bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of Vickers V-104 and 20VQ5 Vane Pumps for ASTM D-2882 Wear Tests Using Water-Glycol Hydraulic Fluids
Authors: Totten GE , Bishop RJ 
Published: March 2009

Work is currently underway within the ASTM D.02 N.07 “Hydraulic Fluid Testing” Committee to evaluate the potential of replacing the Vickers V-104 vane pump with a newer, more current model, 20VQ vane pump for use in an updated ASTM D-2882 and other national standards. All of the round robin work conducted within the committee thus far has involved the use of non-aqueous hydraulic oils. Although there are some significant inter-laboratory reproducibility problems, it appears that the overall ranking of the hydraulic oils by most laboratories appears to be consistent.
To further evaluate the potential utility of replacing the Vickers V-104 pump with the 20VQ pump, a series of different water-glycol hydraulic fluid formulations with significantly different wear rates were evaluated using a “modified” ASTM D-2882 testing procedure. The results showed that expected catastrophic pump failures, which occurred with the V-104 pump, not only did not occur with the 20VQ pump, but the relative orders of wear rates for some of the fluids were also different.
In this paper, a brief history of the development of the ASTM D- 2882 test, as currently conducted, will be presented, a comparison of the features of the V-104 and 20VQ pump and cartridge assemblies will be given and a comparative tabulation of the pump test using the V-104 pump and the 20VQ pump using different testing conditions will be provided. Finally, recommendations for future work will be made.
Standardized Hydraulic Fluid Testing — an Overview and History
Authors: Jackson JM , Marty SD 
Published: March 2009

In order for a hydraulic fluid to be approved by the various pump manufacturers for use in their products, it must qualify for acceptance according to certain test methods. Chief among these tests are the Denison HF-0, the Vickers 35VQ25, and the John Deere Sundstrand piston pump test.
The Denison HF-0 test evaluates hydraulic fluid performance based on flow, deposits, and wear in both a Denison P46 axial piston pump and a Denison T5D vane pump. Both pumps are run for 100 hours and are periodically disassembled for inspection. Obtaining satisfactory pump results is the largest step in the process for a fluid to qualify under the HF-0 Standard. In the past, the P46 and T5D pumps could be tested separately or “bootstrapped” with a 46 series motor to reduce horsepower requirements.
The Vickers 35VQ25 test measures the anti-wear characteristics of a hydraulic oil according to cam ring and vane weight loss in a 35VQ25 vane pump. A minimum of three cartridges are tested for 50 hours each. The first three, or four of five cartridges, must perform satisfactorily in order for a fluid to pass this test.
The John Deere piston pump test screens oils that cause corrosion of copper containing metals. A Sundstrand 22 series axial piston pump is operated for 25 hours. Water is then added to the test oil. The test is then run for 200 more hours. Over this time multiple parameters are monitored to determine the effect of the added water.
Creep Damage and Creep-Fatigue Damage Interaction Model for Unidirectional Metal-Matrix Composites
Authors: Kruch S , Arnold SM 
Published: March 2009

