bluuebunny/crossref_metadata_2025 huggingface dataset:
Explosion Bonding of Titanium and Zirconium
Authors: Mancini WE
Published: March 2009

With today's high prices and severely corrosive environments, explosion bonding offers the strength and economy of one metal and the corrosion resistance of another. It is the only known process for obtaining a metallurgical bond between dissimilar metals such as titanium and steel, and it does not significantly after the properties of either metal. Clad plates have been hot and cold formed successfully by conventional shop techniques, and weld designs have been established for both compatible and non-compatible metal systems. Detaclad has found wide acceptance in many industries, including the petroleum, petrochemical, and chemical processing industries, where it meets specific requirements for high temperatures and pressures, vacuum service, thermal cycling, and high heat transfer.
Titanium for Mechanical Equipment in Industrial Corrosion Service
Authors: McMaster JA
Published: March 2009

Titanium usage in mechanical equipment for industrial corrosion service is increasing. The design and fabrication of this equipment requires special consideration to account for the fatigue properties and notch sensitivity of titanium, and maintainability of the finished equipment. Some weld metal properties, such as fatigue, are lower than similar properties for wrought products, and, therefore, welds should be properly contoured and located in low-stress areas.

Due to titanium's tendency for galling, threaded fasteners need thread coatings and are usually specified as loose fit. Using taper pins instead of straight pins and taking similar precautions also minimize the detrimental effects of titanium wear characteristics.
Fatigue Properties of Commercially Pure Titanium
Authors: Wardlaw TL , Hall JA
Published: March 2009

Room-temperature fatigue characteristics of ASTM Grade 2 titanium were investigated to provide information important to its design and life prediction capabilities. Load-controlled tension-tension fatigue tests were conducted on mill product strip materials under various loading conditions. Results indicated that the material had a significant fatigue life at stress levels above the corresponding yield strength and that neither prestraining nor the method of load application used showed a clear influence on fatigue performance. These characteristics may have useful implications in the design of industrial equipment. The influence of various surface-defect conditions on the fatigue properties is investigated and reported, and a comparison is made between the resultant runout stresses and common allowable design stresses.
Improving the Corrosion Resistance of Zirconium Weldments
Authors: Frechem BS , Morrison JG , Webster RT
Published: March 2009

Selective corrosion of zirconium Grade 702 weldments was observed in a process stream containing sulfuric acid at temperatures up to 150°C. Studies were conducted to determine the mechanism of the corrosion and to develop procedures for improving the corrosion resistance of the weldments.

Metallographic studies indicated that the dominant metallurgical factor affecting the selective corrosion is the presence and distribution of a second phase around the alpha grains. A simple heat treatment at 760 to 788°C disperses the second phase and significantly improves the corrosion resistance of the welds. The cooling rate was found to be critical only when temperatures are significantly higher than the recommended range.
Effects of Iron on the Corrosion Resistance of Titanium
Authors: Covington LC , Schutz RW
Published: March 2009

This paper presents the results of extensive laboratory tests and experience in industrial applications to explain the effects of iron on the corrosion resistance of titanium.

In the great majority of cases where titanium is being used in corrosive environments, the effect of iron at the levels normally found in unalloyed titanium (⋍0.1 percent) is insignificant and has not led to any problems. However, in some cases, high solid-solution iron levels have been blamed for premature failures due to pitting or hydrogen embrittlement. Tests conducted at TIMET, Henderson, Nev., suggest that solid-solution iron has little, if any, effect on susceptibility to pitting or hydrogen embrittlement.

Iron particles embedded in the surface of unalloyed titanium are very deleterious. They serve as initiation sites for pitting and also as entry points for hydrogen.

Ferric ions in the corrosive solution are beneficial and serve as an excellent passivating agent for titanium. Iron oxide deposits on the surface of titanium also have a passivating effect.

Galvanic coupling of titanium and iron can lead to accelerated corrosion of the iron and, in some environments, to hydrogen embrittlement of the titanium. The magnitude of the effect is dependent on surface area ratios and the characteristics of the environment. Titanium, however, is being widely used successfully in applications where galvanic coupling with iron exists, with comparatively few problems being reported.
Corrosion Resistance of Zirconium and Zirconium Alloys in Inorganic Acids and Alkalies
Authors: Knittel DR , Webster RT
Published: March 2009

Laboratory test data are given on the reactions of zirconium Grades R60702, R60704, and R60705 in sulfuric, phosphoric, nitric, hydrochloric, and hydrobromic acids and in caustics. At concentrations and temperatures in which zirconium has excellent resistance, the different grades corrode equivalently. Isocorrosion curves, taken from data obtained from a literature survey, are presented for sulfuric, phosphoric, nitric, and hydrochloric acids. Isocorrosion curves from data from the Teledyne Wah Chang Albany laboratory are presented for all the grades of zirconium with and without welds in sulfuric acid. The welds were found to be more susceptible to corrosion attack than the nonheated parent metal. The weld areas could be made less susceptible to attack in sulfuric acid by recrystallization heat treatment.
Trace Constituent Analysis for Metallic Systems: State of the Art
Authors: Javier-Son A
Published: March 2009

