SATPC0034136 Tab 04 SOW.pdf

TDEA Point Design Welding SOW Summary The Thermoplastics Development for Exploration Applications (TDEA) project seeks to develop and demonstrate thermoplastic composite (TPC) welding for applications relevant to future NASA missions.

Toward this goal, TDEA has developed a series of structural test articles based on point designs to provide data on TPC welding for future NASA applications. The TDEA Thermoplastic Space Point Design (TSPD) is of particular interest here as a representative example where lunar surface welding of thermoplastic composites can be applied. In general, the approach is for NASA to design the relevant structures, manufacture and provide the structural elements to be joined, and evaluate the resulting joined assemblies. The vendor contributes by developing and applying ultrasonic welding to produced joined assemblies from the provided structural elements. The evaluation of the welded joints that NASA plans includes inspection and mechanical testing. The key findings from this study shall be published via NASA project reports, Tech Memorandum(s), or conference paper(s).

In this document, a requirement is identified by “shall,” a good practice by “should,” permission by “may” or “can,” expectation by “will,” and descriptive material by “is.”

Drawings have been produced for this effort. In the event of a discrepancy between this SOW and the drawings, the drawings take precedence for dimensions and tolerances, the SOW takes precedence for quantities.

Objective Develop and demonstrate ultrasonic welding for applications relevant to TDEA point design applications.

Phasing The work is divided into five blocks:

The blocks are independent work packages, though some are interrelationships exist. Block 1 shall be a standalone effort. Block 2 ‘baseline’ shall precede Block 4. And Block 4 shall precede Block 5. Block 2 dust variants can be performed in parallel with Block 4 and Block 5 work packages.

Tasks and requirements Test specimen configurations The welded specimens required for blocks 1-4 are listed in Tables 1-4, respectively. The specimen configurations are described further in the following four paragraphs. Each specimen shall be welded individually using a fixed welding station. For blocks 2-4, the quantities listed are the number of specimens welded and delivered to NASA for evaluation and test, which are intended as high-quality welds. The vendor shall specify the requirements for process development to produce these specimens.

Traceability between specimens and substrates shall be implemented and documented. NASA will provide a labeling scheme at a later date.

Temperature history measurements are required for two specimens of each condition identified in blocks 2-4 and will be used for process validation and model validation. Laser infra-red thermal spot measurements shall be acquired. The spot location should be a fixed point at the top surface of the top adherend located somewhere above the weld overlap region. The exact location will be chosen by the vendor to be practical and not interfere with the sonohead track. The location shall be consistent from sample to sample and reported to ±0.01 in with respect to either the sonohead or the sample edges.

The sample rate of the IR measurement should be >25Hz, with faster sampling rate preferred.

Thermocouples are required in blocks 2-4 at the locations shown by ‘x’ symbols in Figure 1 and Figure 3.

The thermocouples will be located directly on the specimens. Type ‘T’ thermocouples are suggested.

Thermocouple data shall be acquired at ≥ 25 Hz.

1. Effect of substrate manufacturing process

2. Effect of lunar dust simulant (TSPD dust coupons)

3. Effect of cold temperature and vacuum (TSPD chamber coupons)

4. TSPD sub-elements

5. TSPD representative unit cell (RUC)

Block 1 welds include the single lap shear (SLS) specimen configuration, detailed in drawings TDEA-2XX and TDEA-2YY. In the previous weldability study, specimen adherends were fabricated by hand layup and autoclave consolidation. These specimens investigate the effect of joining parts made by advanced fiber placement (AFP), and additive manufacturing (AM) processes. These processes will result in different surface finish, fiber volume content, and manufacturing defects compared with hand layup.

While the AM and AFP parts have nominally the same resin, the specific formulation of the resin used in the two parts may vary. The layups and thicknesses are consistent with the weldability study for comparison purposes. Block 1 welds work shall proceed with the number process development coupons identified in Table 1; no additional material will be available.

