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PURPOSE The aim of the study was the development and proof testing of an arthroscopic dorsal ligament plasty using a hydrojet knife in the pig TMJ before using in man. MATERIAL AND METHODS The dorsal TMJ ligament of ten pigs (country breed) was irradiated with a hydrojet (diameter 120 microm, working pressure 90 bar) under arthroscopic visualization. Postoperatively the pigs were controlled for 10 weeks before sacrifice. The isolated TMJs were examined by light microscope and the results compared with untreated pig TMJs. The flows over our arthroscopic instruments were measured to exclude the possibility of damaging surrounding structures by pressure. RESULTS Clinically we found no complications after arthroscopic surgery. Food intake was normal and development of body weight according to the food offered. Histology revealed tissue reorganization connected with increased collagen fibre production. Our calculations showed no pressure higher than 1000 mm water column in the TMJ under our working conditions. CONCLUSIONS The idea of arthroscopic dorsal ligament plasty using a hydrojet works in pig TMJs. Experience in TMJ arthroscopy is necessary. We found no danger of barotrauma under arthroscopy with the hydrojet. The results indicate dorsal ligament shortening by development of scar formations. In our opinion the method can be used for the therapy of dorsal ligament elongation and disk displacements in the TMJ of man.

Summary Purchase of anything that costs thousands or tens of thousands of dollars and which can have direct impact on the health of your business is worth doing to the best of your ability. Cleaning equipment fulfills that criterion. You can buy the right equipment for your application — that which meets your quality and productivity needs. You can also not do so, and risk failure. The difference is in your approach to the situation. Your approach should be that stated by writers more literate and technologists more knowledgeable than this one: figure out what are your needs and meet them. Said another way, don't let the normal issues of supplier competitiveness, price, proof testing, or desire to have or avoid uniqueness sidetrack you from this mission. Purchase of equipment is simple: buy what you need.

Seismic ties are the connecting devices installed between a boiler and its supporting structure in thermal power plants. The seismic ties are made of steel and allowed to be used in the elasto-plastic deformation region in order to reduce the seismic response of the boiler structure. This paper deals with an anti vibration performance proof test for an optimized stiffness distribution of elasto-plastic joint elements for boiler structures using a down-scaled boiler structure model on a large shaking table.

In prosthetic applications, the reliability of implant materials over a period of thirty years is absolutely essential. Calculation of the lifetimes of alumina ceramic heads is generally made on the basis of experimental fatigue and slow crack growth tests using finite element analysis. This investigation is aimed at understanding the fatigue behaviour of fine-grained alumina heads of hip joints. The service conditions of cyclic stress experienced by hip joints during walking are used in evaluating the fatigue behaviour of alumina femoral heads. These femoral heads have successfully withstood 107 cycles at a maximum walking stress of 17.2 kN, which is equivalent to a body weight of 400 kg. The femoral heads did not exhibit any sub-critical crack growth at the maximum walking load of 10kN, indicating the quasi-infinite performance life in patients up to a body weight of 250 kg. The details of proof testing designed for evaluating the performance of femoral heads over 40 years are also presented.

Purpose The subject area of the assignment is accounting education and testing techniques. Methodology/approach This paper details an effective method to create individualized assignments and testing materials. Using a spreadsheet (Microsoft Excel), the creation of the unique assignments and answer keys can be semi-automated to reduce the grading difficulties of unique assignments. Findings Because students are using a unique data set for each assignment, the students are able to more effectively engage in student to student teaching. This process of unique assignments allows students to collaborate without fear that a single student would provide the answers. As tax laws (e.g., credit and deduction phase-outs, tax rates, and dependents) change depending on the level of income and other factors, an individualized test is ideal in a taxation course. Practical implications The unique assignments allow instructors to create markedly different scenarios for each student. Using this testing method requires that the student thoroughly understands the conceptual processes as the questions cannot be predicted. A list of supplementary materials is included, covering sample questions, conversion to codes, and sample assignment questions. Originality/value This technique creates opportunities for students to have unique assignments encouraging student to student teaching and can be applied to assignments in any accounting course (undergraduate and graduate). This testing method has been used in Intermediate I and II, Individual Taxation, and Corporate Taxation.

International audience; This paper proposes a holistic approach to model the Safety Instrumented Systems (SIS). The model is based on Switching Markov Chain and integrates several parameters like Common Cause Failure, Imperfect Proof testing, partial proof testing, etc. The basic concepts of Switching Markov Chain applied to reliability analysis are introduced and a model to compute the unavailability for a case study is presented. The proposed Switching Markov Chain allows us to assess the effect of each parameter on the SIS performance. The proposed method ensures the relevance of the results.