The search for the right analytical technique for a particular element or elements is an ongoing challenge to an analytical chemist. The choice of a method is based on the concentration level of the analyte element, the matrix, the accuracy, the precision and speed desired, and in many cases, the economics involved. Thanks to many zealous workers, there are volumes of procedures to choose from. Oftentimes the concentration level and the matrix involved narrow down the choice to a few or none. Modification of existing analytical procedures is commonplace. When the analyte element or elements exist in trace quantities, the matrix effect plays an even bigger role, and the applicable analytical procedures are very limited.

This paper is essentially a comparison of analytical techniques available for trace analysis of metallic constituents of metals, alloys, and geological samples. The detection limit, accuracy, precision, and speed of analysis are discussed. The review centers on bulk analysis. The microanalysis, or in situ, techniques are not explored. The critique covers light absorption, atomic absorption, atomic fluorescence, and X-ray fluorescence spectrometric methods and activation analysis. The field of trace analysis for metals is currently dominated by atomic absorption procedures, particularly those employing electrothermal atomization. The plasmas, particularly inductively coupled plasmas, have demonstrated an explosive growth over the last 5 years. Utilization in analytical techniques is increasing exponentially, particularly in the areas of atomic emission and atomic fluorescence.
A Comparison of the Capabilities of Atomic Absorption and Inductively Coupled Plasma Spectroscopy for the Analysis of Metallurgical Samples
Authors: Wallace GF
Published: March 2009

Three National Bureau of Standards aluminum brasses, Standard Reference Materials 1118, 1119, and 1120, were chosen as representative samples for a study comparing the capabilities of atomic absorption spectroscopy and inductively coupled plasma emission (ICP) spectroscopy for the determination of trace elements in metallurgical samples. The results for the determination of lead and phosphorus will be used as examples because these two elements reflect the unique capabilities of both techniques.

Phosphorus could be satisfactorily determined only by ICP, but great care was required in the choice of wavelength. The determination of lead is simple and straightforward by flame atomic absorption. The determination of lead by ICP was satisfactory but, again, the choice of wavelength was critical to the success of the analysis.

It was found to be most advantageous to use low ultraviolet (UV) wavelengths for the determination of both phosphorus and lead by ICP in order to avoid spectral overlaps by copper and other matrix components. Comparative emission spectral scans are shown for the various phosphorus and lead lines investigated. The severity of spectral interferences is compared for the UV and low UV wavelengths of phosphorus and lead.

This paper presents a comparison of the capabilities of atomic absorption spectroscopy and inductively coupled plasma emission spectroscopy for the analysis of aluminum brasses. Lead and phosphorus will be used as example elements. The points of comparison are the detection limits, the sample preparation requirements, and the interferences encountered.
Soil Surveys: Their Synthesis, Confidence Limits, and Utilization for Corrosion Assessment of Soil
Authors: Miller FP , Foss JE , Wolf DC
Published: March 2009

Organized efforts in soil classification and mapping in the United States began in 1899 as a cooperative research program of the U.S. Department of Agriculture and the state land-grant universities. Although the original objective of this program was oriented toward the soil as medium for plant growth, much of the data gathered by soil scientists over the last 50 years has been applied to nonagrarian land uses. Modern soil surveys have been prepared for nearly two thirds of the land area of the United States since 1955. This paper will discuss the data acquisition technique used in making soil surveys, the basis for the prediction of soil behavior from this information, the confidence limits of the information, and its application to corrosion engineering.
Replaceable Deep Groundbed Anode Materials
Authors: Tatum JF
Published: March 2009

The replaceable deep anode groundbed design is described in detail. Each component of the groundbed is shown along with complete details covering the installation thereof, with design factors and other parameters.

The various types of anode materials are described, and configurations of graphite anodes are discussed in detail with particular emphasis on the use of a center-tapped anode to prevent premature anode failure from end effect. Other anode materials are described, such as platinized titanium, platinized niobium, and platinum clad niobium. The use of platinum anode materials are covered in detail along with various anodically passive substrates.

Wire insulations are covered, such as high molecular weight polyethylene, and the dual jacketed insulations involving fluoropolymers along with their performance in downhole environments.

Calcined petroleum coke backfills are presented with information as to their resistivity and the various material specifications available.