Table 1. Block 1 welds: Quantities of specimens to be welded (Effect of adherend manufacturing process).

Adherend 1 Adherend 2 Specimen count Material Thickness [in] Material Thickness [in] SLS Process

Dev

TC1225 AFP 0.086 TC1225 AFP 0.086 5 9

AM PEEK CF10 LS1 0.086 TC1200 AFP 0.086 5 9

Totals: 10 18

Figure 1. Single lap shear specimen dimensions (weld area shown as red dashed lines). Thermocouple measurement locations identified with ‘x’ symbols (block 2). Not to scale.

Block 2 welds include a series of SLS specimens welded with different levels of lunar dust simulant on the faying surface. These specimens are intended for relevance to TSPD application. Therefore, the material system is TC1225 T700/LM-PAEK producing an adherend thickness of 0.281 in and layup [452,903,-452,019]S. Note that the baseline condition is a clean (dust-free) condition to establish the nominal performance of welds for this configuration, which may vary from past work with thinner adherends. The last condition is a down selected dust contamination level, based on results obtained

Top

Side

1.0”

4.0”

Notional tool

0.38” TYP

0.12”

TC2

TC11

TC12

TC1x

TC2

1.12”

CL

1.0” from the low, medium, and high contamination levels. In support of block 2 specimen welds, NASA will provide material and evaluation support for up to 96 process development welds.

Table 2. Block 2 welds: Quantities of specimens to be welded (TSPD dust coupons).

Welding condition Specimen count Baseline 10 Dust contamination low 10 Dust contamination medium 10 Dust contamination high 10 Dust contamination selected level (fatigue) 15

Block 4 welds produce sub-element test articles where ‘L’ section structural elements are joined, as shown in Figure 3 with the dimensions tabulated in Table 5. The adherend material is TC1225 T700/LM- PAEK laid up by AFP and autoclave consolidated. The configuration includes welds on both flanges (need not join the fillet region). Block 4 builds on block 2 in that the adherend layups and thicknesses are similar. The vendor shall develop the required tooling and welding approach for these sub-element structural configurations. The vertical joint may be created with two separate, sequential welds on the two flanges. The weld setup shall be implemented such that the second weld does not degrade the first welds. Four thermocouples shall be located as shown by ‘x’ symbols in Figure 3. The specific thermocouple locations shall be proposed by the vendor and approved by NASA. The vendor shall cost a potential NASA request to include lunar dust simulant in the welds of up to 6 specimens and an alternative overlap length (single value) for 4 specimens. In support of block 4 specimen welds, NASA will provide material and evaluation support for up to 20 process development welds. The process development configuration will be single lap shear coupons with the same layups and as in the block 4 test specimens.

Table 3. Block 4 welds: Quantities of specimens to be welded (TSPD sub-elements).

Configuration Specimen count Vertical sub-element 16

Table 4. TSPD sub-element dimensions in inches.

Dimension Vertical sub-element Overlap length, 𝑙𝑙0 5.0 Weld length, 𝑙𝑙𝑤𝑤 4.4 Weld width, 𝑤𝑤𝑤𝑤 1.38

Figure 2. TSPD sub-element. Not to scale.

Block 5 introduces robotic enabled welding to produce one repeating unit cell (RUC) of the TSPD truss structure. The RUC is shown in Figure 4, and defined in TDEA-404. It includes 16 vertical joints (32 welds), 24 horizontal joints (24 welds), and 16 diagonal joints (16 welds). The adherend material is TC1225 T700/LM-PAEK laid up by AFP and autoclave consolidated. NASA will deliver all truss elements to be welded per the schedule below. The vendor shall develop a welding end-effector for an existing in-house robotic arm that is suitable for building an RUC. The robotic end-effector shall be integrated on the robotic arm, verified, and checked out. The vendor will design and fabricate fixturing to position the truss elements for welding. The vendor will use the robotic end-effector to create 72 welds resulting in a complete RUC structure per TDEA-404. The robotic operations and truss element positioning can include manual intervention (i.e. autonomous robotic operation is not required). In support of block 5 RUC welds, NASA will provide material and evaluation support for up to 60 process development welds. The process development configuration will be single lap shear coupons with 40 having layups equivalent to the diagonal joint and 20 having layups equivalent to the horizontal joint.

