72 Matching Results

Search Results

Advanced search parameters have been applied.

Spin-tunnel investigation to determine the effect on spin recoveries of reducing the opening shock load of spin-recovery parachutes

Description: Report presenting an investigation in the 20-foot free-spinning tunnel to determine whether the effectiveness of a spin-recovery parachute would be influenced by a reduction, through the use of a shock absorber, or the opening shock load. The results indicated that a given spin-recovery parachute was effective with or without a rubber shock absorber installed in the parachute towline. Results regarding the effect of the shock absorber on spin-recovery characteristics and effect of porosity and towline length on shock load are provided.
Date: March 1950
Creator: Jones, Ira P., Jr. & Klinar, Walter J.
Partner: UNT Libraries Government Documents Department

Shock-Absorbing Materials, Report 2: Cellular Concrete as a Backpacking Material

Description: Partial abstract: "The use of low-density cellular concrete, having an oven-dry unit weight of 50 pcf or less, as a backpacking material for deeply buried protective structures was studied. Cellular concrete was found to be suitable for this type of application. A number of physical properties of cellular concrete were determined to provide input to design codes" (p. 4).
Date: June 1971
Creator: Hoff, G. C.
Partner: UNT Libraries Government Documents Department

High shock, high frequency characteristics of a mechanical isolator for a piezoresistive accelerometer

Description: A mechanical isolator has been developed for a piezoresistive accelerometer. The purpose of the isolator is to mitigate high frequency shocks before they reach the accelerometer because the high frequency shocks may cause the accelerometer to resonate. Since the accelerometer is undamped, it often breaks when it resonates. The mechanical isolator was developed in response to impact test requirements for a variety of structures at Sandia National Laboratories. An Extended Technical Assistance Program with the accelerometer manufacturer has resulted in a commercial isolator that will be available to the general public. This mechanical isolator has ten times the bandwidth of any other commercial isolator and has acceptable frequency domain performance from DC to 10 kHz ({plus_minus} 10%) over a temperature range of -65{degrees}F to +185{degrees}F as demonstrated in this paper.
Date: July 1, 1995
Creator: Bateman, V.I.; Brown, F.A. & Davie, N.T.
Partner: UNT Libraries Government Documents Department


Description: Polyurethane foam has been employed in impact limiters for large radioactive materials packagings since the early 1980's. Its consistent crush response, controllable structural properties and excellent thermal insulating characteristics have made it attractive as replacement for the widely used cane fiberboard for smaller, drum size packagings. Accordingly, polyurethane foam was chosen for the overpack material for the 9977 and 9978 packagings. The study reported here was undertaken to provide data to support the analyses performed as part of the development of the 9977 and 9978, and compared property values reported in the literature with published property values and test results for foam specimens taken from a prototype 9977 packaging. The study confirmed that, polyurethane foam behaves in a predictable and consistent manner and fully satisfies the functional requirements for impact absorption and thermal insulation.
Date: February 18, 2009
Creator: Smith, A; Glenn Abramczyk, G; Paul Blanton, P; Steve Bellamy, S; William Daugherty, W & Sharon Williamson, S
Partner: UNT Libraries Government Documents Department


Description: This paper evaluates the effect of the impact limiter material degradation on the structural integrity of the 9975 package containment vessel during a postulated accident event of forklift truck collision. The analytical results show that the primary and secondary containment vessels remain structurally intact for Celotex material degraded to 20% of the baseline value.
Date: July 9, 2007
Creator: Wu, T
Partner: UNT Libraries Government Documents Department

Blast mitigation capabilities of aqueous foam.