The interference characteristics of deep groundbeds versus surface beds are shown in detail. The superiority of the deep groundbed in eliminating anodic interference is described, with data as to causes of cathodic interference.
A Consulting Engineer's Role in Power Plant Instrumentation for Measurement of High-Purity Water Quality
Authors: Hoppe TC
Published: March 2009

The reassessment of high-purity water is a never-ending process. Although the best available instrumentation is used, it is not always good enough when component failures are attributed to infinitesimal impurities in the water. This paper describes the necessary technology and personnel requirements for implementing a successful water quality control program.
Program for Steam Purity Monitoring: 1. Instrumentation and Sampling
Authors: Pensenstadler DF , Peterson SH , Bellows JC , Hickam WM
Published: March 2009

For the past 3 years the Westinghouse Electric Corp. has conducted a major program of instrument selection and development and sample analysis to monitor the steam turbine chemical environment and to determine the source of corrodant species that contribute to turbine blade corrosion.

This paper describes the development and application of a continuous on-line analyzer; a grab sample analysis program, utilizing state-of-the-art ion chromatography, to measure steam impurity concentration at various locations throughout the steam-water cycle; and the combination of these techniques, in the form of a total plant survey, to assess total power plant chemistry.

The significance and usefulness of continuously monitoring parameters such as sodium, dissolved oxygen, conductivities, and chloride is discussed, as are the validity of the sampling procedures, the utility of a nozzle to extract steam, and the strengths and weaknesses of ion chromatographic grab sample analyses. Finally, the implementation of a data acquisition system on the continuous analyzer, to handle the ever-increasing amount of information being generated by seven of these field systems, is reviewed.
In-Plant System for Continuous Low-Level Ion Measurement in Steam-Producing Water
Authors: Simpson JL , Robles MN , Passell TO
Published: March 2009

This paper describes the development of an on-line analytical instrument to measure selected anions and cations over the sub-parts-per-billion to several partsper-million concentration range. The system has been designed and is being installed in an electrical generating power plant. Laboratory evaluations and limited in-plant experiences will be discussed regarding measurements of nonhydrolyzable anions and cations, transition metal ions, and organic acids. The system will accommodate multiple sample line inputs with computer-controlled options to provide sample averaging, automated sample point selection, and system standardization and calibration. The data acquisition capabilities, including storage and report generation, will also be addressed.
Zero: The Unreachable Goal
Authors: Fisher SA
Published: March 2009

A review of the progress that has been made in improving the quality of high-purity water during the 40 plus years of existence of ASTM Committee D-19 on Water shows that the steps downward in impurity levels are impressive but the goal of zero impurities is still a long way off. We have reached the limits of the use of electrical conductivity as the sole monitor of further improvement in industrial water quality. If still lower impurity levels are sought, their precise nature must be elucidated, and they must be monitored as specific entities.
Description and Evaluation of a Continuous Sample Water Evaporator
Authors: Elmiger SJ , Mravich NJ , Stauffer CC
Published: March 2009

Current power industry requirements place increasing emphasis on water and steam purity. Many of the contaminants present in plant systems exist at levels below the detection limits of available analytical methods. Evaporation of large volumes of water in a controlled environment provides a means of increasing the concentration of contaminants to a level that can be readily analyzed by current methodology. Since the continuous sample evaporator described in ASTM Tests for Particulate and Dissolved Matter in Water (D 1888-78) is no longer marketed, an improved version of the evaporator was designed, fabricated, and tested for low-level contaminant recovery.

The new instrument is capable of evaporating solutions from sample bottles or a sample line at rates approaching 500 cm3/h. The samples are concentrated in precleaned platinum dishes. A detailed description of the new evaporators and their operation is discussed.

Performance tests were conducted on both laboratory and field samples to define the limitations of the evaporation process for trace chemical analysis. These analyses included calcium, magnesium, iron, copper, potassium, sodium, chromium, nickel, manganese, zinc, lead, aluminum, silica, sulfate, chloride, phosphate, and nitrate. The laboratory studies showed that the evaporators were capable of chemical species recovery generally within ±20 percent of the absolute amount of synthetic species added. Evaporation and analyses of field samples obtained from operating power plants compared favorably with other concentrating techniques for most species. However, there are certain contaminants which cannot be determined accurately with current evaporation techniques and may require analysis by other available methods.
Experimental Observation of Crack Velocity and Crack Front Shape Effects in Double-Torsion Fracture Mechanics Tests
Authors: Michalske TA , Singh M , Frechette VD
Published: March 2009

The double-torsion test configuration has been used to obtain crack growth information for a variety of materials. Recently critical reviews have suggested that certain assumptions used in the interpretation of double-torsion data are of questionable validity.

This paper presents experimental data for crack growth in glass specimens loaded in the double-torsion test configuration. The constant displacement rate technique was used to propagate cracks and velocity was measured continuously by superimposing a tuned-frequency sonic signal during cracking. The crack velocity profile as a function of position along the crack front was determined. The crack velocity at the tensile surface was measured as a function of crack length at constant load and the crack front shape was observed for various crack lengths.
Determination of High-Temperature KI-v Data for Si-Al-O-N Ceramics
Authors: Lewis MH , Karunaratne BSB
Published: March 2009

A “double-torsion” test jig for operation in vacuum or a selected gas atmosphere at temperatures up to 1500°C is described. The jig has been used to determine stress intensity (KI)-crack velocity (v) relationships for single-phase β' Si-Al-O-N ceramics which have been hot-pressed with different “impurity” densification aids and which have received “post-sintering” heat treatments.

