{"closest_prior_art":[{"name":"Effects of preload deficiency on fatigue demands of wind turbine tower bolts","overlap":"Reports large bolt-to-bolt preload variation in flange connections, identifies tightening interactions and torque uncertainty as causes, and models increased cyclic stress range and fatigue damage as preload falls.","remaining_difference":"Does not test whether acceptable global flange stiffness can conceal persistent circumferential tails, map contiguous outliers, or evaluate targeted passive-compliance cartridges while preserving the global response.","source_ids":["SRC1"]},{"name":"Disc-spring live loading of bolted flange joints","overlap":"Models disc springs placed in bolted flange joints to add flexibility and limit bolt-load loss caused by creep and relaxation.","remaining_difference":"Addresses general flange relaxation and washer sizing, not bolt-by-bolt indication, uncertainty-aware outlier sectors, targeted placement based on retained-preload maps, or a matched proof-cycle distributional test.","source_ids":["SRC2"]},{"name":"RCSC direct-tension-indicator installation and inspection practice","overlap":"Recognizes ASTM F959 direct tension indicators as approved bolt-tension-indicating devices and specifies component, installation, verification, and inspection requirements.","remaining_difference":"Primarily verifies achievement of required installation pretension; it does not establish the proposed repeated retained-force distribution, circumferential persistence rule, macro/micro crosswalk, or targeted compliant retrofit.","source_ids":["SRC3"]},{"name":"US4636120A stud/bolt load gauge","overlap":"Provides bolt-specific underload and overload indication using bolt elongation, observable gaps, and a Belleville spring washer, including monitoring whether proper axial load is maintained.","remaining_difference":"Its Belleville element is part of an indicator mounted on a gauge screw rather than a qualified series-compliance cartridge in the principal clamp-load path; it also lacks flange-ensemble mapping, global proof-response retention, contiguous-sector criteria, and matched intervention testing.","source_ids":["SRC4"]}],"contrastive_claim_falsifier":"The claim is falsified if the frozen coupon protocol does not reveal repeatable bolt-level tails or contiguous low-preload sectors beyond measurement uncertainty while global stiffness and alignment remain acceptable, if those tails do not correspond to local opening or cyclic-load consequences, or if a later matched cartridge trial fails to reduce the tails and opening without unacceptable flexibility, bearing stress, relaxation, fatigue, or clearance effects.","contrastive_claim_remaining":"For a flange whose global proof-load stiffness and alignment remain valid, synchronized bolt-by-bolt retained-preload measurements may reveal persistent circumferential tails associated with local opening; a reviewer-gated, targeted, displacement-set series disc-spring cartridge can reduce those tails and local opening relative to conventional washers without degrading the accepted global response or safety margins.","experiment_id":"eoa_inverse_innovation_exp13_second_slot_policy60_20260806","gates":{"adequate_source_search":{"rationale":"Four lanes covered the proposal directly, historical measurement terminology, recognized products/practices and standards, and combinations of indication, flange relaxation, fatigue, and disc-spring compliance. Four opened sources from three publisher families were retained, including primary research and an official specification. This is adequate only for a coarse screen.","source_ids":["SRC1","SRC2","SRC3","SRC4"],"status":"PASS"},"bounded_next_test":{"rationale":"The authorized first step is a single de-energized, unloaded representative coupon, with frozen membership, calibration, uncertainty, sectors, excursion rules, and approved proof limits. It makes a bounded decision about whether a separately authorized intervention trial is warranted and includes explicit stop and rollback conditions.","source_ids":["SRC1","SRC2","SRC3"],"status":"PASS"},"distinct_testable_claim":{"rationale":"The retained art separately establishes preload scatter and fatigue relevance, direct indication, and disc-spring mitigation. It does not disclose the full contrast: retain a valid global proof metric while testing persistent circumferential bolt tails and using those tails to gate a targeted compliant-cartridge trial.","source_ids":["SRC1","SRC2","SRC3","SRC4"],"status":"PASS"},"no_obvious_safety_or_authority_stop":{"rationale":"The first test forbids changes to in-service load-bearing fasteners, uses an unloaded approved coupon, preserves proof-strength and inspection requirements, and reserves preload bands, cartridge design, retensioning, retrofit, and release decisions to the structural review board. No obvious stop applies to the measurement-only step.","source_ids":["SRC2","SRC3"],"status":"PASS"},"supported_problem":{"rationale":"Research supports substantial torque-controlled preload scatter in flange bolts, increased fatigue demand from deficient preload, and flange bolt-load loss from relaxation. Direct-indication standards and measurement literature confirm that bolt tension warrants member-level