Objective: To translate optimum Zone-by-Zone Laminate results into a set of part-level Plies, while evaluating the manufacturability of the part (good Ply Shapes and minimal Ply Drops).
Sequencing is the process of connecting Lamina that are shared across multiple adjacent Zones into Plies that can be exported for manufacturing. The HyperX Sequencing process studies many different Ply results to find the most manufacturable solution (considering details such as Ply Drops, Ply Count, and Ply Size). Additionally, Sequencing can trade weight vs manufacturability by swapping out Laminate results for Zones to find solutions that have better compatibility with adjacent Zones.
The purpose of the Sequencing is to assess the manufacturability of the design by converting the Local Plies in each Laminate to Global Plies which are shared between the neighboring Zones. The designs are scored based on manufacturability metrics and the best, most desirable designs are presented to the user.
The image below displays a sequenced result across a single Ply Drop boundary.
HyperX Laminate Sequencing will
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Maintain symmetric and balanced layups in both the thick (left) and thin (right) Laminates and also mostly in the Ply Drop transition joint.
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Drop Ply Layers near the midplane of the layup, but with interleaving as a user selected higher objective. The midplane Ply itself is intentionally not dropped.
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Identify as many continuous full body Plies as possible and reduce the number of drawing Ply part numbers.
HyperX laminate sequencing will not
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Perform Drop-off rate in the Ply Drop transition joint. Other tools such as FiberSIM or CATIA should be used for defining this design data. If a 20 to 1 drop off rate is used, for a 0.005” thick material ply, this would allow 10 plies to drop off in 1.0”.
Annex Optimization
HyperX evaluates different workable solutions for each Zone to return a fully Sequenced result for the entire Structure. Since each Zone in the Structure may have many workable solutions, for large Structures, there are too many designs to evaluate. Even for this 3 by 3 plate example, where there are 9 Zones with 25 workable designs for each Zone. That's 259 possible designs. This sample size is too large to evaluate within a reasonable time frame.
To narrow the scope of designs HyperX uses an Annex Optimization approach. The Annex approach starts at the Zone with the thinnest Laminate and Sequences it with the closest neighboring Zones. For this area the lightest 'n' number of designs are stored. These stored designs are used in the next pass where more Zones are Annexed and Sequenced into the larger area. The number of designs stored (n) and the number of Zones that are Annexed for each pass are specified in the advanced section of the Sequencing Preferences (see below).
Scoring Algorithm
Each design is given a base score which is determined using the Structure weight and total number of Global Plies and Ply Cuts. The slider bar defines the relative weighting factor between the Structure weight and the Global Plies and Ply Cuts. Additional penalties are added to the score based on the user-defined optimization preferences such as improving interleaving and number of simultaneous drops and adds. If a preference of N/A is selected as an optimization preference, then no penalty is added to the base score based on that particular metric. The total score is used to display the top 20 Sequenced designs to the user.
Tip
To Improve Sequencing Results: Increase the number of requested designs on the assigned Design Property. This will provide more workable solutions per Zone so more compatible designs may be found; however, it will make the Sequencing passes run longer.
The Sequencing Form is used to generate Plies from Discrete Sizing results for Composites, either for Discrete Laminates or Laminate Families.
The form contains three main sections, listed top to bottom:
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Inputs - Fields on the left indicate the selected Structure and designs. Slider on the right specifies Sequencing priority, described below.
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Sequencing Results Summary - Provides weight and manufacturability data about each Sequencing solution produced.
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Zone Sequencing Results Table - Shows how every individual Ply covers each Zone. This table can be manually edited once populated with a Sequencing result.
Preferences
Sequence Using
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Ply Material ID (Default) - Sequences the Global Ply Stack assuming each Global Ply can only consist of a single Material.
Important
If two adjacent Laminates have Plies with different Material names, HyperX cannot Sequence them when determining the Global Ply Stack.
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Fabrication Process ID - Instead of using the Material name to determine if the Ply Materials are the same, HyperX will use the Fabrication Process ID, which is stored as a Material Property in the Orthotropic Material Form. This is useful if you want the Sequencing algorithm to treat two Materials as the same Ply during Global Ply Sequencing but you want to use unique Material Names and Properties during the analysis.
Laminate Sequencing Emphasis
For each Sequencing Emphasis, three choices are available: Low, Medium, and High. Default value = Medium.
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Reduce Global Ply Cuts - Set emphasis for disallowing Ply Cuts at the Ply Drop boundaries.
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Reduce Ply Drops - Set emphasis for disallowing Ply Drops at the Ply Drop boundaries.
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Reduce Simultaneous Drops & Adds - Set emphasis on disallowing Ply Drops and Ply Adds occurring together at a particular Ply Drop transition joint.
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Increase Outer Continuous Plies - Set emphasis on keeping Plies close to the surface continuous.
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Improve Interleaving - Set emphasis on interleaving Ply Drops (disallowing Plies to drop together at a particular Ply Drop transition joint).