The KI-v data have been calculated using three testing procedures; (a) for high crack velocities (10−2 to 10−4 ms−1) from the rate of load relaxation, (b) for intermediate velocities from the “constant displacement rate” technique and, (c) for low velocities (10−6 to 10−10 ms−1) from direct measurements of crack velocity on sequential application of a constant load. A procedure for a “machine-relaxation” correction for technique (a), evaluation of the deviation in the “constant KI” assumption with crack length and the sensitivity to specimen thickness, is described.

The data can be fitted to a relationship of the form v = constant KIn over a wide range of crack velocity with excellent continuity in data obtained from the different techniques and good agreement with isolated values from “notched-beam” tests.

Marked variation in the stress-intensity exponent n which occurs for ceramics with different sintering aids may be correlated with differing susceptibility to subcritical crack growth by means of interlinkage of creep cavities and, in turn, on grain boundary structure. A progressive change in the v-KI relationship with heat treatment in “noncavitating” ceramics is discussed in terms of current theories for diffusive intergranular crack growth.

The consistency of these data, sensitivity to change in grain-boundary structure, and a correlation with creep behavior indicate that double-torsion tests on small ceramic specimens at elevated temperatures may be used with confidence in determining KI-v relationships, either for failure prediction or in distinguishing between different slow-crack growth mechanisms.
Extension of the Compliance and Stress Intensity Formulas for the Single Edge Crack Round Bar in Bending
Authors: Ouchterlony F
Published: March 2009

The compliance and stress intensity formulas for the solid single edge crack round bar in bending (SECRBB) specimen with a support span to diameter ratio S/D = 3.33 are extended to cover notch depth ratios 0 ≤ a/D < 0.6, an arbitrary Poisson's ratio, and a slight variation in S/D. The work is based on a precise and reliable measurement of the load point displacement on notched rock cores of Ekeberg marble. The measuring method virtually eliminates friction and twisting effects as well as nonlinear contact and crushing phenomena. It yields an accurate value of the Young's modulus.

The experimental results give the extension of the formulas which are used for a thorough fracture mechanics analysis of the SECRBB specimen. The matters considered are the crack growth stability, the secant offset at 2 percent apparent crack growth, and the logarithmic derivative relating the J-integral to work done. Hence a basis is laid for correct linear and nonlinear fracture toughness measurements with the SECRBB specimen.
Measurement of the Hydraulic Conductivity of Fine-Grained Soils
Authors: Olson RE , Daniel DE
Published: March 2009

The purpose of this paper is to review the state of the art in the measurement of hydraulic conductivity of fine-grained soils. Both field and laboratory tests for saturated and partially saturated soils are considered.

For saturated soils, field tests are to be preferred because they permeate a larger volume of soil, thus taking into account the effects of macrostructure better than laboratory tests. Field tests are generally best performed by using a cylindrical piezometer tip, installed by methods that minimize disturbance, and measuring flow under a constant head. Laboratory tests offer the advantage of economy. Laboratory specimens should be as large as practical and should be oriented to produce flow in the direction of maximum hydraulic conductivity. The permeant should be a fluid similar to that encountered in the field. Without proper experimental technique, the conductivity measured in the laboratory may differ from the field value by several orders of magnitude.

Field tests for unsaturated soils are not well developed and can only be recommended for cases where water will be ponded on the surface of a site. The most versatile laboratory techniques are the instantaneous profile method using tensiometric or psychrometric probes, and the pressure plate outflow method. The best method to use depends on the soil suction expected in the field.
The du Pont F21 149°C (300°F) Accelerated Stability Test
Authors: Henry CP
Published: March 2009

The du Pont F21 149°C (300°F) Accelerated Stability Test has been used for many years to monitor stability properties of distillate fuels. The test (or variations of it) is the most commonly used in the petroleum industry because, of the many tests available, it is easiest to carry out. A small fuel sample is heated to 149°C (300°F) for 90 min or more, cooled, and filtered; degradation is qualitatively determined by visual or instrumental evaluation of the filter pad—without the need for gravimetric procedures. In our laboratory it is usually the first of several tests to evaluate fuel stability; results guide further work. The test is also used to monitor fuel stability during production, distribution, and storage.

Variations, refinements, applications, and limitations of the test are discussed. Severity is modified by varying the 149°C (300°F) aging period from 90 min to 4½ h. Sensitivity is varied by changing the porosity of the filter paper. Test results are precisely rated by measuring filter pad light reflection. The reproducibility of the test is considered, along with factors which affect results.

