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Stress intensity factor solutions for cracks in threaded fasteners

Description: Nondimensional stress intensity factor (K) solutions for continuous circumferential cracks in threaded fasteners were calculated using finite element methods that determined the energy release rate during virtual crack extension. Assumed loading conditions included both remote tension and nut loading, whereby the effects of applying the load to the thread flank were considered. In addition, K solutions were developed for axisymmetric surface cracks in notched and smooth round bars. Results showed that the stress concentration of a thread causes a considerable increase in K for shallow cracks, but has much less effect for longer cracks. In the latter case, values of K can be accurately estimated from K solutions for axisymmetric cracks in smooth round bars. Nut loading increased K by about 50% for shallow cracks, but this effect became negligible at crack depth-to-minor diameter ratios (a/d) greater than 0.2. An evaluation of thread root acuity effects showed that root radius has no effect on K when the crack depth exceeds 2% of the minor diameter. Closed-form K solutions were developed for both remote-loading and nut-loading conditions and for a wide range of thread root radii. The K solutions obtained in this study were compared with available literature solutions for threaded fasteners as well as notched and smooth round bars.
Date: February 1, 1999
Creator: Oster, D.M. & Mills, W.J.
Partner: UNT Libraries Government Documents Department

Metallurgical examination of gun barrel screws

Description: The examination was conducted to determine the extent of degradation that had occurred after a series of firings; these screws prevent live rounds of ammunition from being loaded into the firing chamber. One concern is that if the screw tip fails and a live round is accidentally loaded into the chamber, a live round could be fired. Another concern is that if the blunt end of the screw begins to degrade by cracking, pieces could become small projectiles during firing. All screws used in firing 100 rounds or more exhibited some degree degradation, which progressively worsened as the number of rounds fired increased. (SEM, metallography, x-ray analysis, and microhardness were used.) Presence of cracks in these screws after 100 fired rounds is a serious concern that warrants the discontinued use of these screws. The screw could be improved by selecting an alloy more resistant to thermal and chemical degradation.
Date: June 1, 1996
Creator: Bird, E.L. & Clift, T.L.
Partner: UNT Libraries Government Documents Department

Test plan and report for maxi-drill model 3030 foot-clamp

Description: This test plan and report defines the testing performed to determine whether the MAXIDRILL Model 3030 Footclamp meets the needs of RMCS operations. This document reports the outcome of the test pesformed. The new footclamp will enhance the safety of RMCS operations.
Date: June 24, 1999
Creator: Boger, R. M.
Partner: UNT Libraries Government Documents Department

Samus Counter Lifting Fixture

Description: A lifting fixture has been designed to handle the Samus counters. These counters are being removed from the D-zero area and will be transported off site for further use at another facility. This fixture is designed specifically for this particular application and will be transferred along with the counters. The future use of these counters may entail installation at a facility without access to a crane and therefore a lift fixture suitable for both crane and/or fork lift usage has been created The counters weigh approximately 3000 lbs. and have threaded rods extended through the counter at the top comers for lifting. When these counters were first handled/installed these rods were used in conjunction with appropriate slings and handled by crane. The rods are secured with nuts tightened against the face of the counter. The rod thread is M16 x 2({approx}.625-inch dia.) and extends 2-inch (on average) from the face of the counter. It is this cantilevered rod that the lift fixture engages with 'C' style plates at the four top comers. The strongback portion of the lift fixture is a steel rectangular tube 8-inch (vertical) x 4-inch x .25-inch wall, 130-inch long. 1.5-inch square bars are welded perpendicular to the long axis of the rectangular tube at the appropriate lift points and the 'C' plates are fastened to these bars with 3/4-10 high strength bolts -grade 8. Two short channel sections are positioned-welded-to the bottom of the rectangular tube on 40 feet centers, which are used as locators for fork lift tines. On the top are lifting eyes for sling/crane usage and are rated at 3500 lbs. safe working load each - vertical lift only.
Date: May 27, 1998
Creator: Stredde, H.
Partner: UNT Libraries Government Documents Department