Description: A series of tests involving detonation of high explosive blanketed by aqueous foam (conducted from 1982 to 1984) are described in primarily terms of recorded peak pressure, positive phase specific impulse, and time of arrival. The investigation showed that optimal blast mitigation occurs for foams with an expansion ratio of about 60:1. Simple analyses representing the foam as a shocked single phase mixture are presented and shown inadequate. The experimental data demonstrate that foam slows down and broadens the propagated pressure disturbance relative to a shock in air. Shaped charges and flyer plates were evaluated for operation in foam and appreciable degradation was observed for the flyer plates due to drag created by the foam.
Date: February 1, 2006
Creator: Hartman, William Franklin; Larsen, Marvin Elwood & Boughton, Bruce A.
Partner: UNT Libraries Government Documents Department


Description: Polyurethane foam has been widely used as an impact absorbing and thermal insulating material for large radioactive materials packages, since the 1980's. With the adoption of the regulatory crush test requirement, for smaller packages, polyurethane foam has been adopted as a replacement for cane fiberboard, because of its ability to withstand the crush test. Polyurethane foam is an engineered material whose composition is much more closely controlled than that of cane fiberboard. In addition, the properties of the foam can be controlled by controlling the density of the foam. The conditions under which the foam is formed, whether confined or unconfined have an affect on foam properties. The study reported here reviewed the application of polyurethane foam in RAM packagings and compared property values reported in the literature with published property values and test results for foam specimens taken from a prototype 9977 packaging. The study confirmed that, polyurethane foam behaves in a predictable and consistent manner and fully satisfies the functional requirements for impact absorption and thermal insulation.
Date: May 15, 2007
Creator: Smith, A; Glenn Abramczyk, G; Paul Blanton, P; Steve Bellamy, S; William Daugherty, W & Sharon Williamson, S
Partner: UNT Libraries Government Documents Department


Description: Cane-based Celotex{trademark} has been used extensively in various DOE packages as a thermal insulator and impact absorber. Cane-based Celotex{trademark} for the 9975 was manufactured by Knight-Celotex Fiberboard at their Marrero Plant in Louisiana. However, Knight-Celotex Fiberboard shut down their Marrero Plant in early 2007 due to impacts from hurricane Katrina and other economic factors. Therefore, cane-based Celotex{trademark} is no longer available for use in the manufacture of new 9975 packages. Knight-Celotex Fiberboard has Celotex{trademark} manufacturing plants in Danville, VA and Sunbury, PA that use softwood and hardwood, respectively, as a raw material in the manufacturing of Celotex{trademark}. The purpose of this White Paper is to demonstrate that softwood-based Celotex{trademark} from the Knight-Celotex Danville Plant has performance equivalent to cane-based Celotex{trademark} from the Knight-Celotex Marrero Plant for transportation in a 9975 package.
Date: November 20, 2007
Creator: Varble, J
Partner: UNT Libraries Government Documents Department

Active noise and vibration control for vehicular applications

Description: This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). This project investigated semi-active suspension systems based on real time nonlinear control of magneto-rheological (MR) shock absorbers. This effort was motivated by Laboratory interactions with the automobile industry and with the Defense Department. Background research and a literature search on semi-active suspensions was carried out. Numerical simulations of alternative nonlinear control algorithms were developed and adapted for use with an MR shock absorber. A benchtop demonstration system was designed, including control electronics and a mechanical demonstration fixture to hold the damper/spring assembly. A custom-made MR shock was specified and procured. Measurements were carried out at Los Alamos to characterize the performance of the device.
Date: December 31, 1998
Creator: Lewis, P.S. & Ellis, S.
Partner: UNT Libraries Government Documents Department

Seismic tipping analysis of a spent nuclear fuel shipping cask sitting on a crush pad

Description: A crush pad has been designed and analyzed to absorb the kinetic energy of an accidentally dropped spent nuclear fuel shipping cask into a 44 ft. deep cask unloading pool. Conventional analysis techniques available for evaluating a cask for tipping due to lateral seismic forces assume that the cask rests on a rigid surface. In this analysis, the cask (110 tons) sits on a stainless steel encased (0.25 in. top plate), polyurethane foam (4 ft. thick) crush pad. As the cask tends to rock due to horizontal seismic forces, the contact area between the cask and the crush pad is reduced, increasing the bearing stress, and causing the pivoting corner of the cask to depress into the crush pad. As the crush pad depresses under the cask corner, the pivot point shifts from the corner toward the cask center, which facilitates rocking and potential tipping of the cask. Subsequent rocking of the cask may deepen the depression, further contributing to the likelihood of cask tip over. However, as the depression is created, the crush pad is absorbing energy from the rocking cask. Potential tip over of the cask was evaluated by performing a non-linear, dynamic, finite element analysis with acceleration time history input. This time history analysis captured the effect of a deforming crush pad, and also eliminated conservatisms of the conventional approaches. For comparison purposes, this analysis was also performed with the cask sitting on a solid stainless steel crush pad. Results indicate that the conventional methods are quite conservative relative to the more exacting time history analysis. They also indicate that the rocking motion is less on the foam crush pad than on the solid stainless steel pad.
Date: April 1, 1998
Creator: Uldrich, E.D. & Hawkes, B.D.
Partner: UNT Libraries Government Documents Department