Data are presented which show the relationship of test results with actual long-term storage stability of fuels.
Microbial Contamination of Ship Fuels
Authors: Neihof RA , Klemme DE , Patouillet CE , Hannan PJ
Published: March 2009

A laboratory evaluation has been made of water-soluble biocides which might be effective in controlling microbial contamination in water-compensated fuel storage tanks on naval ships. Higher concentrations of biocides were generally required for control of sulfate-reducing bacteria in steel drums simulating ships' tanks than in test-tube scale assays. At least tenfold higher concentrations were necessary when biocide additions were made after, rather than before, bacterial growth had developed extensively. A mercaptopyridine biocide was effective at the lowest concentration followed by methylene bisthiocyanate and a triazine derivative; an organoboron compound was comparatively ineffective.

Attention has also been given to the possible environmental impact of discharging biocide-treated water. An algal assay has been used to study the loss in toxicity of candidate biocides in seawater solution on exposure to sunlight. The mercaptopyridine biocide was particularly susceptible to photodegradation. Thus it may be possible to control microbial contamination indefinitely in a dark fuel tank with a biocide which photodegrades to nontoxic products when discharged into sunlit surface waters.
Microbiological Contamination of Fuels During Storage
Authors: Littmann ES
Published: March 2009

Microorganism growth during hydrocarbon storage is a well-recognized problem. The most easily detected problem is fuel filter plugging, particularly in aviation fuels. Other problems include degradation of hydrocarbon quality, corrosion of storage tanks, and concentration of hazardous or toxic growth by-products in the water associated with the storage.

Particular problems and the growth of the microorganisms creating them are discussed. The discussion also includes methods for detection and quantitation of the troublesome organisms and philosophies for control of the microorganism growth.
Surface Materials and Properties Related to Seasonal Variations in Skid Resistance
Authors: Hill BJ , Henry JJ
Published: March 2009

A three-year research program was initiated in 1978 at the Pennsylvania Transportation Institute by the U.S. Department of Transportation to investigate possible causes for seasonal and short-term skid resistance variations. The primary objective is to determine the parameters which can be used to predict the influence of seasonal and short-term effects. This paper is concerned with the material parameters influencing the long-term seasonal variations.

Data are analyzed from 21 test surfaces in State College, Pennsylvania and 10 test surfaces in Tennessee and North Carolina. The data include skid resistance measurements according to the ASTM Test for Skid Resistance of Paved Surfaces Using a Full-Scale Tire (E 274-79), British Pendulum Number measurements, calculated percent normalized skid number gradient, and average daily traffic volumes. An exponential curve is fitted to the skid number data for the asphalt pavements, while a linear relationship best fits the data for portland cement concrete surfaces. The coefficients of the resulting seasonal variation curves are regressed against pavement and traffic parameters to provide predictors for the long-term effects. Significant predictors are found to be British Pendulum Number and average daily traffic. Further predictors are suggested by the results of a pavement polishing experiment carried out on the 21 Pennsylvania test surfaces. Good agreement is observed between the two sets of test data.
Frictional Performance of Pavements and Estimates of Accident Probability
Authors: Burchett JL , Rizenbergs RL
Published: March 2009

Objectives of this study were to evaluate standard and experimental surfaces throughout Kentucky in terms of skid resistance and effects of traffic, and to provide criteria for judging suitability of these surfaces to satisfy requirements for skid resistance and economics. The effects of traffic were quantified by regression analysis and scatter of data. Criteria included an estimate of accident risks, effects of speed on skid resistance, and seasonal variations in skid resistance.

Pavements on low volume roads (less than 1000 vehicles per day) maintained adequate skid resistances. Open-graded friction courses, with the possible exception of sections using phosphate slag aggregate, maintained adequate skid resistance to meet design requirements. The adequacy of other pavements may be judged from the criteria provided herein.

Estimates of accident reduction were made by combining the relationship between skid numbers and accidents with the distribution of skid numbers for each pavement type. Those reductions were used to calculate benefits that, along with costs of overlay, were used to determine benefit-cost ratios. Benefits exceeded costs for roads having annual average daily traffic (AADT) greater than 750, 2500, and 5000 and skid numbers (SN) less than 24, 30, and 35, respectively.
Influence of Tread Wear Irregularity on Wet Friction Performance of Tires
Authors: Williams AR , Evans MS
Published: March 2009

The reduction in wet skidding resistance with reduced tire tread pattern depth on road surfaces possessing low macrotexture is well understood. With the dominance of radial tire construction, with its inherently higher abrasion resistance, automobile tires are often observed to be removed from the vehicle in an irregularly worn condition rather than the regularly worn condition that has been the subject of previous work. This paper describes tire measurements using indoor and outdoor test facilities for a range of tires that includes the most common irregularly worn conditions: those of two-shoulder and one-shoulder wear, center wear, and the increasingly less observed uniform wear. The correlation between test methods is discussed and observed differences in tire friction characteristics with wear type explained. The stability of the vehicle under low friction conditions is an additional factor in the accident mode situation; the influence on vehicle stability due to irregular tire wear and that provoked by changing the position of part-worn tires on the vehicle is also discussed.
Tire Traction Testing in Adverse Environments
Authors: Janowski WR
Published: March 2009

