6913G620Q300041 Statement of Work.docx

Department of Transportation Volpe National Transportation Systems Center Laboratory Material and Component Level Tests to Obtain General and Mechanical Properties of Fiber-Reinforced Plastic Specimens from Cargo Tank Motor Vehicle Manufacturers

Statement of Work

Background The Volpe National Transportation Systems Center (Volpe) is currently conducting a study to establish experimental testing procedures and develop a finite element analysis (FEA) framework that can be used to evaluate the performance and determine the specifications of cargo tank motor vehicles (CTMV) made with fiber-reinforced plastic (FRP) materials. Because the Hazardous Materials Regulations (HMR) do not address the specific performance requirements for FRP CTMVs, the U.S. Department of Transportation’s Pipeline and Hazardous Materials Safety Administration (PHMSA) has been issuing special permits with renewable terms for commercial companies to manufacture, sell and use FRP cargo tanks for highway HM transportation. With increasing omnipresence and acceptance of the FRP CTMVs as an industrial standard for transporting corrosive HM, there have been calls to include FRP CTMV performance requirements in the HMR, so as to not only maximize the FRP CTMVs’ safety potential but also relieve both the PHMSA and the industrial stakeholders of the burden of the special permit application, authorization and renewal processes. The ultimate goal of the Volpe study is to provide performance data and technical parameters for PHMSA’s consideration in possible rulemaking on FRP CTMVs. The first phase of the study being conducted by Volpe will include obtaining FRP specimens from commercial FRP cargo tank packaging manufacturers, conducting material and component level testing on the FRP specimens, and developing FE model parameters using the material and component level test data. A second phase of the study will include developing full scale FE models of FRP CTMVs and conducting numerical simulations to evaluate their performance.

Volpe is in process of obtaining specimens from FRP CTMV manufacturers that are consistent in material constituents and composite properties with those employed in the manufacture of the FRP cargo tanks. Specified hereunder, this Statement of Work solicits laboratory testing services to obtain general and mechanical properties pertaining to these specimens.

Scope of Work Upon reviewing the American Society for Testing and Materials’ (ASTM) FRP test standards, American Society of Mechanical Engineers’ (ASME) Boiler and Pressure Vessel Code (BPVC) and HMR Part 178, Subpart J, among other documents, Volpe has defined the requirements for the material and component level tests to be conducted on FRP materials, core materials and/or sandwich structures used in manufacturing the FRP CTMVs. FRP cargo tank structures are typically two elliptical heads connected by a cylindrical shell. There are two common constructions of the tank walls: a single FRP wall structure, or two FRP face materials sandwiching a core material. For a single wall structure, only the FRP wall material will be obtained and tested. For a sandwich wall structure, three material/structure types will be obtained and tested: FRP material, core material and sandwich structure. The core materials and majority of the sandwich specimens are being tested under a separate contract. The FRP and sandwich specimens are expected to be flat panels manufactured using potentially one of a variety of methods, such as a hand layup, vacuum infusion, autoclave, filament winding, or similar method depending on the specific process employed at the FRP cargo tank manufacturing plant. For the purpose of comparing flat versus curved specimen behaviours, curved specimens manufactured and/or cut out from actual vessels may be provided for a small set of selected tests to be conducted on these specimens.

This Statement of Work solicits engineering testing services to obtain general and mechanical properties. The general properties include constituent content, density, thickness, etc. The mechanical properties include anisotropic elasticity, anisotropic strengths, impact strength and toughness, fatigue performance, etc. The material parameters obtained in these tests are crucial for the FEA and performance evaluation of full scale FRP CTMVs, to be conducted in Phase II of the Volpe study.