A Preliminary Study of Energy Recovery in Vehicles by Using Regenerative Magnetic Shock Absorbers

Description: Road vehicles can expend a significant amount of energy in undesirable vertical motions that are induced by road bumps, and much of that is dissipated in conventional shock absorbers as they dampen the vertical motions. Presented in this paper are some of the results of a study aimed at determining the effectiveness of efficiently transforming that energy into electrical power by using optimally designed regenerative electromagnetic shock absorbers. In turn, the electrical power can be used to recharge batteries or other efficient energy storage devices (e.g., flywheels) rather than be dissipated. The results of the study are encouraging - they suggest that a significant amount of the vertical motion energy can be recovered and stored.
Date: May 14, 2001
Creator: Goldner, R. B.; Zerigian, P. & Hull, J. R.
Partner: UNT Libraries Government Documents Department

Directly Susceptible, Noncarbon Composite Crucible

Description: A sintered metal ceramic crucible suitable for high temperature induction melting of reactive metals without appreciable carbon or silicon contamination of the melt. The crucible comprises a cast matrix of a thermally conductive ceramic material; a perforated metal sleeve, which serves as a susceptor for induction heating of the crucible, embedded within the ceramic cast matrix; and a thermal-shock-absorber barrier interposed between the metal sleeve and the ceramic cast matrix to allow for differential thermal expansions between the matrix and the metal sleeve and to act as a thermal-shock-absorber which moderates the effects of rapid changes of sleeve temperature on the matrix.
Date: November 25, 1998
Creator: Holcombe, Cressie E.,Jr.; Kiggans, James O., Jr.; Morrow, Marvin S. & Rexford, Donald
Partner: UNT Libraries Government Documents Department


Description: The project continues to advance approximately per the revised (14-month) schedule. Tasks 1-3 (Modeling, Specification and Design) are all essentially complete. Work has begun on designing the test equipment for the Test and Evaluation (Tasks 4 & 5.) One of the intents of this project is to not only dampen vibration above the damper, but to also dampen vibrations below the damper. This is accomplished by smoothing out the discontinuities as the bit drills ahead. The model has the capability to simulate the drilling looking at the depth of cut along the discontinuities. It can also look at the amount of time that the bit is in contact with the formation. It is found that under some conditions the vibrations increased the discontinuities due to resonant conditions. In the ideal situation, the damper reduces the discontinuities and smooths out the drilling. APS looked at a wide range of spring stiffness and damping properties to determine the optimum damper. Spring rates of 10,000 lb/in to 60,000 lbs/in were analyzed. The best compromise is at 30,000 lb/in for the 6 3/4 inch tool. Low spring rates would require large displacements for the damper, while stiff springs do not provide enough motion for the damper. Several damping concepts were analyzed: (1) The first thought was to have a damper providing high damping in the upward direction and low damping in the downward direction. It was found that this increased the vibration by wallowing out the troughs of the discontinuities leading to increased displacements at the bit. (2) Another method investigated was having increased damping at high acceleration levels and less damping at lower acceleration levels. This gave improved results. (3) Constant damping so far provides the damping situation. With the proper damping level the damper can smooth out the discontinuities and provide smooth ...
Date: April 1, 2003
Creator: Cobern, Martin E.
Partner: UNT Libraries Government Documents Department

Modeling the behavior of an earthquake base-isolated building.