A multiaxial, isothermal, continuum damage mechanics model for creep and creep-fatigue interaction of a unidirectional metal-matrix composite (MMC) volume element is presented. The model is phenomenological, stress based, and assumes a single scalar internal damage variable with directional-dependent evolution. The present creep damage model is an extension of the Leckie-Hayhurst creep damage model to unidirectional MMCs and is shown when taken to its isotropic limit, to directly simplify to this previously developed and validated isotropic creep damage model. This extension is accomplished by introducing into the isochronous damage function physically meaningful stress invariants that reflect the local stress and material orientation within a metallic, transversely isotropic material (for example, hexagonally packed unidirectional metal-matrix composite). These invariants are included based on the anticipation that the associated stress may strongly influence void growth at the fiber-matrix interface (as this interface is postulated to play a role, on the mesostructural scale, analogous to that of grain boundaries on the microstructural scale and interfacial degradation); and, consequently may correlate with a creep rupture mechanism based on interfacial degradation through diffusion-related void growth.
Creep-fatigue interaction is accomplished by directly adding together the mechanical effects of creep and fatigue damage. A uniaxial parametric study is performed under pure creep and creep-fatigue conditions, to demonstrate the sensitivity of the various material parameters and the capability of the formulation in attempting to characterize a class of composite materials. Specifically, two interaction regions will be examined, the first being important for low-frequency loading cycles (&lt;5 Hz) and is termed “creep-dominated” interaction; whereas the second is for high-frequency loading cycles with a non-zero mean stress, and is termed “fatigue-dominated” interaction. Results are presented in the form of S-N and damage accumulation curves.
A Model for Predicting the Effect of Environmental Degradation on Damage Evolution of Metal-Matrix Composites
Authors: Allen DH , Foulk JW , Helms KLE , Lagoudas DC 
Published: March 2009

A life prediction model is being developed by the authors for application to continuous fiber metal-matrix composites (MMCs). The specific systems considered in this study are silicon-carbide fibers imbedded in titanium matrix. Due to multiple nonlinearities, the model utilizes a computationally based framework derived from thermodynamics and continuum mechanics. Matrix inelasticity, damage evolution, and environmental degradation due to oxidation-related effects are also included within the model. To computationally implement the model, the finite element method is used with an evolutionary analysis of a unit cell accomplished via a time-stepping algorithm. Matrix inelasticity is modeled with the Bodner anisotropic hardening viscoplastic model. Damage growth such as fiber-matrix debonding, surface cracking, and matrix cracking is modeled via the inclusion of cohesive zone elements in the unit cell. The locations of these elements are chosen to correspond with experimentally observed damage. As environmental degradation varies in form, depending on the specific system, it is accounted for by including either an outer surface layer that is embrittled due to oxidation or degraded material properties that result from oxygen-induced changes in microstructure.
The current paper outlines the formulation utilized by the authors to solve this problem, and recent results are discussed. Specifically, results are given for a four-ply unidirectional composite subjected to monotonic and fatigue loadings. In both cases, environmental degradation influences the initiation and evolution of damage.
Effects of Damage Distribution on Evolution
Authors: Lacy TE , Talreja R , McDowell DL 
Published: March 2009

Recent micromechanically inspired phenomenological theories using internal state variable (ISV) representations of damage have been used to predict the thermomechanical behavior of microcracked solids. These models do not, in an explicit manner, account for distributions of microcracks in a representative volume element (RVE) and have been used successfully only to determine the effective moduli of damaged solids. It has been demonstrated that while the distribution and interaction of damage entities within an RVE generally have a minor effect on the effective moduli, it has a significant effect on the evolution of damage and failure at the macroscale. Damage evolution rates, in general, cannot be described adequately by such theories because of their inability to account for interactions between damage entities in an arbitrary distribution.
Key issues pertaining to the development of viable damage evolution equations using a continuum damage mechanics approach are addressed. In particular, limitations associated with the use of ISVs that can be expressed either in terms of macroscopically measurable quantities or through a spatial average of the geometric features of individual damage entities are discussed. Numerical simulations of evolving crack systems in two-dimensional perfectly brittle solids indicate that “effective stress” models may have difficulty in characterizing damage evolution in brittle microcracked solids when the damage consists of cracks of variable size or spatial distributions. An argument for implementing ISVs based on higher-order moments of the damage distribution within an RVE is presented.
A Unified Approach to Metal Fatigue Based on the Theory of Damage Mechanics
Authors: Chow CL , Yu LG 
Published: March 2009

