04.12.1 / CDS Training Manual

Predict T700/PR520
effective lamina properties.

A bottom-up micromechanics study using constituent values and three fiber-volume regions published for a NASA triaxial-braid model.

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Predict T700/PR520 effective lamina properties. two-row simulation workflow with connected input blocks, fatigue and optimization — Two-row simulation workflow · Open full-size map ↗
Linked-input preview, not solved results. Gray blocks are not configured.

Reference validation · 2026-09-18

Not benchmark validated

No matched quantitative reference comparison completed for the full exercise.

Recorded baseline only—not a certification of the current database, edited inputs, or every output. Analytical agreement is not experimental material or failure validation.

Source validation, comparisons and tested inputs

Execution: Completed (not validation)

The copied T700/EP180 database is a connected starter, not T700/PR520. Complete the constituent setup below before comparing with NASA.

NASA/TM—2015-218814 — Experimental and Numerical Analysis of Triaxially Braided Composites Utilizing a Modified Subcell Modeling Approach ↗Tables 3–4, printed page 7 / PDF page 11. MAC/GMC calculated effective ply data, not measured UD coupon properties.

Tested inputs

Input SHA-256: f332a9c41bf7dc1aaa5eb2521be80c1e6feeef085db48ea61d81a3475b42b7b9
Solver source SHA-256: 30c8a614b6cb004a26da8adaf8ab7c534c37c4d534836921939f35a549e1bcc5

Constituent-to-lamina screening only. The NASA braid subcells, calibrated LS-DYNA damage and coupon validation are not reproduced.

Separate published-data fixture: Benchmark discrepancy

Source-matched constituent fixture compared with NASA MAC/GMC, 1% exploratory equivalence criterion declared before running. A different homogenization model need not match; mismatch is retained, not fitted away.

Acceptance: absolute error ≤ absolute tolerance + relative tolerance × |reference|.
Quantity	CDS	Reference	Error %	Tolerance (relative + absolute)	Result
E1 at Vf=0.375 (GPa)	88.75	88.5	0.2824859	1% + 0.00002 GPa	Pass
E2 at Vf=0.375 (GPa)	5.51724	6.22	-11.29839	1% + 0.00002 GPa	Discrepancy
G12 at Vf=0.375 (GPa)	2.23256	2.6	-14.13231	1% + 0.00002 GPa	Discrepancy
E1 at Vf=0.733 (GPa)	169.658	169.5	0.09321534	1% + 0.00002 GPa	Pass
E2 at Vf=0.733 (GPa)	8.64927	9.9	-12.63364	1% + 0.00002 GPa	Discrepancy
G12 at Vf=0.733 (GPa)	4.70445	7	-32.79357	1% + 0.00002 GPa	Discrepancy
E1 at Vf=0.8 (GPa)	184.8	184.7	0.05414185	1% + 0.00002 GPa	Pass
E2 at Vf=0.8 (GPa)	9.67742	10.9	-11.21633	1% + 0.00002 GPa	Discrepancy
G12 at Vf=0.8 (GPa)	5.93407	6	-1.098833	1% + 0.00002 GPa	Discrepancy

NASA/TM—2015-218814 — Experimental and Numerical Analysis of Triaxially Braided Composites Utilizing a Modified Subcell Modeling Approach ↗Tables 3–4, printed page 7 / PDF page 11. MAC/GMC calculated effective ply data, not measured UD coupon properties.

Fixture inputs

{
  "fiber": {
    "E1": 230,
    "E2": 15,
    "G12": 27,
    "nu12": 0.2
  },
  "matrix": {
    "E": 4,
    "G": 1.44,
    "nu": 0.38
  },
  "volumeFractions": [
    0.375,
    0.733,
    0.8
  ],
  "voidFraction": 0,
  "model": "Rule of mixtures"
}

Separate published-data fixture: Benchmark discrepancy

Acceptance: absolute error ≤ absolute tolerance + relative tolerance × |reference|.
Quantity	CDS	Reference	Error %	Tolerance (relative + absolute)	Result
E1 at Vf=0.375 (GPa)	88.75	88.5	0.2824859	1% + 0.00002 GPa	Pass
E2 at Vf=0.375 (GPa)	6.62252	6.22	6.471383	1% + 0.00002 GPa	Discrepancy
G12 at Vf=0.375 (GPa)	2.90406	2.6	11.69462	1% + 0.00002 GPa	Discrepancy
E1 at Vf=0.733 (GPa)	169.658	169.5	0.09321534	1% + 0.00002 GPa	Pass
E2 at Vf=0.733 (GPa)	10.47761	9.9	5.834444	1% + 0.00002 GPa	Discrepancy
G12 at Vf=0.733 (GPa)	7.00011	7	0.001571429	1% + 0.00002 GPa	Pass
E1 at Vf=0.8 (GPa)	184.8	184.7	0.05414185	1% + 0.00002 GPa	Pass
E2 at Vf=0.8 (GPa)	11.43662	10.9	4.923119	1% + 0.00002 GPa	Discrepancy
G12 at Vf=0.8 (GPa)	8.80865	6	46.81083	1% + 0.00002 GPa	Discrepancy

NASA/TM—2015-218814 — Experimental and Numerical Analysis of Triaxially Braided Composites Utilizing a Modified Subcell Modeling Approach ↗Tables 3–4, printed page 7 / PDF page 11. MAC/GMC calculated effective ply data, not measured UD coupon properties.