Description: Protecting a structure against earthquake excitation by supporting it on laminated elastomeric bearings has become a widely accepted practice. The ability to perform accurate simulation of the system, including FEA of the bearings, would be desirable--especially for key installations. In this paper attempts to model the behavior of elastomeric earthquake bearings are outlined. Attention is focused on modeling highly-filled, low-modulus, high-damping elastomeric isolator systems; comparisons are made between standard triboelastic solid model predictions and test results.
Date: November 26, 1997
Creator: Coveney, V. A.; Jamil, S.; Johnson, D. E.; Kulak, R. F. & Uras, R. A.
Partner: UNT Libraries Government Documents Department


Description: Two layers of insulation fill the volume of the 9977 package between the drum liner and the shell. One of these layers is composed of General Plastics FR-3716 polyurethane foam (also known as Last-A-Foam{reg_sign}), poured through fill holes in the drum bottom and foamed in place. There was concern that the density of the foam insulating layer may vary due to the manufacturing process and that variations in foam density would compromise the safety basis of the package. Thus, a structural finite element analysis was performed to investigate this concern. The investigation examined the effect of replacing the material properties for the FR-3716 polyurethane foam, which has a density equal to 16 lb{sub m}/ft{sup 3}, with material properties of similar foam with varying densities through finite element analysis of hypothetical accident conditions (HAC) pertaining to impact conditions. The results showed that the functional performance of the containment vessel (CV) was not compromised under the conditions investigated.
Date: May 2, 2008
Creator: Gorczyca, J & Tsu-Te Wu, T
Partner: UNT Libraries Government Documents Department


Description: The fiberboard assembly used in 9975 shipping packages as an impact-absorption and insulation component has the capacity to absorb moisture, with an accompanying change to its properties. While package fabrication requirements generally maintain the fiberboard moisture content within manufacturing range, there is the potential during use or storage for atypical handling or storage practices which result in the absorption of additional moisture. In addition to performing a transportation function, the 9975 shipping packages are used as a facility storage system for special nuclear materials at the Savannah River Site. A small number of packages after extended storage have been found to contain elevated moisture levels. Typically, this condition is accompanied by an axial compaction of the bottom fiberboard layers, and the growth of mold. In addition to potential atypical practices, fiberboard can exchange moisture with the surrounding air, depending on the ambient humidity. Laboratory data have been generated to correlate the equilibrium moisture content of cane fiberboard with the humidity of the surrounding air. These data are compared to measurements taken within shipping packages. With a reasonable measurement of the fiberboard moisture content, an estimate of the fiberboard properties can be made. Over time, elevated moisture levels will negatively impact performance properties, and promote fiberboard mold growth and resultant degradation.
Date: February 11, 2010
Creator: Daugherty, W.; Dunn, K.; Murphy, J. & Hackney, B.
Partner: UNT Libraries Government Documents Department

Characterizing large strain crush response of redwood

Description: Containers for the transportation of hazardous and radioactive materials incorporate redwood in impact limiters. Redwood is an excellent energy absorber, but only the most rudimentary information exists on its crush properties. The objectives of the study were to fill the information gap by collecting triaxial load-deformation data for redwood; to use these data to characterize redwood crush, assess current wood failure theories, provide developments toward a complete stress-strain theory for redwood; and to review the literature on strain-rate effects on redwood crush performance. The load-deformation responses of redwood at temperature conditions corresponding to ambient (70{degrees}F), 150{degrees}F, and {minus}20{degrees}F conditions were measured in approximately 100 confined compression tests for crush levels leading to material densification. Data analysis provided a more complete description of redwood crush performance and a basis for assessing proposed general orthotropic stress-strain relationships for redwood. A review of existing literature indicated that strain-rate effects cause at most a 20 percent increase in crush stress parallel to grain.
Date: December 1, 1996
Creator: Cramer, S.M.; Hermanson, J.C. & McMurtry, W.M.
Partner: UNT Libraries Government Documents Department

Analysis for SNF Multi Canister Overpack (MCO) Drop into the Cask from the MCO Handling Machine (MHM) with Air Cushion

Description: The purpose of this report is to investigate the potential for damage to the MCO during impact from an accidental drop from the MHM into the shipping cask. The MCO is dropped from a height of 8.2 feet above the cask enters the cask concentrically and falls the additional 12.83 feet to the cask bottom. Because of the interface fit between the MCO and the cask and the air entrapment the MCO fall velocity is slowed. The shipping cask is resting on an impact absorber at the time of impact. The energy absorbing properties of the impact absorber are included in this analysis.
Date: January 12, 2000
Creator: RAINS, D.J.
Partner: UNT Libraries Government Documents Department