Traction testing of passenger car and truck tires in adverse environments (snow, ice, mud, and sand) has become an increasingly important segment of most new tire development programs. This increased emphasis is due to the continued refinement of the all-season design, consumer desires for more effective on- and off-road recreational vehicle tires, and the greater amounts of test documentation required for government agencies. This paper reviews testing and engineering techniques currently used in traction testing in adverse environments and discusses problems specifically related to the traction testing of small, lightly loaded tires under winter conditions. In addition, overall test course preparation is discussed, including the increasingly important concept of reconditioning of snow test surfaces to overcome unfavorable weather conditions. Typical instrumentation and data acquisition systems are presented. The paper concludes with a review of current industry efforts to standardize test methodology in the winter environment, and suggestions for further improving tests in all of the adverse environments.
An Interactive Tire-Fluid Model for Dynamic Hydroplaning
Authors: Browne AL , Whicker D
Published: March 2009

An interactive tire-fluid model has been developed to serve as an aid in understanding dynamic hydroplaning of pneumatic tires. Dynamic hydroplaning occurs when the amount of fluid encountered by the tire exceeds the drainage capacity of the footprint region. The tire is completely separated from the pavement by a fluid film.

Important advances in the present model are the automatic generation both of tire surface deformation in the contact region and of vertical axle displacement, both being due principally to fluid inertial forces. Present forms of the two major analysis modules comprising this model—tire deformation and fluid flow—are described in detail. Required experimental inputs including velocity, water film depth, and tire cross-sectional geometry are indicated. A description is then given of how these modules and the inputs they require are combined to form an interactive model. Examples are provided demonstrating the accuracy of the model's predictive capability. The effects of both speed and load on tire deformation in the footprint region and on axle height as predicted by the model are seen to be in agreement in trend with experimentally determined results.
Pavement Design and Controls for Minimizing Automotive Hydroplaning and Increasing Traction
Authors: Balmer GG , Gallaway BM
Published: March 2009

The authors discuss test results and analyses of tire hydroplaning, skid resistance, and other tire-pavement interactions. They address roadway and vehicle operator controls for mitigating hydroplaning and improving highway safety.

The conclusions are based on analyses of simulation, laboratory, and full-scale tests. Pavement cross slope, texture, rut depth, pavement wear, surface drainage, drainage-path length, precipitation intensity and duration, tire inflation, tread-pattern depth, tire construction, and vehicle traveling speed influence hydroplaning tendencies and vehicle control.

Other factors considered are tire rolling resistance, vehicle fuel consumption, noise, splash and spray, and headlight glare.

These results are applicable to highway pavement design, construction, and rehabilitation; tire construction; and vehicle operation.
Comparison of the Friction Performance of a Passenger Car Tire and the ASTM Standard Test Tires
Authors: Henry JJ
Published: March 2009

Tire-pavement friction data were obtained for three tires using a pavement friction tester conforming to ASTM Method E 274. The ribbed E 501 test tire, the blank E 524 test tire, and a commercial passenger car tire of similar size and construction were tested. When new and slightly worn, the passenger car tire produces higher friction under the E 274 test conditions than does the ribbed tire. For greater water film thicknesses it is shown that the slightly worn passenger car tires produce friction levels between those of the two standard test tires.

Braking distance tests were performed with the slightly worn passenger car tires on a diagonally braked vehicle in accordance with ASTM Method E 503. The results are compared with a prediction of braking distance calculated from longitudinal friction data obtained with a pavement friction tester operated over the same site under the same water film conditions. The calculations provide a conservative estimate of braking distance for use in estimating stopping sight distance.
Tire Rolling Noise in Dry and Wet Conditions on Pavement Surfaces of Different Skid Resistance
Authors: Liedl W , Köhler E
Published: March 2009

When investigating tire rolling noise it is imperative that driving safety must not be neglected. For this reason, noise measurements with a single-wheel measuring trailer on very different dry and wet road surfaces are accompanied by skid coefficient measurements in wet conditions using the Stuttgart friction meter. Included in the investigations are a large number of tires with standard and special tread patterns (steel-belted tires for passenger cars). The hydroplaning behavior of these tires is additionally examined by traction coefficient measurements in wet conditions on an inside drum tester. The results indicate that, particularly on a dry road surface, the often-quoted conflict of goals between lowering tire rolling noise on the one hand and reducing driving safety on the other does not exist since it is possible for comparatively quiet road surfaces to have excellent grip in the wet. Furthermore, the results on the inside drum tester show when compared with the on-the-road noise measurements that there is a distinct correlation between improving the hydroplaning behavior and reducing the rolling noise of the tires investigated.
Traction Modifications Resulting from Test-Induced Treadwear
Authors: Bernard JE , Ervin RD , Segel L
Published: March 2009

Measurements have shown that the traction performance of pneumatic tires can be profoundly influenced by wear which accrues during the testing process. These findings indicate that changes can occur in the shear forces generated at both high and low slip angles as a consequence of testing at high angular slip. These performance changes are capable of significantly altering a vehicle's directional properties and thus suggest that data from tests involving high rates of test wear be interpreted with special caution.

