04.11 / CDS User Guide
Explore capacity and trade-offs
without losing the assumptions.
Practical operation of Response, failure envelopes, progressive failure, 2D/3D carpet plots, lamina/micro studies, laminate searches and saved optimization evidence.
Complete manuals · download a whole collection
Each collection includes an editable Word manual and its matching searchable PDF, with linked contents, explanatory text, diagrams and references. Theory equations use native Word mathematics. Individual-page PDF buttons remain available.
These are dated reading editions of the public learning content. Interactive studies and account-controlled classroom notes and databases stay online. For current changes, follow the chapter links back to the website.
Current Workbench, reference editions and downloads
Use the online User Guide for current controls, the released model directory for selectable models and compatibility, and the Training Manual for connected exercises. Wider theory references do not mean every formulation is enabled in Workbench.
Dated GUI captures and compiled Web r18 PDF manuals retain their stated scope; they are not a substitute for current hosted Workbench instructions. Find the overview PDF, guides and exercise databases in Your CDS library.
Read the WB equations and limitations →
Stored ply properties bypass Micro. Mixed stacks keep both paths. Gray blocks are not selected. Geometry, process schedules and other model records are omitted here for clarity; a real run must include all required references.
Fatigue uses intact CLT endpoint stresses and measured S–N calibration. It is evaluated separately from Run and progressive failure. The dashed handoff is not active: optimization still uses current properties until a degradation law is supplied.
Materials → Micro → Laminate.
All exercises, case studies and simulation examples → · Your CDS library: overview, manuals and database downloads →
Explore a failure step and explain a hotspot
The slider above the progressive 2D plot is connected to its cursor. Drag either to inspect a saved step; the arrow controls jump between activations. The depth selector sits with the other plot controls.
- Select the step and ply, then expand Explain selected hotspot for its criterion, mode, local stress and theory link.
- Use the vertical Fiber, Matrix and Shear strip: gray means not activated, color means activated, and a gold outline marks a new activation at this step. Select a strip segment to inspect that ply.
- Use the output expand control for more space and restore Split when returning to input editing.
Include delamination in progressive steps
The ordinary CLT progressive ramp degrades plies; it does not separate their interfaces. For supported coupled growth, choose Layerwise x-z plane strain and set Delamination model to Coupled growth.
- Link finite Plate geometry and a laminate with complete 3D stiffness.
- Supply calibrated interface stiffness, normal/shear strengths, fracture energies and BK exponent, plus ply strengths and load-step controls. No interface properties are inferred from a laminate name.
- Run the linked simulation, then open Response → Progressive failure · plies + delamination.
- Check mesh and step convergence and compare with the connected simulation-20 exercise and cohesive theory.
Optimization cases: Micro, Process and Laminate
Optimizations contains Micro, Process and Laminate subfolders. New saved cases retain the numerical study, all search variables and constraints, and a frozen archive of linked source records and process boundary schedules. Older snapshots remain readable but cannot recover source records that were never saved.
- Configure and run the selected optimizer, name the case and choose Save snapshot. The case is added to its mode folder and downloaded as a CDS_DB. Save the workspace as well to retain all cases together.
- Reopen the case and expand All saved optimization inputs. Inspect search variables, objectives and constraints; effective solver properties and loads; linked material, model, laminate, geometry and case records where used; and saved process schedules.
- The archived source records document the database at save time. Effective solver inputs separately preserve selected overrides and the values actually supplied to the optimizer. These two views need not be identical.
- Use the shared exercise tree and search for optimization: Micro stiffness, voids and density; Laminate minimum mass under axial loading; Process cycle time and thermal uniformity. The same exercise IDs and instructions appear in Workbench Training, this manual and licensed CDS_DB downloads.
Start from a checked structural case
Select the structural load case and verify its linked laminate. Failure and optimization need elastic ply properties and compatible strength allowables, not just a plausible-looking layup.
- In Input: CASES, review Loads and Failure. Select which Nx, Ny, Nxy, Mx, My and Mxy components ramp; the same load selection is reflected in the diagram and failure controls.
- Check the actual numbers and signs. The WB optimizer shows membrane resultants in N/mm and moments in N; a source record in N/m is converted for this calculation.
- Do not treat pressure, point force or torque labels as an automatic replacement for membrane/bending resultants. Resolve the load case into the quantities required by the selected analysis.
- Review missing-input diagnostics and the ply strength table. Unsupported or incomplete theories must not be interpreted as zero failure index.
Read stress and strain before failure
Response gives through-thickness stress and strain in selected components and coordinates. Compare like contributions at the same process time.
- Choose response source, global or local axes, components and scale. See screenshot
- Select thickness from bottom or the available alternate depth coordinate. Inspect ply interfaces and angle labels. See screenshot
- Increase recovery nodes per ply in Settings when more sampling is useful, then check that the result source is still appropriate.
- Use the resizable output region and axis locks to inspect the complete plot. See screenshot
Build and interpret a failure envelope
An envelope traces first-failure capacity in a selected pair of load components. Each ray is evaluated with the selected material criterion and laminate response; the displayed curve joins sampled directions.