Drawings:

• TDEA-400, TSPD Joint Splice Plate

• TDEA-401, TSPD Diagonal Truss Member

• TDEA-402, TSPD Horizontal Truss Member

• TDEA-403, TSPD Vertical Truss Member

• TDEA-404, TSPD RUC Assembly

2.76” 2.

(0.324”)

(0.281”)

Vertical member

Joint splice plate

Figure 3. TSPD RUC concept.

Deliverables

1. Organize and participate in meetings with NASA

a. Kickoff meeting.

b. Bi-monthly status update meetings until all tasks are complete.

2. Develop and tune process for each weld configuration.

a. Provide process development plan with desired number of adherend to support weld process development and test matrix.

b. Process development data shall be captured and reported to NASA.

c. Report final welding parameters for each configuration.

3. Weld specimens described in blocks 1-5.

a. NASA shall provide concurrence on the process parameter selected from process development prior to commencing welding for test specimens.

b. Process data shall be reported for each weld as a function of time.

4. Report summarizing ultrasonic weld tooling design for block 4 and 5 welds.

5. Report summarizing ultrasonic welding end-effector design, integration, and check-out.

6. Ship welded articles to NASA.

7. Support test results interpretation and publication.

a. Review, discuss, and interpret results.

b. Co-author 1 technical report or conference paper.

Government Furnished Equipment Adherends shall be provided for each material and weld configuration described above. NASA will conduct NDE and mechanical tests as agreed in the process development plans. NASA may contract the adherend manufacture and machining. NASA will provide a mechanism, lunar simulant, and procedure for repeatable dust application.

Schedule Block Description Due date NASA ships process development & test article adherends 4/5/24 Report welding parameters based on process development

Weld process data provided Welded assemblies shipped 5/31/24 2 Process development plan (2.2a) 2/5/24 (2 weeks ARO) NASA ships process development & test article adherends 4/5/24 NASA provides dust application equipment, supplies, procedures 2/19/24 Report welding parameters based on process development (2.2c)

Weld process data provided (2.3b) 5/20/24 Welded assemblies shipped (2.6) 5/20/24 4 Report weld tooling design (4.4) 2/19/24 Process development plan (4.2a) 2/5/24 (2 weeks ARO)

NASA ships process development adherends 4/5/24 Report welding parameters based on process development (4.2c) 4/29/24 NASA delivers adherends for test articles 4/29/24 Weld process data provided (4.3b) 6/14/24 Welded assemblies shipped (4.6) 6/14/24

Report summarizing robotic welding checkout (5.5) 3/18/24 Process development plan (5.2a) 2/5/24 (2 weeks ARO) Report truss assembly fixturing and tooling design (5.4) 5/20/24

NASA ships process development adherends 4/5/24 Report welding parameters based on process development (5.2c) 5/27/24 NASA delivers elements and joint splice plates for RUC 5/27/24 Weld process data provided (5.3b) 8/5/24 Welded RUC assembly shipped (5.6) 8/5/24

Period of Performance 1/15/2024 – 8/30/2024

Travel / ODC Requirements None.

Technical POC Name / Code: Sandi Miller / GRC-LMC0 Title: Chemical Engineer Phone Number: 216-433-8489

CC on all communications:

Name / Code: Andrew Bergan / LARC-D309 Title: Senior Research Engineer Phone Number: 757-864-3744

Name / Code: Ken Segal / GSFC-5430, Heliospace Corporation Title: Senior Research Engineer Phone Number: 301-286-2895