The paper reviews and expands upon the basic findings through presentation of data taken on laboratory and mobile tire traction dynamometers and from vehicle tests for both passenger car tires and truck tires.
Prediction of Tire-Road Friction from Surface Texture and Tread Rubber Properties
Authors: Yandell WO , Taneerananon P , Zankin V
Published: March 2009

Over the past decade the senior author and his students have been working on a purely theoretical technique for predicting tire-road friction. It is based on a postulated model of the tire friction mechanism and hence relies on road surface texture measurements and on road surface water film thickness plus the laboratory-measured elastic and damping properties of the tire tread rubber. The method has evolved into a more mathematically complex procedure after validation tests on a number of roads. Each additional refinement has made the method more accurate but possibly not, at this stage, as practical as simpler, partly empirical methods that recently have been developed elsewhere. The paper, however, which is presented in simple terms, demonstrates that the moderate use of tread rubber temperature categories will enable the sideways force or locked-wheel friction to be predicted accurately for any speed, wetting condition, or tread rubber properties for bald and patterned tires. In the event of the technique being finally validated, it could be largely automated for simplicity.
Void Formation and Transport During Composite Laminate Processing: An Initial Model Framework
Authors: Kardos JL , Duduković MP , McKague EL , Lehman MW
Published: March 2009

The fabrication of a high-performance structural composite laminate, such as a 64-ply graphite/epoxy system, currently suffers from the occurrence of voids in the final part. This very complex process involves simultaneous heat, mass, and energy transfer along with chemical reaction in a multiphase system with time-dependent material properties and boundary conditions. This study presents an approach to modeling void formation, stabilization, and transport in this complex system; the approach utilizes dimensional analysis as well as an analogy between void transport in composites and removal of oil from sand by water flooding. The general framework of the model is presented and some initial results involving void stabilization by water vapor are described.
Characterization of Some Solvent-Resistant Thermoplastic Matrix Composites
Authors: Kays AO , Hunter JD
Published: March 2009

The chemical, thermal, mechanical, and solvent-resistant characteristics of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), and polyether ether ketone (PEEK) have been investigated. These studies employed Fourier Transform Infrared Analysis (FTIR), differential scanning calorimetry (DSC), and X-ray diffraction to characterize the chemical, thermal, and crystalline nature of the neat resins. Tension tests of their composites were also conducted to determine mechanical property behavior both initially and after exposure to humidity and solvents.
Effect of Microstructure on the Mechanical Behavior of Sheet Molding Compound Composites
Authors: Kline RA
Published: March 2009

Mechanisms for damage initiation and growth in sheet molding compound composites were studied with several nondestructive testing techniques. Damage was found to initiate by matrix cracking at relatively low stress levels. Fiber bundles were found to be effective in impeding the progress of these matrix cracks. At higher stress levels, however, the fiber bundles can no longer resist matrix crack propagation and specimen fracture occurs principally by fiber-matrix debonding. Specimen inhomogeneity was found to play an important role in these materials, with large variability in local fiber content being observed. Resin-rich regions of the specimens were identified as being likely failure sites.
Characterization of Quick-Cure and Vacuum-Bag Cure Composites
Authors: Gleason DJ
Published: March 2009

Current processing techniques for graphite/epoxy (Gr/Ep) composites require use of autoclaves. Because the autoclave is a major capital investment, materials that either eliminate the need for the autoclave or shorten autoclave cure times could reduce fabrication costs. The object of this study was to investigate composite materials that had short cure times and that were cured with vacuum-bag pressure only.

Two of the materials investigated were Hexcel HX565/T300 and Celanese diallyl phthalate (DAP)/C6000. Basic mechanical properties were determined initially for these systems. Because these initial results looked promising, the materials were further evaluated. These investigations included processing-time studies and fabrication and testing of a configured part. For the processing-time studies, viscosity profiles and interlaminar shear strengths were determined for several different cure cycles. The results did not indicate any advantage in altering the fast heat-up rate and short-cure-time cure cycle. The configured part evaluated was a hat-stiffened curved panel. Autoclave and vacuum-bag cured parts were tested in compression, in the post-buckling regime, and compared with a Gr/Ep system. The results from all tests indicate that the mechanical properties for these quick-cure and vacuum-bag cure systems are inferior to current Gr/Ep systems. However, the quick-cure and vacuum-bag cure materials might be cost effective in applications where minimum gage requirements make conventional Gr/Ep less efficient.
Determination of Tensile Strength of Soils by Unconfined-Penetration Test
Authors: Fang HY , Fernandez J
Published: March 2009