Description: This calculation applies to the Constructor's design of the proposed jacking bracket for the W6 x 20 steel set. The specific features of the jacking bracket evaluated in this analysis are the shear on the bracket bolts, and the effects of the applied moment on the W6 x 20 steel set beam segment.
Date: March 28, 1996
Creator: Stine, Marvin D.
Partner: UNT Libraries Government Documents Department


Description: This paper provides a brief history of the U.S. Type B 6M specification container, its introduction into U.S. Code of federal regulations and its scheduled elimination three decades later. The paper also presents development, testing and deployment by the Department of Energy (DOE) of an enhanced drum closure called the 'Blanton Clamshell' (patent pending) that was designed to replace the standard open-head C-ring closure for the 55- and 85-gallon drums described in the 6M specification to extend their safe use. Nuclear Filter Technology has the Exclusive License for Clamshell production. Drum packages utilizing the standard C-ring closure have been a main-stay for over a half of a century in the national and international nuclear industry for shipping radioactive materials and will remain so in the foreseeable future. Drum package use in the U.S. increased heavily in the 1950's with development of the Weapons Complex and subsequently the commercial nuclear reactor industry.
Date: October 18, 2007
Creator: Blanton, P
Partner: UNT Libraries Government Documents Department

EXAMINATION OF SHIPPING PACKAGES 9975-01818, 9975-01903 AND 9975-02287

Description: Three 9975 shipping packages were examined to investigate the non-conforming condition of an axial air gap greater than 1 inch. This condition typically indicates the presence of excess moisture in the fiberboard overpack, and may be accompanied by degradation in the fiberboard properties. The package with the largest axial air gap (9975-01818, with an air gap of 1.437 inches) was found to contain significant excess moisture, and the lower fiberboard assembly was covered with mold and was significantly degraded in strength. This condition is very similar to that observed previously in package 9975-01819. Both packages (-1818 and -1819) appear to contain a similar amount of excess moisture, which was previously estimated for 9975-01819 as {approx}2.5 liters. The condition of 9975-01818 was also evidenced by several rust spots along the bottom chime of the drum, although no significant rust was noted on the closure bolts. Packages 9975-01903 and 9975-02287 were also examined. The axial air gap in these two packages was less than in 9975-01818, but still exceeded 1 inch. These two packages contained elevated moisture levels, although not significantly higher than seen in other 'typical' packages. The fiberboard in these two packages was of sound integrity, and appeared generally consistent with undegraded material. A few small patches of mold on and near the bottom of the fiberboard in 9975-01903 appeared dormant. No mold was observed on package 9975-02287. The SPA will provide recommendations on possible follow-up activities with these three packages. This might include a demonstration in SRNL of whether removal of the caplugs from similar packages would facilitate removal of excess moisture. Future efforts should also include an assessment of using the 1 inch axial gap criterion as a valid indicator of fiberboard degradation.
Date: November 18, 2009
Creator: Daugherty, W.
Partner: UNT Libraries Government Documents Department

Finite element modeling for validation of structural damage identification experimentation.

Description: The project described in this report was performed to couple experimental and analytical techniques in the field of structural health monitoring and darnage identification. To do this, a finite dement model was Constructed of a simulated three-story building used for damage identification experiments. The model was used in conjunction with data from thie physical structure to research damage identification algorithms. Of particular interest was modeling slip in joints as a function of bolt torque and predicting the smallest change of torque that could be detected experimentally. After being validated with results from the physical structure, the model was used to produce data to test the capabilities of damage identification algorithms. This report describes the finite element model constructed, the results obtained, and proposed future use of the model.
Date: January 1, 2001
Creator: Stinemates, D. W. (Daniel W.) & Bennett, J. G. (Joel G.)
Partner: UNT Libraries Government Documents Department

Damping dependence on bolt torque for a simple frame structure.