The test matrix is defined solely in terms of ASTM test standards. Table 1 summarizes the expected type and number of materials/structures to be obtained from the manufacturers and tested. Table 1 specifies the “Required” numbers of materials for each material type to be obtained and tested in this Statement of Work. Depending on the availability of the materials to be supplied by the manufacturers, additional optional tests may be ordered by Volpe not to exceed the numbers specified under “Maximum Optional” numbers of materials. The total numbers of materials to be tested are not expected to exceed the “Maximum Total” numbers of materials in Table 1. The expectation is that manufacturer specimens will become available for testing at different times and the intention is that testing will be conducted as materials become available. Table 2 shows the ASTM standard tests referenced in this Statement of Work, along with a list of main properties to be obtained in each test, required sampling/repeat test numbers and test parameters expected to be provided by Volpe. As identified above, the material and component level test data will be used by Volpe to develop FE model parameters. To support development of the FE models Volpe will also require the contractor to provide additional test information beyond what may typically be required. Upon Volpe request the contractor will provide additional information on the actual test equipment, coupon geometry, fixture geometry, applied loads, as well as other test specific information needed to support development of the FE models. Table 2 shows additional test specific information that is expected to be needed for the FE models.

Table 1. Materials to be Tested.

The FRP specimens are expected to include both glass and carbon FRPs. In addition to the FRP materials from flat specimens (with flatness being required by most of the referenced ASTM test standards), a small number of sandwich structures and curved FRP specimens are expected to be provided for testing. The curved FRP specimens will be excised from existing FRP cargo tanks during manufacture, or will be fabricated to a similar degree of curvature as would be found in the shell of a typical FRP cargo tank. The curved FRP specimens are expected to have a curvature in the hoop direction. For the curved specimens the contractor shall conduct only the ASTM D3171 content test, the ASTM D3039/D3039M tensile test in the axial direction only (modified to accommodate the curvature in the hoop direction, see Test Reference No. 3B in Table 2) and ASTM D790 (modified to accommodate the curvature in the hoop direction, see Test Reference No. 6B in Table 2). Some of the curved specimens are expected to be supplied as sandwich structures, in which case, prior to cutting out the test coupons from these specimens, the contractor shall separate the FRPs from the cores in the sandwich structures and clean up the FRP specimens for further test preparation. For ASTM D3171 (Tests 1A & 1B) the laboratory should provide not to exceed unit pricing following the equilibrium drying requirements per ASTM D5229 (as referenced by ASTM D3171) for a not to exceed period of 7 days to reach equilibrium per the standard. For ASTM D3039/D3039M the test will be performed to be able to obtain failure at a maximum test load of 25,000 lbf. If necessary due to test equipment limitations, the standard coupon size cut from the specimen is to be adjusted within the requirements of the standard and as needed to be able to obtain failure at a test load of 25,000 lbf. The contractor should run a trial test to determine the appropriate coupon size needed to obtain failure at 25,000 lbf and whether tabs (untabbed, using emery paper, etc.) are necessary to ensure failure occurs outside of the grip sections.

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Table 2. ASTM Test Standards and Main Properties to be Obtained.

· Geometry of tabs if used

· Geometry of curved coupon

· Geometry of tabs if used

· Geometry of curved coupon

Typical in-plane dimensions of the specimen panels from which coupons will be excised are expected to be on the order of 18 x18 inch2 and 24x24 inch2 but can vary by manufacturer. The specimen panels will have various thicknesses conforming to manufacturer specifications. Typical nominal thicknesses are expected to include 0.25, 0.3125, 0.375 and 0.5 inches for the FRPs, and up to 1.25 inches for the sandwich structures. However, deviations from the nominal thicknesses are expected. Owing to variations in the manufacturing process, some FRP specimens are expected to be more than 0.6 inches thick and some sandwich structures are expected to be up to 1.5 inches thick. In cases that the specimen thickness exceeds the recommended range specified in a specific test standard, the contractor shall consult with Volpe and if feasible, propose modifications to the tests to accommodate the thicker specimens. One FRP specimen panel from each manufacturer is expected to have a nominal thickness of 0.75 inches, as required by the ASTM D5379/D5379M shear test standard (Test Reference No. 4) for the tests to be conducted in the two thickness related directions. All specimen panels are expected to meet the flatness requirements of specific ASTM test standards, with the exception of Test Reference Nos. 1B, 3B and 6B as discussed above.