Thermal conductivity of cane fiberboard

Description: The thermal conductivity of cane fiberboard was measured in two planes; parallel to the surface and perpendicular to the surface of the manufactured sheet. The information was necessary to better understand the thermal response of a loaded shipping container. The tests demonstrated that the thermal conductivity of cane fiberboard in the plane parallel to the surface of the sheet was nearly twice as great as the conductivity of the same material in a plane perpendicular to the sheet. There was no significant difference in the conductivity in different directions within the plane parallel to the surface, and the presence of glue between layers of fiberboard did not significantly change the conductivity of the assembly. The tests revealed that the thermal conductivity measured in a direction perpendicular to the plane of the surface of a stack of cane fiberboard sheets not bonded together, decreases with an increase in the mean temperature. This was determined to be the result of air gaps between the sheets of fiberboard, and not related to the properties of the material itself
Date: May 1, 1995
Creator: Leader, D.R.
Partner: UNT Libraries Government Documents Department

Certification testing for the ES-2 shipping package

Description: The ES-2 is a multiconfiguration, Type B fissile material shipping package, designed by the Y-12 Nuclear Packaging Systems. It is unique in that a castable refractory material performs primary impact absorption and thermal insulation duties. This material, unlike the insulation often used in fissile material packages, such as Celotex and various foams, is fireproof at temperatures associated with Type B package testing (800 C). The ES-2 is designed to permit the use of three different containment vessels which can result in as many as six different configurations. Eight prototype units were manufactured and successfully tested to US Federal Regulatory Requirements.
Date: February 1, 1998
Creator: Feldman, M.R.; Byington, G.A.; Handy, K.D.; Shappert, L.B.; Handy, K.D.; Oaks, R.E. Jr. et al.
Partner: UNT Libraries Government Documents Department

Factors affecting characterization of bulk high-temperature superconductors

Description: Three major factors affect the characterization of bulk high-temperature superconductors in terms of their levitation properties during interaction with permanent magnets. First, the appropriate parameter for the permanent magnet is internal magnetization, not the value of the magnetic field measured at the magnet`s surface. Second, although levitation force grows with superconductor thickness and surface area, for a given permanent magnet size, comparison of levitation force between samples is meaningful when minimum values are assigned to the superconductor size parameters. Finally, the effect of force creep must be considered when time-averaging the force measurements. In addition to levitational force, the coefficient of friction of a levitated rotating permanent magnet may be used to characterize the superconductor.
Date: November 1, 1997
Creator: Hull, J.R.
Partner: UNT Libraries Government Documents Department

Discrete optimization of isolator locations for vibration isolation systems: An analytical and experimental investigation

Description: An analytical and experimental study is conducted to investigate the effect of isolator locations on the effectiveness of vibration isolation systems. The study uses isolators with fixed properties and evaluates potential improvements to the isolation system that can be achieved by optimizing isolator locations. Because the available locations for the isolators are discrete in this application, a Genetic Algorithm (GA) is used as the optimization method. The system is modeled in MATLAB{trademark} and coupled with the GA available in the DAKOTA optimization toolkit under development at Sandia National Laboratories. Design constraints dictated by hardware and experimental limitations are implemented through penalty function techniques. A series of GA runs reveal difficulties in the search on this heavily constrained, multimodal, discrete problem. However, the GA runs provide a variety of optimized designs with predicted performance from 30 to 70 times better than a baseline configuration. An alternate approach is also tested on this problem: it uses continuous optimization, followed by rounding of the solution to neighboring discrete configurations. Results show that this approach leads to either infeasible or poor designs. Finally, a number of optimized designs obtained from the GA searches are tested in the laboratory and compared to the baseline design. These experimental results show a 7 to 46 times improvement in vibration isolation from the baseline configuration.
Date: May 17, 1996
Creator: Ponslet, E.R. & Eldred, M.S.
Partner: UNT Libraries Government Documents Department