- Choose the envelope axes, supported theories and the fixed/background load state in Failure inputs.
- Generate or update the envelope; inspect the completion/evaluation status and units.
- Right-click the envelope plot to show markers when you need to see the calculated samples.
- Compare criteria only when each has valid material data. A curve farther from the origin is not proof that its theory is more accurate.
Follow progressive failure
Progressive analysis ramps the selected loads, evaluates ply criteria and updates damage/stiffness according to the chosen method. First-ply failure and last-ply/terminal response answer different questions.
- Set criterion, ramp, step count, search limit and stopping rule in the Failure inputs.
- Choose whether saved thermal/cure effects, cure shrinkage and moisture expansion are reused; rerun the relevant solver after changing those inputs.
- Read first activations, damaged plies, load factor and retained stiffness together.
- Use the selected event, ply and pseudo-time controls to inspect the corresponding response. Pseudo-time in the proportional ramp is the load multiplier, not seconds.
Explore elastic design space with 2D and 3D carpet plots
Carpet plots sweep two existing absolute-angle families while retaining ply materials, thicknesses, ordering and angle signs. Choose two different outputs such as Ex, Ey, Gxy, νxy, A11/A22 or D11/D22, then select a 2D carpet or 3D surface.
- Choose distinct α and β families already present in the laminate and set increasing 0–90° bounds with 2–21 samples per sweep. See screenshot
- In 3D, choose which sweep lies in the plane and which output is vertical. Filled surfaces default on at 55% opacity; switch fill, mesh, autoscale, extrema and other display aids independently. See screenshot
- Drag the divider to give controls or plot more room. The 2D/3D selector stays at the top, and the live laminate remains beside the 3D plot. See screenshot
- Hover a point to inspect the exact color-coded candidate. Display minima and maxima when locating the evaluated extrema, then verify balance, symmetry and manufacturability for that candidate. See screenshot
Optimize lamina and microstructure inputs
Lamina / Micro mode builds the same 2D and 3D study workflow around microstructure inputs rather than ply angles. It uses the selected micromechanics model, linked constituents, editable empirical parameters, and available thermal or moisture data.
- Choose the micromechanics record and confirm its linked fiber, matrix, filler or void records. Missing required inputs stop the study instead of silently substituting a hidden constant.
- Select two inputs from the variables relevant to that model: composition, aspect ratio, orientation, crimp, weave or braid terms, void knockdown, constituent-retention factors, or editable transport closures.
- Choose elastic, strength, density, specific heat, conductivity, thermal diffusivity, moisture diffusivity or moisture saturation as the mapped output.
- Set bounds, fixed slices and constraints. Use 2D contours or filled 3D surfaces with extrema and autoscale controls to examine maxima, minima and trade-offs.
- Save the snapshot before applying a candidate. Applying writes the chosen active model parameters back to the micromechanics record; downstream laminate and structural results should then be rerun.
Run a bounded laminate optimization
Laminate mode searches discrete ply angles for a selected mechanical load case. Objectives are lowest feasible areal mass, greatest first-failure load factor, or greatest absolute selected mid-plane strain at first failure.
- Choose Laminate in Optimize Inputs, then select the structural case, objective, first-ply criterion, allowed angles and required load factor.
- For mass, set minimum/maximum ply counts. Strength and strain hold the current ply count fixed.
- Choose symmetric construction, balanced pairs and minimum angle content as needed. Review the angle-content guidance.
- Set a repeatable seed and evaluation budget in Search settings. The supported range is 1–64 plies and 20–2000 evaluations.
- Click Optimize. Read evaluated/feasible counts, convergence, trade-off plot and Best Found together. Drag the panel dividers to inspect the plots.
- Apply candidate updates the existing laminate after confirmation. Create new laminate creates a separate candidate-based record and leaves the original laminate and simulation link unchanged. Both actions remain disabled until a feasible candidate is available.
Save and compare optimization cases
Use Save snapshot in Inputs, beside the structural-case dropdown, after a result is available. Name the case so its objective and loading are recognizable.
- Saving captures the inputs, load vector, search settings, candidates, convergence and best-found result; it also provides a CDS_DB download.
- Open a saved case from Optimizations below Simulations. Saved inputs are read-only.
- Select multiple cases for the comparison table and Ashby, bar or line views. Use axis properties and filters just as in Materials results.
- Start New optimization for a fresh search. Changing current inputs does not rewrite an earlier snapshot.
Know what the search does not establish
Small spaces are exhaustively enumerated; larger spaces use seeded multi-start search. A budget limit or flat convergence curve is not proof of a global optimum.
- Repeat large searches with different seeds and budgets.
- Check contiguity, disorientation, manufacturing rules and damage tolerance separately.
- Validate buckling, fatigue, joints, defects, delamination and environmental effects with suitable models and data.
- Treat any claimed “best” design as best found within this defined search space and model.
Workbench availability: released models, inputs and compatible study paths. The wider theory library includes reference formulations not available in every Workbench solve.