The scope of work includes: receive, examine and document the specimen panels shipped from the manufacturers or Volpe; cut out the test coupons from the specimen panels and prepare/treat/condition them according to ASTM standard test specifications and any specific instructions provided in this Statement of Work; conduct the tests in the required repeat numbers (as specified by the ASTM standard); provide QA/QC and accuracy verification of the test data; conduct simple statistical analyses and report test data according to the test standard and/or specific Volpe instructions (as defined in this Statement of Work), including providing pre- and post-test photographic documentations of the specimens; ship unused and lightly used specimen panels back to Volpe, and ship back or archive post-test coupons/specimens; and conduct regular project progress meetings and report test data to Volpe as soon as they are obtained and QA/QC verified.

Requirements The contractor shall have expertise in the following areas:

· Professionally accredited testing capabilities of the ASTM standard tests listed in Table 1;

· In-house facility and equipment to conduct the testing work;

· Prior experiences with conducting the ASTM standard tests listed in Table 1;

· Ability and experience with advanced edge-cutting techniques in test coupon preparation;

· Ability to statistically analyze the test data and provide reports that meet ASTM standard and Volpe requirements.

The contractor shall provide adequate labor to enable timely completion of the project.

The contractor shall seek Volpe approval to substitute an equivalent test for any test in Table 1 with reasonable justifications such as reduced cost, more accurate result, more comprehensive test data, etc.

Period of Performance Period of performance is from date of award through March 31, 2021.

Place of Performance The work shall be done at the contractor’s location.

Work Requirements Definition of Test and Report Procedures. For each test to be conducted on a required material or an optional material (if the option is elected to be exercised), the contractor shall conduct four stages of the test and report procedures defined as follows.

Test coupon preparation. The contractor shall cut out the test coupons from the specimen panels and prepare/treat/condition the coupons according to the ASTM standard test specifications and any specific instructions provided in this Statement of Work. Prior to cutting the test coupons from the specimen panels, the contractor shall develop a cut-out plan to maximize the usage of each specimen panel. The cut-out plans for each panel shall be provided to Volpe for review before cutting commences on that specific panel. The edges of the test coupons shall be cut smooth to avoid introducing stress concentrations. Edge smoothness equivalent to or better than that obtained by the water jet cutting method is required for the FRP test coupons.

There have been concerns that damaged edges can particularly lead to lower hoop properties measured in the ASTM D3039 test. To eliminate or minimize this effect, when preparing coupons for testing according to the ASTM D3039 test standard in an FRP material’s hoop direction, the contractor shall follow the procedures described in the attachment (to this Statement of Work) titled “Instructions on Cutting Coupons from Flat FRP Specimen Panels for ASTM D3039 Tensile Test in the Transverse or Hoop Direction” (or similar ones eliminating/minimizing the edge damage, as verified with and approved by Volpe).

Performance of tests. The contractor shall conduct the tests specified in the test matrix following the ASTM test standard specifications and any modifications identified within this Statement of Work and/or subsequently agreed to by Volpe. The tests shall be conducted for the specified material/structure type in the required repeat number of tests in each specified material orientation, as defined in the test matrices hereafter. If needed and as material panel size permits, the contractor may prepare extra coupons and conduct trial tests on the extra coupons to establish procedure, parameter range, etc., prior to conducting actual required tests. For the fatigue tests, the contractor shall consult with Volpe to verify number of load levels, number of repeat tests, frequency and number of loading cycles, criteria to terminate the tests, etc. Substitution for any test in the test matrices shall be subjected to Volpe approval. The contractor shall plan to accommodate Volpe requests and arrange for Volpe and/or PHMSA engineers to visit the testing facility and observe the test procedures.