This paper presents a unified approach to fatigue damage in metals based on the theory of damage mechanics. The theory that takes into account the gradual material degradation or deterioration under load is ideally suited for characterizing material behaviors progressively damaged under fatigue loading. This is because fatigue damage is caused by material degradation resulting from the initiation, growth, and coalescence of microcracks/voids in real-life materials under repeated/cyclic loading. In addition, a unified fracture criterion based on the damage mechanics theory has been developed to predict the threshold conditions of macrocrack initiation and propagation as well as damage evolution in a material element with or without the presence of a macrocrack. This type of unified approach would not otherwise be possible using the conventional fatigue design methodology based on either the S-N diagram or the concept of fracture mechanics.
The proposed fatigue damage model is based on the thermodynamic theory of irreversible processes with internal state variables. With the introduction of a new damage effect tensor, the necessary constitutive equations of elasticity and plasticity coupled with damage are developed. The constitutive equations derived enable the formulation of a fatigue damage dissipative potential function and a fatigue damage criterion. The criterion is designed to subdivide the overall damage into two domains, namely, “fatigue damage” and “plastic damage.” The fatigue damage evolution equation is subsequently developed based on the hypothesis that the overall damage is induced by the summation of “fatigue” and “plastic” damages. The model has been applied to predict successfully the fatigue life of smooth, notched, and center-cracked specimens under a wide range of loading cycles.
Assessment of a Semielliptical Crack in the Interface Between Ferritic and Austenitic Material on the Basis of the Gurson Model
Authors: Sun DZ , Schmitt W 
Published: March 2009

In safety analyses of nuclear reactor pressure vessels, hypothetical cracks are often postulated in the ferritic base material beneath the austenitic cladding that is used to protect against corrosion. The criticality of the hypothetical cracks is strongly influenced by the integrity of the cladding. If the cladding is intact, the crack tip loading is significantly reduced compared with the case where the cladding is assumed to be broken. The assessment of the load-carrying capacity of such a cladding cannot be done on the basis of the J-integral concept since its application is problematic at the interface of two materials and steep gradients in the material properties in the heat-affected zone cannot be characterized by fracture mechanics tests meaningfully. Moreover, the shape of cracks is usually assumed as semielliptical and the conventional J-concept has to be modified to take into account the effect of the constraint, changing along the crack front, on the crack resistance behavior. To avoid these problems, the behavior of a flaw in the interface between ferritic and austenitic material has been analyzed by a micromechanical material model based on the Gurson flow function.
A three-point-bend specimen consisting of a ferritic block with an austenitic cladding and a semielliptical crack in the ferritic base material beneath the cladding was tested and evaluated. The global (that is, load versus displacement curve) and local (that is, ductile crack extension in ferrite and austenite) behaviors of this specimen were predicted by means of two- and three-dimensional finite element analyses with the Gurson parameters determined for different material zones. The material characterization was done by utilizing subsized tension tests with improved evaluation and fracture mechanics tests with precracked Charpy-type specimens.
Viscoelastic Recovery of Creep-Deformed Ultra-High Molecular Weight Polyethylene (UHMWPE)
Authors: Lee K-Y , Pienkowski D 
Published: March 2009

Viscoelastic creep recovery of ultra-high molecular weight polyethylene (UHMWPE) was quantified as a function of time and applied pressure for both static and dynamic loading. Unirradiated extruded GUR 4150HP UHMWPE specimens were compressed by using static and dynamic (1-Hz sinusoidal) loads with clinically relevant (hip) peak pressures of 2, 4, and 8 MPa in 37°C bovine serum for 10 000 minutes. Thereafter, loads were removed and the thicknesses of the specimens were measured periodically in air for up to 10 000 minutes.The creep strains recovered as a function of log time for all pressures in both static and dynamic loading. Regardless of load amplitude, load type, and radial location from which the specimens were machined from the extruded rod stock, approximately 51 % of the total creep deformation was ultimately recovered, and 73% of the recovered creep strain occurred during the first 1000 min after unloading. These data emphasize the need to account for the amount of creep recovery when estimating wear rates with in vivo radiographic penetration measurements and the dimensions of retrieved implants.
A New Method to Determine the Locus of Radiation Damage in Retrieved Ultra-High Molecular Weight Polyethylene (UHMWPE) Components
Authors: Muratoğlu OK , Imlach H , Jasty M , Harris WH 
Published: March 2009

