Materials input data are only given as examples and should NOT be used in the design.
Input data is for shell elements only. Solid elements-specific parameters (if any) are ignored
AOPT input is not provided, as it is case-dependent.
| Parameter | Meaning | Units | Sample Input for Hexcel IM7/8552 | Comment for the chosen value |
|---|---|---|---|---|
| RO | Mass density | kg/mm3 | 1.58e-6 | |
| EA | Young's modulus in a-direction. This is the modulus along the direction of fibers. | MPa | 165000 | WWFE data |
| EB | Young's modulus in b-direction. This is the modulus transverse to fibers. | MPa | 9000 | WWFE data |
| PRBA | Poisson's ratio, ba (minor in-plane Poisson's ratio). | -- | 0.0185 | WWFE data |
| PRCB | Poisson's ratio, cb (Poisson's ratio in the plane of isotropy). | -- | 0.5 | WWFE data |
| GAB | Shear modulus, ab (in-plane shear modulus). | MPa | 5600 | |
| NLAYER | Number of layers in the sub-laminate excluding symmetry. As an example, in a [0/45/-45/90]3s, NLAYER = 4. | -- | 4 | A stacking sequence of [902 (0.135mmx2) / (+45/-45)2 ({0.135+0.135}x2) / 02 (0.135x2)]s cannot be precisely represented in this model, however it can be approximated as [90(0.27mm) / +45 (0.27mm) / -45 (0.27mm) / 0 (0.27mm)]s |
| R1 | Non-local averaging radius. | mm | 2.0 | As determined for the same material system and a similar (quasi-isotropic) layup in Ref. |
| NFREQ | Number of time steps between update of neighbor list for nonlocal smoothing.
EQ.0: Do only one search at the start of the calculation. |
-- | 0.0 | |
| ANGLEi | Rotation angle in degrees of layers with respect to the material axes. Input one for each layer. | deg. | [90 / 45 / -45 / 0] | This parameter is layup-specific! |
| IMATT | Initiation strain for damage in matrix (transverse) under tensile condition. | mm/mm | 0.008 | Taken as determined in Ref. for the same material system. Approximately, it should correspond to onset of non-linear part of sigma-epsilon curve of a ply loaded in transverse (90deg.) direction. Often, has lower value than failure strain of a ply in fiber direction. |
| IFIBT | Initiation strain for damage in fiber (longitudinal) under tensile condition. | mm/mm | 0.011 | Taken as determined in Ref. for the same material system. Approximately, should be equal to the failure strain of a ply in fiber direction. |
| ILOCT | Initiation strain for the anti-locking mechanism. | mm/mm | 0.15 | This parameter should be equal to the saturation strain for the fiber damage mechanism under tensile condition (SFIBT). |
| SMATT | Saturation strain for damage in matrix (transverse) under tensile condition. | mm/mm | 0.15 | Taken as determined in Ref. for the same material system. |
| SFIBT | Saturation strain for damage in fiber (longitudinal) under tensile condition. | mm/mm | 0.15 | Taken as determined in Ref. for the same material system. |
| SLOCT | Saturation strain for the anti-locking mechanism under tensile condition. | mm/mm | 0.17 | The recommended value for this parameter is (ILOCT+0.02). |
| IMATC | Initiation strain for damage in matrix (transverse) under compressive condition. | mm/mm | 0.0087 | Taken the same as IFIBC as recommended in Ref. (page 14), due to the fact that in the kinking process, matrix cracking and fibre breakage/bending initiate simultaneously. Therefore, this parameter is NOT equal to strain of a ply at transverse compressive strength! |
| IFIBC | Initiation strain for damage in fiber (longitudinal) under compressive condition. | mm/mm | 0.011 | Assumed the same as strain at longitudinal compressive strength (Ref.) |
| ILOCC | Initiation strain for the anti-locking mechanism. | mm/mm | 0.02 | This parameter should be equal to the saturation strain for the fiber damage mechanism under compressive condition (SFIBC). |
| SMATC | Saturation strain for damage in matrix (transverse) under compressive condition. | mm/mm | 0.02 | As recommended in Ref. (page 15) for 2mm-thick IM7/8552 laminates. For 4 mm - 0.03; for 6 mm - 0.035; for 8 mm - 0.04. Physical basis for thickness dependence: In the kinking failure process, the saturation strain depends on the laminate thickness. By increasing the laminate thickness, the magnitude of the through-thickness compressive stress increases. This stress provides lateral support for the fibres and thus effectively increases the saturation strain corresponding to the kinking damage process. |
| SFIBC | Saturation strain for damage in fiber (longitudinal) under compressive condition. | mm/mm | 0.02 | Assumed to be the same as SMATC, as in Ref. (page 16) |
| SLOCC | Saturation strain for the anti-locking mechanism under compressive condition. | mm/mm | 0.04 | The recommended value for this parameter is (ILOCC+0.02). |
| ERODE | Erosion Flag
EQ.0: Erosion is turned off. EQ.1: Non-local strain based erosion criterion. EQ.2: Local strain based erosion criterion. EQ.3: Use both ERODE = 1 and ERODE = 2 criteria. |
-- | EQ.1 | When ERODE > 0, an erosion criterion is checked at each integration point. Shell elements and thick shell elements will be deleted when the erosion criterion has been met at all integration points. For ERODE = 1, the erosion criterion is met when maximum principal strain exceeds either SLOCT×ERPAR1 for elements in tension, or SLOCC×ERPAR1 for elements in compression. Elements are in tension when the magnitude of the first principal strain is greater than the magnitude of the third principal strain and in compression when the third principal strain is larger. When R>0, the ERODE = 1 criterion is checked using the non-local (averaged) principal strain. For ERODE = 2, the erosion criterion is met when the local (non-averaged) maximum principal strain exceeds ERPAR2. For ERODE = 3, both of these erosion criteria are checked. For visualization purposes, the ratio of the maximum principal strain over the limit is stored in the location of plastic strain which is written by default to the elout and d3plot files. |
| ERPAR1 | The erosion parameter #1 used in ERODE types 1 and 3. | mm/mm | 1.2 | ERPAR1>=1.0 and the recommended value is ERPAR1 = 1.2. |
| ERPAR2 | The erosion parameter #2 used in ERODE types 2 and 3. | mm/mm | no input | The recommended value is five times SLOCC defined in cards 7 and 8. |
| RESIDS | Residual strength for layer damage. | MPa | no input | Effect of residual stresses not considered. |