Unless otherwise agreed to by Volpe, the contractor shall observe the following priority order of tests to be conducted:

· Tensile/shear tests before bending tests;

· Tensile tests before tension-tension fatigue tests;

· Fatigue tests concurrent with non-fatigue tests;

· Static before indentation/impact tests; and

· FRP tests before sandwich structure tests.

Application of QA/QC measures. The contractor shall have an established plan for quality assurance (QA) and quality control (QC) and have it executed for the test procedure, test outcome and verification of data accuracy in this project. The contractor shall provide Volpe with a copy of the QA/QC plan as part of the Contractor’s proposal.

Report of test data. As identified above, the general and mechanical properties test data generated under this SOW will be used by Volpe in developing component level and full scale FE models of FRP CTMVs and conducting numerical simulations to evaluate their performance. It is to be able to support development of FE models that Volpe requires additional test information beyond what may typically be required under a test standard. The contractor shall perform statistical analyses of the test data, such as calculating the average and standard deviation of a given parameter obtained in a test, as required by the test standards. The contractor shall report the test data according to the test standard and specific Volpe instructions as outlined within this Statement of Work. Force-displacement and stress-strain data generated in any test shall be included in the test report and data delivery, in addition to other test data specified by the test standards. For instance, the force-displacement data obtained in ASTM D790 shall be reported in addition to the other data specified by the test standard. The contractor shall deliver the test reports and test data electronically, unless requested otherwise by Volpe. Raw and processed data from each repeat test shall be delivered to Volpe in the electronic Excel file format. Electronic comma/tab delimited text files that can be easily converted to Excel worksheets will also be acceptable. Images only of data sheets/data curves will not be acceptable. The contractor shall promptly deliver the test data to Volpe once the data are obtained and QA/QC verified, whereas the test reports shall be delivered by the deliverable due dates.

Photographs shall be taken of pre-test coupons including one mounted on the test fixture for each test. Photographs shall be taken of each post-test coupon clearly showing salient post-test features including deformation pattern, damage pattern, failure mode, etc. The contractor shall provide Volpe with electronic copies of the photos with clear and distinct identifications.

Tasks. The work is broken down into the following tasks.

List of subtasks:

Table 3. Test Matrix for FRP Materials

Required No. Tests (units ) Max. No. Optional Tests (units)

* For coupons from curved FRP specimens. See descriptions of curved FRP specimens in “Scope of Work” under Table 1.

Task 3. Conduct tests on sandwich structures. Under Subtask 3.1 the contractor shall conduct the “Required No. Tests” listed in Table 4. Volpe may elect for the contractor to conduct additional optional tests (Subtask 3.2) up to the number specified under “Maximum Optional Tests” in Table 4 for each test reference number. The contractor shall follow the procedures outlined in “Definition of Test and Report Procedures” above for each test.

List of subtasks:

Table 4. Test Matrix for Sandwich Structures

(included as part of 1 unit test)

To be Tested No. of Tests (units) to be Performed

Required No. Tests (units ) Maximum Optional Tests (units)

Task 4. Following the completion of all tests the contractor shall consult with Volpe on the plan and method to return and/or archive the unused, lightly used and post-test coupons/specimens. At the end of the project, the contractor shall inspect the remaining specimen panels, collect unused specimens and lightly used ones that can still be of future use, and ship them back to Volpe upon Volpe’s request.

Task 5. Project Management. The contractor shall provide Volpe with a copy of the QA/QC plan at the initiation of the project. Once test specimens are received, inspected and documented for each manufacturer, the contractor shall contact Volpe via an initial teleconference or in-person meeting to report the specimen conditions, verify tests and order of tests to be performed, confirm test reporting requirements, determine/verify specific test parameters required by the test standards, deliverable due dates, etc. As the project progresses, this task shall include regular communications (including teleconferences) with Volpe and project management.