Fixture inputs

{
  "fiber": {
    "E1": 230,
    "E2": 15,
    "G12": 27,
    "nu12": 0.2
  },
  "matrix": {
    "E": 4,
    "G": 1.44,
    "nu": 0.38
  },
  "volumeFractions": [
    0.375,
    0.733,
    0.8
  ],
  "voidFraction": 0,
  "model": "Halpin–Tsai model"
}

Download source-validation evidence (JSON) · Full 104-exercise study

Objective

Predict how T700/PR520 effective ply stiffness changes across the three local fiber-volume regions used in NASA’s absorbed-matrix braid model.

CDS scope

CDS reproduces a constituent-to-lamina comparison. It does not reproduce the report’s complete braid subcell, LS-DYNA damage calibration, or coupon validation.

Published basis

1 primary source

NASA/TM—2015-218814Experimental and Numerical Analysis of Triaxially Braided Composites Utilizing a Modified Subcell Modeling Approach

Tables 3 and 4 provide T700 and PR520 constituent properties and MAC/GMC effective-ply values for Vf = 37.5%, 73.3% and 80%.

Starting data

Enter in the displayed units

Variable	Value	How it is used
T700 density	1.80 g/cm³	Fiber physical property
T700 E1 / E2	230 / 15 GPa	Fiber axial and transverse modulus
T700 ν12 / G12	0.20 / 27 GPa	Fiber coupling and shear
PR520 density	1.25 g/cm³	Matrix physical property
PR520 E / ν / G	4.0 GPa / 0.38 / 1.44 GPa	Isotropic matrix elasticity
Fiber volume fractions	37.5%, 73.3%, 80.0%	Three separate micromechanics evaluations

Review checkpoints

Comparison, not certification

Result	Published reference	Interpretation
Vf 37.5%: E1 / E2 / G12	88.5 / 6.22 / 2.60 GPa	B-braider effective ply
Vf 73.3%: E1 / E2 / G12	169.5 / 9.90 / 7.00 GPa	A/C-braider effective ply
Vf 80.0%: E1 / E2 / G12	184.7 / 10.9 / 6.00 GPa	A-axial effective ply

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Create traceable constituent records

Duplicate the nearest carbon-fiber and thermoset records so the library baselines remain unchanged.

Name the records T700 — NASA case study and PR520 — NASA case study.
Enter the density and elastic values from the starting-data table. For the isotropic matrix, use E = 4.0 GPa, ν = 0.38 and G = 1.44 GPa.
Add the NASA report as the source, mark the values as published research inputs, and leave unsupported strength or transport terms visibly incomplete.

Link a continuous-fiber micromechanics model

Create or duplicate a unidirectional micromechanics record and link the T700 fiber and PR520 matrix.

Choose a model that reports the full orthotropic lamina stiffness.
Set void fraction to zero for the baseline comparison and keep empirical closure parameters at their documented defaults.
Confirm Live Microstructure and the dependency summary point to the two case-study constituent records.

Sweep the three published fiber fractions

Use Lamina / Micro optimization or three duplicated model records to evaluate Vf = 37.5%, 73.3% and 80.0%.

Hold all other inputs fixed and evaluate each volume fraction.
Plot Vf against E1, E2 and G12; use a line view for the trend and the table for exact values.
Save one optimization snapshot or export one comparison table containing all three cases.

Compare the effective lamina response

Compare CDS output with NASA’s MAC/GMC values in the checkpoint table. Expect the longitudinal trend to be strongest and model-dependent differences in transverse and shear response.

Calculate percent difference as 100 × (CDS − reference) / reference for each modulus.
Inspect the selected model’s assumptions before attributing differences to input data.
Repeat with another supported homogenization model to show model-form sensitivity.

Save the predicted lamina for downstream work

Create a new lamina material from the selected prediction and retain the model and source links.

Choose the fiber fraction appropriate to the intended region rather than averaging the three NASA subcells without justification.
Save the generated material with Prediction status.
Open the new record and verify that its provenance identifies both constituents and the micromechanics model.

Predict T700/PR520effective lamina properties.

Reference validation · 2026-09-18

Tested inputs

Create traceable constituent records

Link a continuous-fiber micromechanics model

Sweep the three published fiber fractions

Compare the effective lamina response

Save the predicted lamina for downstream work

Predict T700/PR520
effective lamina properties.