Description: Damping quantifies the energy dissipation properties of a material or system under cyclic stress. Damping is also one of the most difficult properties of a mechanical structure to model using first principles (Ewins, 2002) . Damping in uniform metal structures is often low. In built up structures dissipation occurs at mechanical joints or through introduction of viscoelastic materials ( Ungar, 1973, Goodman, 1996) . Energy dissipation at joints, associated with microslip, macroslip and hystersis increases the total damping of a structure so built up structures virtually always have greater damping than structures composed of a single part . Since damping is sensitive to interface properties, damping is a good feature for quantifying interface condition.
Date: January 1, 2003
Creator: Hunter, N. F. (Norman F.) & Paez, Thomas L.,
Partner: UNT Libraries Government Documents Department

Wire brush fastening device

Description: A fastening device is provided which is a variation on the conventional nut and bolt. The bolt has a longitudinal axis and threading helically affixed thereon along the longitudinal axis. A nut having a bore extending therethrough is provided. The bore of the nut has a greater diameter than the diameter of the bolt so the bolt can extend through the bore. An array of wire bristles are affixed within the bore so as to form a brush. The wire bristles extend inwardly from the bore and are constructed and arranged of the correct size, length and stiffness to guide the bolt within the bore and to restrain the bolt within the bore as required. A variety of applications of the wire brush nut are disclosed, including a bolt capture device and a test rig apparatus.
Date: August 31, 1993
Creator: Meigs, R.A.
Partner: UNT Libraries Government Documents Department

Second Annual Maintenance, Inspection, and Test Report for PAS-1 Cask Certification for Shipping Payload B

Description: The Nuclear Packaging, Inc. (NuPac), PAS-1 cask is required to undergo annual maintenance and inspections to retain certification in accordance with U.S. Department of Energy (DOE) Certificate of Compliance USA/9184B(U) (Appendix A). The packaging configuration being tested and maintained is the NuPac PAS-1 cask for Payload B. The intent of the maintenance and inspections is to ensure the packaging remains in unimpaired physical condition. Two casks, serial numbers 2162-026 and 2162-027, were maintained, inspected, and tested at the 306E Development, Fabrication, and Test Laboratory, located at the Hanford Site's 300 Area. Waste Management Federal Services, Inc. (WMFS), a subsidiary of GTS Duratek, was in charge of the maintenance and testing. Cogema Engineering Corporation (Cogema) directed the operations in the test facility. The maintenance, testing, and inspections were conducted successfully with both PAS-1 casks. The work conducted on the overpacks included weighing, gasket replacement, and plastic pipe plug and foam inspections. The work conducted on the secondary containment vessel (SCV) consisted of visual inspection of the vessel and threaded parts (i.e., fasteners), visual inspection of sealing surfaces, replacement of O-ring seals, and a helium leak test. The work conducted on the primary containment vessel (PCV) consisted of visual inspection of the vessel and threaded parts (i.e., fasteners), visual inspection of sealing surfaces, replacement of O-ring seals, dimensional inspection of the vessel bottom, a helium leak test, and dye penetrant inspection of the welds. The vermiculite material used in the cask rack assembly was replaced.
Date: October 9, 2000
Creator: KELLY, D.J.
Partner: UNT Libraries Government Documents Department