Schedule and Deliverables List of schedule and deliverables:

0201 – 0213 (optional)

(optional) 3.2 (optional)

*Deliverables shall be electronically delivered to Technical Point of Contact.

Technical Point of Contact:

Mark Raney

(617) 494-2377 Email: Mark.Raney@dot.gov

Attachment to Statement of Work

INSTRUCTIONS ON CUTTING COUPONS FROM FLAT FRP SPECIMEN PANELS FOR ASTM D3039 TENSILE TEST IN THE TRANSVERSE OR HOOP DIRECTION

Specimen Geometry

1. Rectangular coupons. Refer to Figure 1 for nomenclature. Faces flat and parallel to < 0.08mm. Edges flat and parallel to <0.08mm.

2. Finished specimen width of 25mm meets the requirements of ASTM D3039 (2017).

3. Specimen length determined as per the standards. Specimen length is a function of the gauge length and the grip length (which can vary according to the testing machine).

Figure 1: Specimen nomenclature. For transverse (hoop) testing, fibres are aligned width-wise.

4. Caul plates should be used to ensure high quality finish of specimen faces. The caul plates should be free from scratches and marks which could induce defects in the specimen’s faces.

5. Specimen cutting is best conducted with abrasive machining (milling, rotatory sawing, etc.) with diamond tooling. A representative cutting plan is shown in Figure 2.

a. An assessment of induced damage should be made. Particular attention should be focused on the exit face of the cutting path to ensure there is no (or highly localized) delamination damage. Cutting parameters may need to be adjusted until this can be achieved.

b. Specimen widths should be cut oversized to allow for edge finishing. An oversize of +5mm should suffice in most cases.

c. Water jet cutting may be substituted. The cutting kerf may vary between cutting methods and should be accounted for when developing the cutting plan for the panel. Water jet piercing operations induce significant damage and should be avoided on the test panel.

6. Specimen edges must be finished as well as practically possible. Specimens may be stacked and clamped face-to-face in a block to minimize the number of finishing operations. The following treatments are required:

a. Surface grinding to +0.3-0.5mm on both opposite edges. Grinding parameters vary but material removal rates should be kept low enough to not induce damage.

b. Polishing with 800, 1200 grit wet and dry paper to required dimension.

c. Target surface roughness <32 microinches Ra, approximately 1 micron. (Ra definition: http://www.rubert.co.uk/faqs/roughness-parameters/)

7. Specimen polishing may not be practical for all applications, but methods to mitigate edge damage should be made.

8. Finishing is not required for ends and these faces are unloaded during testing.

Figure 2: Representative cutting plan.

Tabbing and Gripping

1. The standards are open about the lack of consistency in gripping and tabbing. According to ASTM D3039:

“Design of mechanical test coupons, especially those using end tabs, remains to a large extent an art rather than a science, with no industry consensus on how to approach the engineering of the gripping interface. Each major composite testing laboratory has developed gripping methods for the specific material systems and environments commonly encountered within that laboratory. Comparison of these methods shows them to differ widely, making it extremely difficult to recommend a universally useful approach or set of approaches.”

2. Use untabbed coupons for transverse (hoop) testing. Use Surfalloy (TM) grips with 2-3 layers of emery paper between the grip and the specimen. The emery paper extends beyond the grip region to ensure a smooth load transition (Figure 3).

Figure 3: Grip configuration showing use of emery paper.

Instrumentation

1. Use ASTM D3039 and ISO527-5 recommended 3 strain-gauge configuration as shown in Figure 4 (ISO527 version) to enable assessment of specimen bending during the test. Any specimen bending >3% results in a failed test, so flatness is crucial. If a 3 strain-gauge configuration cannot be accommodated due to the size strain gauges available, the contractor is to use a back-to-back configuration to assess the bending.

Figure 4: Specimen strain gauge locations (ISO527).

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