Seismic ties are connecting devices installed between boiler and it's supporting structure in thermal power plants. The seismic ties are made of steel and allowed to be used in the elasto-plastic deformation region in order to reduce the seismic response of the boiler structure. This paper deals with proof test of anti-vibration effect due to the elasto-plastic bahavior of the seismic ties using scaled boiler structure model, which has scaled seismic tie models as large as possible, on a large shaking table. We developed "Dual Mass Approximation Method" for the boiler structure in order to design it's scaled model.

The CTOD design curve of WES 2805-1997 is widely used for the flaw evaluation from fitness for purpose view points. In the design curve, welding residual stresses are treated as constant magnitude strains or CTODs, therefore residual stress effects on brittle fracture strength are overestimated in low fracture toughness regions. In this study, evaluation methods of effect of previous loads, such as welding residual stress and preload by proof test etc., on the brittle fracture strength are ivestigated and a modification of the CTOD design curve method is proposed. It is confirmed that residual stress effects on brittle fracture strength in a low fracture toughness region are fairly well estimated using a proposed method by comparing estimated brittle fracture strength with experimental one.

Examination of proof test data for new (not previously installed) stainless steel (SS) trim spring operated pressure relief valves (SOPRV) reveals that adhesions form between the seat and disk in about 46% of all such SOPRV. The forces needed to overcome these adhesions can be sufficiently large to cause the SOPRV to fail its proof test (FPT) prior to installation. Furthermore, a significant percentage of SOPRV which are found to FPT are also found to “fail to open” (FTO) meaning they would not relief excess pressure in the event of an overpressure event. The cases where adhesions result in FTO or FPT appear to be confined to SOPRV with diameters less than or equal to 1 in. and set pressures less than 150 pounds per square inch gauge (psig) and the FTO are estimated to occur in 0.31% to 2.00% of this subpopulation of SS trim SOPRV. The reliability and safety implications of these finding for end users who do not perform pre-installation testing of SOPRV are discussed.

Purpose: to reveal distinctions in some psychophysiological characteristics of students with various level of motion activity. Materials and methods: the research was conducted on the basis of Kharkov national medical university. 312 students are investigated. Methods were used: questioning and pedagogical supervision. Results: the reliable distinctions are observed in the speed of processing of visual information at proof test at young men, and also in the subjective estimation by students of their health, activity and general self-appraisal in the analysis of psychophysiological indicators at students with the various level of motion activity. Conclusions: the reliable connection of the level of motion activity with a self-appraisal by students of their functional state is established., Цель: выявить различия в некоторых психофизиологических характеристиках студентов с различным уровнем двигательной активности. Материалы и методы: исследование проводилось на базе Харьковского национального медицинского университета. Исследовано 312 студентов. Использованы методы: анкетирования и педагогического наблюдения. Результаты: при анализе психофизиологических показателей у студентов с различным уровнем двигательной активности достоверные различия наблюдали в скорости переработки зрительной информации при корректурной пробе у юношей, а также в субъективной оценке студентами своего самочувствия, активности и общей самооценки. Выводы: установлена достоверная связь уровня двигательной активности с самооценкой студентами своего функционального состояния., Мета: виявити відмінності в деяких психофізіологічних характеристиках студентів з різним рівнем рухової активності. Матеріали і методи: дослідження проводилося на базі Харківського національного медичного університету. Досліджено 312 студентів. Результати: при аналізі психофізіологічних показників у студентів з різним рівнем рухової активності достовірні відмінності спостерігали в швидкості переробки зорової інформації при коректурної пробі у юнаків, а також в суб'єктивній оцінці студентами свого самопочуття, активності і загальної самооцінки. Висновки: встановлено достовірний зв'язок рівня рухової активності з самооцінкою студентами свого функціонального стану.

The safety integrity level (SIL) of equipment used in safety instrumented functions is determined by the average probability of failure on demand (PFDavg) computed at the time of periodic inspection and maintenance, i.e., the time of proof testing. The computation of PFDavg is generally based solely on predictions or estimates of the assumed constant failure rate of the equipment. However, PFDavg is also affected by maintenance actions (or lack thereof) taken by the end user. This paper shows how maintenance actions can affect the PFDavg of spring operated pressure relief valves (SOPRV) and how these maintenance actions may be accounted for in the computation of the PFDavg metric. The method provides a means for quantifying the effects of changes in maintenance practices and shows how these changes impact plant safety.

Performance of a bolted flange joint is characterized mainly due to its ‘strength’ and ‘sealing capability’. A number of analytical and experimental studies have been conducted to study these characteristics only under internal pressure loading. A very limited work is found in literature under combined internal pressure and bending loading. Due to the ignorance of external loads i.e. bending and axial in addition to the internal pressure loading, an optimized performance of the bolted flange joint can not be achieved. The present design codes do not address the effects of combined loading on the structural integrity and sealing ability. To investigate joint strength and sealing capability under combined loading, an extensive comparative experimental and numerical study of a non-gasketed flange joint with two different taper angles on the flange surface and with different load combinations is carried out and overall joint performance and behavior is discussed. Actual joint load capacity is determined under both the design and proof test pressures with maximum additional external loading (axial and bending) that can be applied for safe joint performance.