This paper describes the factors affecting the test procedures and methods for preparation of test specimens for determination of tensile strength of soils by unconfined-penetration (UP) method. Correlation of tensile strength with other soil constants and strength parameters, such as Atterberg limits, activity, toughness index, unconfined compressive strength, cohesion, and friction angle, are presented. Theoretical explanations of this method and the conventional split-tension test by use of the limit analysis concept are discussed.
Effect of End Membrane Thickness on the Strength of “Frictionless” Cap and Base Tests
Authors: Norris GM
Published: March 2009

Considerable effort has been devoted to assessing differences in behavior between the conventional triaxial test (H = 2 to 2½ D) with end restraint and the “frictionless” cap and base test (H = D) with greased end membranes. While it is generally acknowledged that a minimal end membrane thickness is required for a frictionless test on sand to prevent effective bearing of particles through end membranes and into cap and base, it has not been recognized that beyond some optimal thickness a Poisson's effect dominates, causing an artificial reduction in sand strength. Therefore sand strength decreases gradually as end membrane thickness increases, first as end restraint is reduced and then as the Poisson's effect takes over. With the aid of stacks of multiple greased membranes, the optimum end membrane thickness (thickness where end restraint and Poisson's effect are near minimum values and counterbalance each other) can be established and the Poisson's effect avoided. Given that optimum end membrane thickness for the frictionless test on sand varies with sample height and confining pressure as well as particle size, and that the frictionless test requires correction or central measurement of sample deformation (overall deformation includes sand, membranes, extruding grease, etc.), the conventional test is preferable whenever feasible. Certainly the conventional test can be used when strength alone is required, since it yields a strength comparable to that of the frictionless test with optimum end membrane thickness on sand.
The Critical-State Pore Pressure Parameter from Consolidated-Undrained Shear Tests
Authors: Mayne PW , Swanson PG
Published: March 2009

The results of isotropic and anisotropic consolidated-undrained shear tests (CIU, CK0, U) are used to determine the critical-state pore pressure parameter (Λo). The relative advantages of using the critical-state parameter (Λo) over Skempton's pore pressure parameter (A) and Henkel's parameter (a) are discussed. The effects of over-consolidation ratio (OCR) and initial stress state (K0) on both Henkel's and Skempton's pore pressure parameters can significantly alter effective stress predictions of undrained strength. The critical-state parameter is independent of OCR, K0, and level of shear to failure, thus requiring only two basic soil constants in order to predict undrained strength: (1) the effective stress friction angle (φ'), and (2) the critical-state pore pressure parameter (Λo).

An “extended” critical-state model is developed using the equivalent pressure concept for overconsolidated states. The method then provides a simple analytical representation of undrained stress-strain behavior and pore pressure response for clays with different values of OCR. One additional soil constant (Cc: the virgin compression index) is required in order to model stress-strain behavior.

The validity of the critical-state theory is substantiated by data from over ninety different clay and silt soils reported in the geotechnical literature. Furthermore, the critical-state concepts are shown to encompass both total stress and effective stress methods under one unified theory.
Concepts for a Shear-Normal Gage to Estimate In Situ Soil Strength and Strength Angle
Authors: McNeill RL , Green SL
Published: March 2009

Concepts are developed whereby the in situ shear strength (S) and the effective soil strength angle (φ') at large strains can be calculated from the readings of a combined shear/normal-stress gage mounted on the face of a rough penetrator. It is possible to calculate S and φ' even if interface friction is the mechanism of failure, unless that friction is local to the gage face. For the case of local friction, the method yields only the interface friction angle δ. Experimental results are encouraging, and the method is being studied for application to a deepwater wire-line device for in situ determinations of S and φ'.
Limitations of Direct Simple Shear Test Devices
Authors: La Rochelle P
Published: March 2009

The Direct Simple Shear (DSS) test devices have a major fundamental defect which has been recognized for over 40 years. In this paper, the limitations of the DSS test are emphasized by test results obtained on a highly sensitive and brittle clay of Eastern Canada. The DSS devices are no real improvement over the direct shear devices and the value of the triaxial test is far superior.
A Qualitative Stress-Strain (Time) Model for Soft Clays
Authors: Crooks JHA
Published: March 2009

Successful analytical modeling of the behavior of soils requires that these models incorporate the significant factors which control real soil behavior. To illustrate this point, a qualitative stress-strain (time) model for understanding the behavior of soft clays is described. The major feature of the model is the yield envelope—the locus of effective stress states in q–p stress space which result in a change from small strain response to loading to a large strain response. The model is used to provide a qualitative understanding of the behavior of soft clays subjected to embankment loading at two sites. Various features of the soil model, such as normalization of the yield envelope with respect to preconsolidation pressure together with use of strain energy as a parameter to define yield, are also discussed in relation to analytical formulation of the model.