Evaluation of PEGIT duct connection system

Description: Most air duct system components are assembled in the field and are mechanically fastened by sheet metal screws (for sheet metal-to-sheet metal) or by drawbands (for flex duct-to-sheet metal). Air sealing is separate from this mechanical fastening and is usually achieved using tape or mastic products after mechanical fastening. Field observations have shown that mechanical fastening rarely meets code or manufacturers requirements and that sealing procedures are similarly inconsistent. To address these problems, Proctor Engineering Group (PEG) is developing a system of joining ducts (called PEGIT) that combines the mechanical fastening and sealing into a single self-contained procedure. The PEGIT system uses a shaped flexible seal between specially designed sheet metal duct fittings to both seal and fasten duct sections together. Figure 1 shows the inner duct fitting complete with rubber seal. This seal provides the air seal for the completed fitting and is shaped to allow the inner and outer fittings to slide together, and then to lock the fittings in place. The illustration in Figure 2 shows the approximate cross section of the rubber seal that shows how the seal has a lip that is angled backwards. This angled lip allows the joint to be pushed together by folding flat but then its long axis makes it stiff in the pulling apart direction. This study was undertaken to assist PEG in some of the design aspects of this system and to test the performance of the PEGIT system. This study was carried out in three phases. The initial phase evaluated the performance of a preliminary seal design for the PEGIT system. After the first phase, the seal was redesigned and this new seal was evaluated in the second phase of testing. The third phase performed more detailed testing of the second seal design to optimize the production tolerances ...
Date: August 1, 2003
Creator: Walker, Iain S.; Brenner, Douglas E.; Sherman, Max H. & Dickerhoff, Darryl J.
Partner: UNT Libraries Government Documents Department

Stainless steel quadralatch finger test report

Description: The design of the quadralatch on the universal samplers was changed in response to flammable gas operating constraints. Additional redesign of the fingers was included to facilitate manufacturability. The new design was tested to assure satisfactory performance. It was shown that the fingers can hold a sampler in place with an upward force of at least 2200 N (500 pounds) and that the mechanical remote latch unit can release the quadralatch under this condition of maximum upward force.
Date: June 20, 1996
Creator: Deichelbohrer, P.R.
Partner: UNT Libraries Government Documents Department

Stress Corrosion Crack Detection on HU-25 Guardian Aircraft

Description: Several ultrasonic inspection methods were developed at the Federal Aviation Administration's Airworthiness Assurance NDI Validation Center (AANC) to easily and rapidly detect hidden stress corrosion cracks in all vertical windshield posts on the US Coast Guard (USCG) HU-25 Guardian aircraft. The inspection procedure locates cracks as small as 2.0 millimeters emanating from internal fastener holes and determines their length. A test procedure was developed and a baseline assessment of the USCG fleet was conducted. Inspection results on twenty-five aircraft revealed a good correlation with results made during subsequent structural disassembly and visual inspection.
Date: February 17, 1999
Creator: Blackmon, R.; Huffman, J.; Mello, C.W.; Moore, D.G. & Walkington, P.D.
Partner: UNT Libraries Government Documents Department

Direct laboratory tensile testing of select yielding rock bolt systems

Description: Yielding rock bolt support systems have been developed to accommodate ground movement in shifting ground such as in coal operations; in creeping ground such as salt, trona, and potash; and in swelling ground associated with some clays. These systems, designed to remain intact despite ground movement, should enhance mine safety and help contain costs in areas where rebolting of rigid non-yielding systems is typically required. Four such systems were tested in straight tensile pulls in the laboratory. They include the Slip Nut System from Dywidag Systems International USA, Inc., Ischebeck`s bolt mounted Titan Load Indicator, Rocky Mountain Bolt Company`s Yielding Cable Bolt, and a rock bolt installed variation of the yielding steel post developed by RE/SPEC Inc. The first two systems are currently marketed products and the latter two are prototype systems. Each system responds to load and displacement by yielding in an unique manner. All are designed to yield at predetermined loads. A description of each system and its yield function is provided. Each system was tested over its prescribed yield range in a test machine. At least five tests were performed on each system. Each system yielded and continued to provide support according to its design. Each shows promise for ground control use in shifting or creeping rock. This work helps to illustrate the comparative differences in performance between these specialized systems and the applications where they may be most useful.
Date: August 1, 1996
Creator: VandeKraats, J.D. & Watson, S.O.
Partner: UNT Libraries Government Documents Department

Environmental research brief: Pollution prevention assessment for a manufacturer of metal fasteners