Gamma-sterilization can damage ultra-high molecular weight polyethylene (UHMWPE) that, after three to five years or more, can lead to the embrittlement of the polymer. In many cases, thin cross sections (100 μm) of the polymer have a gross appearance of a “white band,” generally 1 to 2 mm below the surface. This white band consists of cracks induced during sectioning in areas of embrittlement. We studied oxidation changes resulting in chain scission by exploring the effects of hot (110°C) xylene extraction on aged UHMWPE acetabular components. Hot xylene is a good solvent for polyethylenes and extracts the lower molecular weight species from UHMWPE. In so doing, it also extracts the lower molecular weight species that result from chain scission.
The xylene extraction studies revealed two interesting observations. First, the extent of extraction-induced white band was substantially in excess of the sectioning-induced white banding. The infrared determination of the oxidation extent was more accurately indicated by extraction than sectioning. Secondly, microscopic observation of the material prior to and after xylene extraction showed that the regions of greatest extraction of polyethylene were at the interfaces between individual flakes of the starting material. This observation indicates that a major site of preferential removal of polyethylene was at the interfaces and supports the concept of preferential O2 diffusion along the boundaries between the flakes of the original polyethylene resin.
Promoted Ignition-Combustion Behavior of Alternative High Performance Engineering Alloys in Oxygen-Enriched Atmospheres
Authors: McIlroy K , Zawierucha R , Million JF 
Published: March 2009

Promoted ignition and more recently promoted combustion are terms which have been used to describe a situation where a substance with low oxygen compatibility ignites and supports the combustion of a more combustion resistant material. Previous work has been reported on the investigation of this phenomenon as it relates to carbon steel, stainless steels and a number of significant engineering alloys in the nickel, cobalt and copper families.
Alloys which were tested in this investigation included: AL-6XN stainless steel, 347 stainless steel, INCO A weld filler metal, HAYNES HR-160, HAYNES 214, HAYNES 230, HAYNES 556 and HAYNES ULTIMET.
These alloys represent a substantial range of alloy composition, capability and cost. Potential service environments include hazardous waste, marine, heavy industrial, electronics and various elevated temperature applications where oxygen enriched environments may be encountered.
Flammability Tests of Miniature Brazed Aluminum Heat Exchangers in Liquid Oxygen
Authors: Zawierucha R , Million JF 
Published: March 2009

Most air separation plants currently in use employ compressors to increase oxygen pressure for customer usage. An alternative approach is to extract liquid oxygen from the separation column which is pumped to higher pressure and then boiled in a heat exchanger to directly provide an elevated pressure gaseous oxygen product. Brazed aluminum heat exchangers (BAHX) are normally utilized as the product oxygen vaporizers. The process results in substantial contact between high pressure liquid oxygen and aluminum material. The increased use of BAHXs to produce pressurized oxygen as an alternative to the use of oxygen compressors led to a series of experimental programs pertinent to the safe use of BAHXs for boiling oxygen at elevated pressures.
In the 1993 to 1995 period, 29 individual flammability experiments were conducted with 3 kg or 13 kg miniature headered BAHX samples. In the oxygen passages, commercial purity liquid oxygen was used at pressures ranging from 170 kPa to 6,996 kPa. Alternate passages contained air, nitrogen or oxygen at pressures ranging from 108 kPa to 10,443 kPa. Nichrome wire was used to ignite hydrocarbons placed within an oxygen passage to simulate a promoted ignition event.
The experiments provided insights into the combustion inhibition mechanisms in BAHXs used for producing pressurized oxygen. Data cited form a part of the technical basis for a Compressed Gas Association pamphlet entitled: “Safe Use of Brazed Aluminum Heat Exchangers for Producing Pressurized Oxygen”.
Repair Methods for Common Water Leaks at Operable Windows and Sliding Glass Doors
Authors: Beers PE , Smith WD 
Published: March 2009

