Statement of Work

**Task Title:** Fabrication of fiber-placed composite cylinders

**Purpose, Objective or Background of Work to be Performed:**

Fiber-placed composite cylinders will be used to study the nonlinear
response, stability and failure of thin shell structures subjected to
combined loads. In addition, the cylinders will be used to determine a
process specific manufacturing signature.

**Description of the Work to be Performed:**

The contractor will fabricate ten fiber-placed circular cylinders is
requested. The cylinders will be constructed out of AS4/3502 slit tape.
Two laminate stacking sequences are required including a
\[+45/-45/0/90\]~s~, and \[+45/-45/0/90\]~2s~. The cylinders will be
trimmed to length such that the ends of the ends of the cylinders are
flat and parallel within +/- 0.030 inches. The cylinders should be
fabricated such that the end product is of high quality. More
specifically, gaps or overlaps between adjacent pieces of slit tape
should be held to a minimum and should be no wider than 0.03 inches. The
tape should be laid up on the tool to within +/- 1.0 degrees of the
desired ply orientation. Laminate delaminations are not acceptable.
Non-destructive evaluation of the cylinder construction will be
performed via an automated C-scanning technique on each shell to
determine their quality. Flaws greater than 0.1-inches in diameter are
not acceptable. The coordinate system must clearly be marked on each
cylinder specimen after fabrication is complete. The cylinders will be
configured as shown in Table 1 and manufacturing tolerances are
summarized in Table 2.

# Table 1. Cylinder configuration

  ----------------- ----------------- ----------------- ----------------------
  Specimen Name     Inner Diameter, D Length, L         Laminate

  MHCYL-02-01       18"               35"               \[+45/-45/0/90\]~s~

  MHCYL-02-02       18"               39"               \[+45/-45/0/90\]~s~

  MHCYL-02-03       18"               39"               \[+45/-45/0/90\]~s~

  MHCYL-02-04       18"               39"               \[+45/-45/0/90\]~s~

  MHCYL-02-05       18"               39"               \[+45/-45/0/90\]~s~

  MHCYL-02-06       18"               35"               \[+45/-45/0/90\]~2s~

  MHCYL-02-07       18"               39"               \[+45/-45/0/90\]~2s~

  MHCYL-02-08       18"               39"               \[+45/-45/0/90\]~2s~

  MHCYL-02-09       18"               39"               \[+45/-45/0/90\]~2s~

  MHCYL-02-10       18"               39"               \[+45/-45/0/90\]~2s~
  ----------------- ----------------- ----------------- ----------------------

# 

# Table 2. Manufacturing Tolerances

  ----------------------------------------- -----------------------------
  Cylinder-end Flatness                     +/- 0.03"

  Ply gaps and overlaps                     +/- 0.03"

  Ply orientation                           +/- 1^o^

  NDE defect size                           0.1"

  Mandrel Diameter                          +/-0.005"
  ----------------------------------------- -----------------------------

A typical cylinder configuration with dimensions and coordinate system
is shown in Figure 1.

![](media/image1.wmf){width="0.12013888888888889in"
height="0.12013888888888889in"}

**Figure 1. Cylinder configuration.**

In addition, four flat plate specimens will be fabricated with the
intention of using them for coupon testing to develop material property
data. The flat plate specimens will each be 14" by 14" square. One plate
will be a 48-ply unidirectional laminate, two plates will be an 8-ply
unidirectional laminates, and the final plate will be an 8-ply angle-ply
laminate. The coordinate system of the plates must clearly be marked
after fabrication. The plate specimens are summarized in Table 3.

# Table 3. Flat Panel Specimens

  ----------------- ----------------- ----------------- -----------------
  Specimen Name     Width, W          Length, L         Laminate

  MHP-02-01         14"               14"               0~48~

  MHP-02-02         14"               14"               0~8~

  MHP-02-03         14"               14"               0~8~

  MHP-02-04         14"               14"               \[(+45/-45)
                                                        ~2~\]~s~
  ----------------- ----------------- ----------------- -----------------

The fabricators will be responsible for procuring all required material
and hardware necessary to fabricate the cylinders including the AS4/3502
slit tape, fixtures, shipping containers, etc.

Three acid digest tests from representative tag end samples from each
cylinder will be conducted to determine laminate void content, and resin
and fiber content. Information about fiber and resin lots, batches, etc
should be furnished upon completion of the task.

[Deliverables]{.underline}:

-   Ten fiber-placed composite cylinders shall be delivered to NASA-LaRC
    (See Table 1)

-   Four fiber-placed flat panel specimens suitable for testing shall be
    delivered to NASA-LaRC

-   (See Table 3)

-   Monthly progress reports of work accomplished during each one-month
    period of the contract performance.

-   A final report that documents all work conducted under this task to
    be submitted and should include detailed results from the
    non-destructive evaluation of the cylinders as well as the results
    from acid digest tests indicating laminate void content and resin
    and fiber volume content.

[Schedule]{.underline}:

-   The fabrication of 10 cylinder specimens and four flat panel
    specimens shall be completed within the first 6 months of the task.

-   Deliver all monthly reports to LaRC within the first 7 days
    following the period of performance being reported upon.

-   Deliver the final report to LaRC within 30 days after the end of the
    period of performance for the task.

**Period of Performance:**

Expected Completion Date: 6 months after the award of the order.