Description: The US Environmental Protection Agency (EPA) has funded a pilot project to assist small and medium-size manufacturers who want to minimize their generation of waste but who lack the expertise to do so. In an effort to assist these manufacturers Waste Minimization Assessment Centers (WMACs) were established at selected universities and procedures were adapted from the EPA Waste Minimization Opportunity Assessment Manual (EPA/625/7-88/003, July 1988). That document has been superseded by the Facility Pollution Prevention Guide (EPA/600/R-92/088, May 1992). The WMAC team at the University of Tennessee performed an assessment at a plant that manufactures various types of metal fasteners for automobiles, furniture, and appliances. Products are manufactured from steel, brass, copper, and aluminum wire and rod stock in two production lines-large part production and small part production. In large part production, header machines press wire stock into specific product shapes which are washed, machined, and in some cases heat-treated and polished. Small parts are manufactured from wire and rod stock in a series of machining operations, then washed, heat treated and polished, before shipment to an outside firm for surface finishing. The team`s report, detailing findings and recommendations indicated that a large amount of plant oil waste is shipped off-site for fuels blending and a significant quantity of oily sludge waste is shipped offsite for disposal as non-hazardous waste. Large cost savings can be achieved by the plant through the use of alternative methods of removing metal chips from parts, thereby reducing intermediate washings.
Date: August 1, 1995
Creator: Jendrucko, R.J.; Coleman, T.N. & Looby, G.P.
Partner: UNT Libraries Government Documents Department

Equipment design guidelines for remote hot cell operations.

Description: Hot cells provide a unique and challenging environment for designing remotely operated equipment. A typical hot cell is an isolated room used to protect operators from highly contaminated and radioactive equipment. Hot cells usually have thick reinforced concrete walk and leaded glass windows. Operations within the hot cell are accomplished using master-slave manipulators and overhead crane or electro-mechanical manipulator systems. The inability to perform hands-on operation and maintenance in hot cells requires special design considerations. Some of these design considerations include operational interfaces, radiation, accessibility, replaceability/interchangeability, decontamination, atmospheric conditions, functionality, operator fatigue, and ease of use. This paper will discuss guidelines for designing hot cell remotely operated equipment that has been used successfully at Argonne National Laboratory. General topics in this paper will include master-slave manipulator types and limitations, overhead handling systems, viewing limitations, types and sizes of typical fasteners, hot cell compatible materials, mockup testing, guide features for mating parts, modularity, labeling, electrical fasteners, and lifting fixtures.
Date: July 10, 1998
Creator: Wahlquist, D. R.
Partner: UNT Libraries Government Documents Department

Formal Design Review Foot Clamp Modification

Description: This report documents the Design Review performed for the foot clamp modification. The report documents the acceptability of the design, identifies the documents that were reviewed, the scope of the review and the members of the review team.
Date: January 24, 2000
Creator: OTEN, T.C.
Partner: UNT Libraries Government Documents Department

Probing the Elastic-Plastic, Time-Dependant Response of Test Fasteners using Finite Element Analysis (FEA)

Description: The evolution of global and local stress/strain conditions in test fasteners under test conditions is investigated using elastic-plastic, time-dependent finite element analyses (FEA). For elastic-plastic response, tensile data from multiple specimens, material heats and test temperatures are integrated into a single, normalized flow curve from which temperature dependency is extracted. A primary creep model is calibrated with specimen- and fastener-based thermal relaxation data generated under a range of times, temperatures, stress levels and environments. These material inputs are used in analytical simulations of experimental test conditions for several types of fasteners. These fastener models are constructed with automated routines and contact conditions prescribed at all potentially mating surfaces. Thermal or mechanical room temperature pre-loading, as appropriate for a given fastener, is followed by a temperature ramp and a dwell time at constant temperature. While the amount of thermal stress relaxation is limited for the conditions modeled, local stress states are highly dependent upon geometry (thread root radius, for example), pre-loading history and thermal expansion differences between the test fastener and test fixture. Benefits of this FE approach over an elastic methodology for stress calculation will be illustrated with correlations of Stress Corrosion Cracking (SCC) initiation time and crack orientations in stress concentrations.
Date: December 13, 2004
Creator: Renauld, ML & Lien, H
Partner: UNT Libraries Government Documents Department