $$V\text{'}$$ and then rotate $$\varphi$$ degree is the first anisotropic direction. The angle $$\varphi$$ is computed as:(2) $$\varphi ={\varphi }_i+\text{Δ}\varphi +{\theta }_{drape}$$

    
    
    Figure 10.

Layer (Ply) Thickness and Position

• For /PROP/TYPE10, layer thickness is simply averaged by layer number(3) $t_i=Thick/N$
  and layers are automatically overlying one by one from bottom to top.

  
  
  Figure 11.

• For property TYPE11, TYPE17, TYPE51 and /STACK, layer (ply) position and thickness depend on option I_pos
  • If I_pos=0
    User layer (ply) thickness input $t_i$ will be taken, and layer (ply) position will be automatically overlying one by one from bottom till top; but if,(4) ${\displaystyle \sum _i{t}_i}\ne Thick$
    Then, layer (ply) thickness will be adjusted to $t_i^{new}$, so that(5) ${\displaystyle \sum _i{t}_i^{new}}=Thick$

    Layer (ply) position will be then adjusted, as well.

  • If I_pos=1

    User layer(ply) input of thickness $t_i$ and position $Z_i$ will be taken. Sum of layer thickness will not be checked with $Thick$.

    For additional information, refer to How does Radioss calculate layer thickness and layer position in /PROP/TYPE11 and /PROP/TYPE16? in the FAQs.

• For property TYPE17, TYPE51 and /STACK, it is also possible to offset the plies with I_pos=2, 3, 4
  • I_pos=2: the shell element mid-surface is at Z₀ from the bottom of the ply layout

    
    
    Figure 12.

  • I_pos=3: the top of the ply layout is coincident with the element mid-surface

    
    
    Figure 13.

  • I_pos=4: the bottom of the ply layout is coincident with the element mid-surface

    
    
    Figure 14.

• For /PROP/TYPE17, /PROP/TYPE51 and /STACK, ply thickness could be changed by option $Thinning$ in /DRAPE (which is used in /PROP/TYPE19 or /PLY). Then updated ply thickness is: (6) $t_i^{new}=t_i\cdot Thinning$

Composite Material Used for Layer (Ply)

The new composite technology allows you to make parts production more and thicker, as modeling those parts with shell elements is not enough. Thick shell can solve this problem. Compare with shell element, thick shell could direct connect with other solid part.

Anisotrophy in Layer (Ply)

Similar to shell property /PROP/TYPE11, reference vector $$V$$ and angle $$\varphi$$ are used to define the material direction 1. The reference vector $$V$$ project to the middle surface of solid element and turn $$\varphi$$ degree is the material direction 1.

Figure 17.

Layer Thickness and Position

For solid element thickness and position defined by element mesh.

Composite Material Used for Layer

For additional information, refer to “Composite material and Composite failure”.