# US 11,298,754 B1 · Mode I fracture testing fixture > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,298,754 B1 - Document ID: US11298754B1 - Status: Granted - Kind: B1 - Application number: 16/878,731 - Filed: 2020-05-20 - Granted: 2022-04-12 - Earliest claimed: 2020-05-20 - Assignees: National Technology & Engineering Solutions of Sandia, LLC - Applicants: National Technology & Engineering Solutions of Sandia, LLC - Inventors: Timothy Briggs - Web page: https://patentgrep.com/patent/US11298754B1 ## CPC - B23B 47/28: Drill jigs for workpieces (equipment for setting or guiding the drill B23B49/00) - B23B 47/288: {involving dowelling} - G01M 5/0033: {by determining damage, crack or wear} - G01N 3/08: by applying steady tensile or compressive forces (G01N3/28 takes precedence) - G01N 3/24: by applying steady shearing forces (G01N3/26, G01N3/28 take precedence) - B23B 2247/12: Drilling jigs with means to affix the jig to the workpiece - G01N 2203/0091: Peeling or tearing - G01N 2203/04: Chucks, fixtures, jaws, holders or anvils - B23B: TURNING; BORING (arrangements for copying or controlling B23Q) - G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract An apparatus and method for preparing Double Cantilever Beam (DCB) specimens are disclosed as an apparatus and method for conducting Mode I fracture resistance testing using the DCB specimens. In a first embodiment, a drill jig is used to locate the DCB specimen and guide a drilling process during creation of at least one through-hole in the DCB specimen. The drilling process may employ a traditional drill and drill bit, a laser drill, or a water jet. In another embodiment, a set of rotating pin blocks, each with a full-round or a half-round specimen pin at one end and a hanger full-round pin at the other end, engage the DCB specimen and facilitate the internal application of a fracturing load to the DCB specimen for the Mode I fracture resistance test. The present invention may significantly reduce the time and materials needed to prepare and test a DCB specimen. ## Claims ### Claim 1 A method for conducting a Double Cantilever Beam (DCB) test comprising the steps of: providing upper and lower pin block hangers; providing at least two rotating pin blocks, each of the at least two rotating pin blocks including a specimen half-round pin and a hanger full-round pin, each specimen half-round pin substantially parallel to a corresponding hanger full-round pin; providing a DCB specimen having one hole therethrough; rotationally mechanically coupling each hanger full-round pin of each of the at least two rotating pin blocks to a corresponding one of the upper and lower pin block hangers; rotationally mechanically coupling each specimen half-round pin of each of the at least two rotating pin blocks to the DCB specimen via the one hole in the DCB specimen; applying a fracturing load to the DCB specimen via the at least two rotating pin blocks and the upper and lower pin block hangers; recording the applied fracturing load as a function of time; recording an interlaminar delamination crack length as a function of time; and calculating the strain energy release rate of the DCB specimen based upon the recorded applied fracturing load and the recorded interlaminar delamination crack length. ### Claim 2 (depends on 1) The method of claim 1, further comprising the step of performing fractography. ### Claim 3 (depends on 1) The method of claim 1, wherein a flat surface of a specimen half-round pin of a first of the at least two rotating pin blocks is adapted to face a corresponding flat surface of an opposing specimen half-round pin of a second of the at least two rotating pin blocks. ### Claim 4 (depends on 1) The method of claim 1, wherein the at least two rotating pin blocks includes four rotating pin blocks; wherein an end of a specimen half-round pin or a hanger full-round pin of each of the four rotating pin blocks includes a portion of an interlocking feature; and wherein the portion of the interlocking feature of a first of the four rotating pin blocks is adapted to fixedly mechanical couple with the portion of the interlocking feature of a second of the four rotating pin blocks. ### Claim 5 (depends on 4) The method of claim 4, wherein the interlocking feature includes one of a rod and corresponding recess, a tab and corresponding slot, and meshing teeth. ### Claim 6 (depends on 1) The method of claim 1, wherein each specimen half-round pin and each hanger full-round pin of each of the at least two rotating pin blocks is fixedly or removably attached to a body of a corresponding one of the at least two rotating pin blocks. ### Claim 7 (depends on 1) The method of claim 1, further comprising the step of preparing the DCB specimen, the step of preparing the DCB specimen including the steps of: locating the DCB specimen within a drill jig; aligning a drill with the DCB specimen at a predetermined position, the predetermined position being aligned with a laminar interface between first and second joined adherend layers that form the DCB specimen; drilling the one hole through the DCB specimen at the predetermined position.