Note
Interleaving Laminate sequencing is based on ESDU 91003.
Interleaving emphasis = N/A or Low, may produce designs as illustrated below.
Interleaving emphasis = Med or High, may produce designs as illustrated below.
Advanced
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Vary emphasis priorities... - Toggling this option on will cause all possible combinations of Laminate Sequencing Emphasis to be examined during Sequencing (Low, Med, High of each). This can generate better Sequencing results but will take longer to run.
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Requested Designs - This input controls the number of designs that are available on the blending form after blending is complete. 20 is the recommended value for this setting.
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Large Structure Solution Cutoff - Structures containing many Zones can take a considerable amount of time to Sequence. Consider reducing this number if the blending process takes too long. However, this will reduce the quality of the Sequenced solution. 20 is the recommended value for this setting.
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Zones Per Annex - The blending process is based on an annexing algorithm. Increasing this number will usually produce better blending results, but at the cost of run time. 2 is the recommended value for this setting.
Shuffling
Shuffling is used to move larger Plies to the IML and/or OML of the Laminate after Sequencing has been run. This helps move the Ply Drops/Adds to the interior of the Laminate.
Key points on Shuffling:
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Smaller Plies are combined to create larger Plies.
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Larger Plies are moved toward the IML and/or OML of the Laminate, based on your selection.
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The total Ply Count in each Zone is preserved during shuffling.
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The Stacking Sequence in each Zone is preserved as much as possible but will differ from the original result.
Important
Since Shuffling alters the Stacking Sequence, it is necessary to Analyze the Structure after the Plies have been committed, as the margins may be impacted by the Shuffling.
Before/after Shuffling example is shown below.
Tip
Sizing with Laminate Families is now the preferrable way to put larger Plies at the outer extremes of the Laminate.
Sequencing Results
The table at the top of the form displays the results of the Sequencing runs. The "Baseline" result is the result generated from the "Quick Sequencing" that is run automatically when the form first opens. The 2nd row contains results of Sequencing runs performed by clicking the Sequence button on the form.
Note
A Sequencing run typically produces multiple solutions which can be selected with the drop down in this row. The radio button in the table combined with the drop-down are used to specify which Sequencing solution will be used to generate Plies when the "Apply" button is clicked.
Weight
Displays the total Structure mass if the lightest optimum Laminates were used for each Zone in the Structure.
Laminate Producibility Metric 1, 2, and 3
Metrics related to the shape of Plies as well as the orientation of fibers relative to the boundaries. Lower scores are better. See examples below.
Plies
Total number of Global Plies in the Structure. This number should correspond to the Global Plies displayed in the Zone Sequencing results table.
Ply Cuts
The total number of Global Ply Cuts is quantified by summing the straight edge, end-of-ply boundaries for all Global Plies in the Structure. This metric directly corresponds to the number of actual Ply Cuts (fabric) or edges where the AFP tape head has to cut the fiber. This may be a more accurate way to score Sequenced designs, rather than using Ply Drops or Adds.
Individual Drops or Adds
Displays the sum of Plies either dropped or added at any transition joint in the assembly.
Simultaneous Drops & Adds
Is the total number of Plies, at Ply Drop transitions, that have both Ply Drops and Ply Adds occurring at the same location. As an example, a Structure has two Ply Drop transitions. The first Ply Drop has 7 Plies dropped, and 2 Plies added. The second Ply Drop has 5 Plies dropped and 1 Ply added. The number reported here = 3. The Ply-Drop joints where this occurs are noted with a 'X' in the D+A column of the Global Plies results tab.
Maximum Plies not Interleaved
Number of Plies in any angle direction that are dropping at the same time. Interleaving Ply Drops is considered good design practice, see Preferences, Improve Interleaving.
Tip
It is highly recommended to run Sizing with more than one Requested Design on the Design Property form. This gives HyperX more options to search through to find a viable, manufacturable solution.
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Select Zones to Sequence (must all be within the same Structure).
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Open the Sequencing Form from the Composites tab of the Ribbon. The form will automatically perform a "Quick Sequence" when opened to establish a baseline result. This baseline is based on keeping all Zones at their existing optimum Laminate attained from Sizing.
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Update the Sequencing priority slider bar setting if desired.
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Click the "Sequence" button.
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Review the resulting Plies in the table and make manual edits if desired.
Note
For Laminate Producibility Metrics 1, 2, and 3, LOWER values mean a MORE producible Structure.
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Click the "Apply" button to generate Plies corresponding to this solution.
Any panel concept with multiple facesheets, such as a sandwich, two-stack, or three-stack, requires an additional Sizing run after Sequencing is performed. This is necessary because the sequencing for one facesheet can potentially conflict with the sizing results of the other facesheet and result in negative margins if an intermediate sizing step is not performed.
Suggested workflow:
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Re-Analyze the structure to generate updated margins with the final Plies.
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Use the Ply Visualization features to view the generated Plies.