(2001). Unavailabilty of Redundant Configurations the Effect of Proof-Test Phasing. Safety and Reliability: Vol. 21, No. 3, pp. 22-26.

The Strategic Highway Research Program (SHRP) identified rutting as a major cause of distress for Hot Mix Asphalt (HMA) pavements. The resulting Superior Performing Asphalt Pavements (Superpave(TM)) mix design system specifically addressed the aggregate and asphalt binder properties that contribute to permanent deformation. However, the Superpave(TM) system does not currently include a laboratory proof-test to quickly assess the rutting susceptibility of HMA. In the early 1980's, the Georgia Department of Transportation funded research to develop and refine a laboratory wheel-tracking device. Based on the results of this research, Pavement Technology, Inc. (PTI) developed the Asphalt Pavement Analyzer (APA). Various laboratory studies have been conducted since the development of the APA to assess the suitability of this device as a proof-test for HMA. In 1998, the Tennessee Department of Transportation (TDOT) initiated a study with the University of Tennessee to further evaluate the merits of the APA. In ...

It has been accepted not only that effective proof testing of ceramic materials demands rapid loading and unloading to prevent strength degradation but also that especially rapid unloading results in a truncation strength of σp (the stress just before very rapid unloading). Such an accepted interpretation in proof testings as above has been rechecked from an analytical point of view. The analysis reveals that as the loading and unloading rates increase, weaker samples tend to survive more easily. As a consequence. the truncated strength is not characterized analytically, and the Weibull curve will not have asymptote. The present analytical results come to the conclusion that the established theory in proof testing can not be accepted from the physical point of view.

SO2 monitoring in the flue gas of a coal burning boiler is important for environmental protection. The nonlinearity of practical condition causes deviation from theoretical law. On the basis of the Lambert-Beer Law, a new four-step calibration method is introduced. This method includes cross section interpolation, weighting spectral region combination, acquiring the spectrum with new calibration devices, and least-square fitting. Compared with conventional methods, this new method is low cost, convenient, and accurate. In the proof test, SO2 samples with different concentrations are measured. The average errors are less than 1.5%, while the maximum deviation is less than 4.5%.

It has been accepted not only that effective proof testing of ceramic materials demands rapid loading and unloading to prevent strength degradation but also that especially rapid unloading brings truncated strength of σp (the stress just before very rapid unloading). Such common sense in proof testing as above has been rechecked with analytical considerations. The analysis reveals that as the loading and unloading rate increases, weaker samples tend to survive easily. As a consequence, the truncated strength is not characterized analytically, and Weibull curve will not have asymptotic feature. The present analytical results come to the conclusion that the common sense in proof testing will not be accepted from the physical point of view.

The material and component requirements for ceramic femoral ball heads in total hip replacement systems are described and briefly discussed. Reliability is correlated to the homogeneity of the material in terms of microstructure and Weibull modulus, and to the design of the components. Stress distribution can be analysed by finite element analysis. Based on controlled and specialised processing and the stress analysis data the design can be optimised. Proof testing, as part of final inspection, is an efficient method for eliminating components having strengths at the low end of the strength distribution spectrum.

Outline results are presented from a single experiment in which a 1:100 linear scale model of a spud-can foundation was loaded on a stratified foundation alongside a group of tubular piles. The loading sequence simulated initial landing, static preload proof testing consistent with the usual offshore philosophy for accomodating anticipated in-service cyclic load combinations, through to final removal, of an offshore jack-up rig alongside an existing structure.

Six aerospace-type, filament-wound graphite/epoxy pressure vessels were studied. Four of these cylindrical vessels had each received a single, controlled impact; four had received thermal exposures including moderate heat and/or cryogenic cold. Acoustic emission (AE) was monitored during a proof test sequence (after the impact/thermal exposure), including the final depressurization from proof pressure (i.e., the second unload cycle). A single set of wideband AE sensors was used to simultaneously record parameter-based AE and waveform-based AE on two independent AE instrumentation systems. Some slight to moderately large differences in AE activity for impacted vs. non-impacted vessels were noted for AE from Felicity ramps and holds at pressure. However, dramatic differences were apparent in quantities of AE from the final depressurization cycle: impacted vessels experienced unload AE activity which was a minimum of an order of magnitude greater in quantity than the unload AE activity for non-impacted vessels. This difference provided a distinctive means of identifying those vessels with impact damage. A newly defined "Shelby ratio" was introduced as a means of quantitatively assessing the unload AE; correlations were obtained between vessels' residual strength and the unload "Shelby ratios." Refinements of the parameter-based data analysis approach were made possible by waveform information. Additionally, examination of the waveform data of the unload cycle revealed a significant quantity of "friction" type waveforms having a repeated, lower frequency character; similar "friction" waveforms were able to be artificially generated by rubbing a pencil lead across a composite vessel surface.