verification. The specific coexistence of stable global indicators with persistent contiguous outlier arcs was not directly demonstrated by the retained sources, so support is partial but sufficient for a bounded test.","source_ids":["SRC1","SRC2","SRC3","SRC4"],"status":"PASS"}},"prior_art_disposition":"ADJACENT_PRIOR_ART","problem_evidence":{"finding":"The underlying problem is visible: individual flange-bolt preload can vary materially because of tightening interactions and torque uncertainty; preload deficiency increases fatigue demand, and relaxation can reduce flange clamp load and contribute to leakage. Existing direct-tension practices show that bolt-level force indication is established. The searched evidence does not directly verify the proposal's strongest conjunction—acceptable global stiffness and alignment coexisting with persistent circumferential preload clusters and local opening.","source_ids":["SRC1","SRC2","SRC3","SRC4"],"status":"PARTLY_SUPPORTED"},"research_id":"eoa_inverse_innovation_exp13_light_screen_20260806","schema_version":1,"screen_id":"E13P180","screen_survival":true,"search_lanes":{"component_combination":{"no_result_note":null,"queries":["bolt-by-bolt preload monitoring flange direct tension indicator Belleville washer preload loss","patent load indicating Belleville washer bolt preload flange","flange bolt preload indicator disc spring stack load indicating washer product"],"source_ids":["SRC2","SRC4"]},"direct_problem_and_intervention":{"no_result_note":null,"queries":["bolted flange stable global stiffness bolt preload scatter local opening fatigue research","non-uniform bolt preload distribution flange joint experimental local opening stiffness","Effects of preload deficiency on fatigue demands of wind turbine tower bolts"],"source_ids":["SRC1","SRC2"]},"products_practices_and_standards":{"no_result_note":null,"queries":["standard direct tension indicators structural bolts ASTM F959 preload","RCSC 2020 Specification structural joints DTI official PDF","Maxbolt mechanical load indicating fastener retained preload visual indicator first party"],"source_ids":["SRC3","SRC4"]},"synonyms_and_historical_terms":{"no_result_note":null,"queries":["disc spring washer bolted flange maintain preload settlement relaxation","stud bolt load gauge Belleville spring washer","Bolt Preload Measurements Using Ultrasonic Methods direct tension indicator"],"source_ids":["SRC2","SRC3","SRC4"]}},"sources":[{"claims_supported":["Torque-controlled flange bolts can exhibit substantial preload scatter because of tightening interactions and torque uncertainty.","Reduced preload in wind-turbine ring-flange bolts increases cyclic stress ranges and modeled fatigue damage."],"publisher":"Elsevier, Journal of Constructional Steel Research","source_id":"SRC1","source_type":"PRIMARY_RESEARCH","title":"Effects of preload deficiency on fatigue demands of wind turbine tower bolts","url":"https://www.sciencedirect.com/science/article/pii/S0143974X19311460"},{"claims_supported":["Creep and relaxation of gaskets, bolts, and flanges can reduce bolt load and contribute to flange leakage.","Disc springs are an established way to add joint flexibility and reduce bolt-load loss; the paper develops and validates a sizing model against finite-element results."],"publisher":"École de technologie supérieure research portal / Elsevier","source_id":"SRC2","source_type":"PRIMARY_RESEARCH","title":"The modelling of bolted flange joints used with disc springs and tube spacers to reduce relaxation","url":"https://pure.etsmtl.ca/fr/publications/the-modelling-of-bolted-flange-joints-used-with-disc-springs-and-/"},{"claims_supported":["ASTM F959 direct tension indicators are recognized components for structural high-strength bolting.","The specification defines installation, pre-installation verification, and inspection requirements and leaves alternative designs subject to Engineer of Record approval."],"publisher":"Research Council on Structural Connections","source_id":"SRC3","source_type":"OFFICIAL_STANDARD","title":"Specification for Structural Joints Using High-Strength Bolts, June 11, 2020","url":"https://boltcouncil.org/files/2020RCSCSpecification.pdf"},{"claims_supported":["A bolt-specific gauge can indicate underload, acceptable load, and overload through bolt elongation, observable gaps, and a Belleville spring washer.","Mechanical indication of whether proper axial load is maintained predates the proposal."],"publisher":"Google Patents / United States Patent record","source_id":"SRC4","source_type":"OTHER","title":"US4636120A — Stud/bolt load gauge","url":"https://patents.google.com/patent/US4636120"}],"world_novelty_boundary":"This bounded four-source screen found adjacent art for every principal component and an older bolt gauge combining mechanical load indication with a Belleville element. It did not find a direct disclosure of the complete flange-ensemble method: preserving a valid stable global proof response while using repeated bolt-level quantiles, persistence, and contiguous-sector mapping to gate targeted series-compliance cartridges and a distribution-aware repeat proof test. That search result cannot establish world novelty, patentability, market size, expert acceptance, or realized value."}