In areas with high annual rainfall amounts, such as Florida, water leakage through operable windows and sliding glass doors is common, particularly at multistory applications. Although each leak is unique to the product and project, certain trends have developed. Investigations of water leakage at many projects throughout Florida, particularly multistory condominiums, have revealed several common water leak sources.
Observations during storms and field water tests have revealed three typical types of leaks that most frequently occur. Water percolation between operable members and the frame occurs during wind driven rain storms. Leakage through the sliding glass door track or window sill can occur any time water is present in the assembly. Leakage through perimeter sealants is usually induced during a wind driven rain, but can also occur if there is standing water next to the assembly.
Remedial Repair Leak Prevention in Porous Stone Faced Precast Panels — a Case Study Option
Authors: Flood RS 
Published: March 2009

A proposed leak repair scheme (tested per ASTM) could have significantly altered the aesthetic appearance of a 42 story, 600 ft. highrise office tower and adjacent lowrise auxiliary buildings in San Francisco, California. This case study describes an alternative leak repair scheme for the 1000+ panels of porous stone faced precast panel window wall, the objective of which was to retain the existing building appearance to the maximum extent feasible.
Water from panel perimeters, panel cracks, and stone anchor locations was leaking into the building around the windows and other areas. The remedial solution presented here focuses on the water in the cavity bounded by the porous stone faced pre-cast panel, the flush mounted aluminum and window frame, and the exterior and interior silicone sealant joints. The design methodology consisted of first minimizing water infiltration through the porous stone in a visually unobtrusive manner and second, channeling and controlling the remaining infiltrate to both the existing weep system and into newly created weeped jamb cavity reservoirs.
This option was implemented from the exterior, (using the building's window washing rig) on a mid-height in-situ panel, (selected for testing due to prior leak history). Readily available construction materials and methods were utilized. Upon completion, the repaired panel passed an extended duration ASTM E-1105-93 test. Substantially reducing water penetration into the composite panel and then controlling the remaining infiltrate, this ASTM tested leak repair option provided a functioning, cost competitive solution to the water intrusion problem without altering the existing building aesthetics.
Investigation and Repair of Leakage Problems in Recently Constructed Curtain Walls
Authors: Rutila DA 
Published: March 2009

Waterproofing problems with recently constructed curtain walls illustrate that some, well understood, principles of waterproofing continue to be violated during wall construction. The author finds that divided or fragmented responsibility for the design often leads to the lack of understanding of the waterproofing requirements. New problems are being invented/discovered during the design and construction of these curtain wall systems due to the lack of understanding of the design requirements. Design specifications, workmanship, and the management of construction all contribute to recent problems. This paper presents the author's experience investigating and repairing waterproofing problems in newly constructed curtain walls. The author presents examples of design, workmanship and construction management problems that contribute curtain wall leakage problems, and presents a summary of the repair design and implementation.
Designers must understand the difference between barrier (surface sealed) curtain wall systems and cavity wall systems. The design must reflect the selected concept(s) consistently through the details, and it must anticipate a reasonable level of workmanship. Contractors and construction managers contribute to waterproofing problems in modern curtain walls through their lack of understanding of the design principles and, therefore, their lack of knowledge of what is important to the waterproofing performance. When the managers and oversight professionals fail to understand the construction, their direction or lack of direction to the workers contribute to problems.
Quality Control Procedures to Prevent Water Leakage Through Windows
Authors: Beers PE , Smith WD 
Published: March 2009

Most water leakage problems through windows and doors are the result of installation errors. Even the best system designs cannot overcome poor installation techniques. Simple mistakes such as the omission of an internal seal can result in major water leakage that damages building interiors, upsets building occupants and often results in costly repairs.
By establishing a quality control procedure that specifically addresses windows and doors, common installation mistakes can be prevented. This paper will present a series of steps to follow before and during the construction process to insure proper installation of windows and other glazing products.