Risk-based inspection methods enable estimation of the probability of failure on demand for spring-operated pressure relief valves at the United States Department of Energy's Savannah River Site in Aiken, South Carolina. This paper presents a statistical performance evaluation of soft seat spring operated pressure relief valves. These pressure relief valves are typically smaller and of lower cost than hard seat (metal to metal) pressure relief valves and can provide substantial cost savings in fluid service applications (air, gas, liquid, and steam) providing that probability of failure on demand (the probability that the pressure relief valve fails to perform its intended safety function during a potentially dangerous over pressurization) is at least as good as that for hard seat valves. The research in this paper shows that the proportion of soft seat spring operated pressure relief valves failing is the same or less than that of hard seat valves, and that for failed valves, soft seat valves typically have failure ratios of proof test pressure to set pressure less than that of hard seat valves.

This chapter discusses the repair of metallic aircraft structures with bonded composite patches or reinforcements. Aspects discussed include key materials aspects, including pre-bonding surface preparation and patch application procedures, and an analytical repair design approach, with experimental confirmation. The difficult issue of the certification of bonded repairs to critically damaged primary aircraft structures is discussed. This results from the inability of conventional non-destructive testing to detect weak adhesive bonds. Two approaches to alleviate this difficulty are proposed: structural health monitoring and proof testing. Finally, two applications, one from the United States and the other Australian, are described followed by a conclusion on limitations and lessons learned.

This chapter covers the basic requirements for establishing the appropriate wall thickness for various pipe diameters and the different materials chosen depending on the type of service. The calculations for various types of intersections are covered. The B31 code books review various standards and list those that meet the requirements of the applicable code. They also define what is necessary to meet their requirements. For intersections, code acceptance is a bit more complex than for a piece of straight or bent pipe. Nothing should be added to the pipe that reduces its ability to safely perform its duty of safely transporting its designated fluid. The chapter reviews the ASME standards with regard to various types of intersections, including the various methods and proof tests that have been used to qualify different types of fittings. The steps in developing a generic test are also outlined.

The 29-span highway bridge across the Sava River at Brcko, Bosnia, dates to 1894 and suffered the destruction of four deck trusses during the recent war. Following the deployment of U.S. peace keepers, the swift reopening of this structure was required for their continued supply. The condition of the remaining spans was evaluated to be capable of the expected traffic. A restoration of the damaged spans to a comparable level was quickly designed in the field and was subsequently checked with finite-element analyses. The construction, which involved the extension of piers with mass concrete and the erection of panel bridging, was accomplished in 20 days by an international team of civilian and military engineers. Following a proof test, the bridge has performed reliably with traffic control and structural inspection safeguards. While conventional procedures and equipment were used on parts of the project, several unique problems arose and shortcomings in current military methods were uncovered. The project further serves as an interesting example for practicing engineers faced with the rapid restoration of an important lifeline.

The effect of a proof test on the fatigue strength and lifetime of soda-lime glass specimens is studied. In practice, subcritical crack growth is difficult to avoid during the proof test so that the initial damage should be considered in the design life prediction process. Statistical treatment assumes that the fatigue lifetime depends on the Weibull modulus m, the material and environment dependent exponent n in the crack growth rate model and the eliminated ratio specimens in the proof test. The effect of the proof test becomes increasingly more important as this ratio is increased. For m/(n − 2) = 1, the statistical distribution of the fatigue strength is unchanged after the proof test. If m/(n − 2) becomes smaller than unity, the proof test raises the fatigue strength of the survived specimens, especially at higher survival probability, and reduces the scatter of the fatigue strength data. Hence, the reliability of the survival components is improved. The opposite occurs when m/(n − 2) becomes greater then unity.

Coil springs made of silicon nitride (Si3N4), which has higher strength and heat resistance than other ceramics, have recently developed. By examining the range of strengths and the heat resistance of the coil springs, it is shown that the coil springs can be used at temperatures up to 1000°C. Using Weibull failure theory, we derive an equation to calculate effective volumes of coil springs and examine the influence of effective volume on the strength of coil springs. The results show that the mean strength of coil springs decreases with increasing effective volume. Therefore the strength of coil springs can be estimated from an equation of the effective volume, and this equation can be used in design of coil springs. Furthermore, by conducting proof tests, coil springs that have relatively large defects can be eliminated and so only highly reliable coil springs can be placed in service.

A new press working with increasing thickness for automobile parts was examined using elastoplastic FEM analysis. The main results were obtained as follows : (1) The mechanism of increasing thickness was determined by the FEM analysis parameter of strain. That is, the effect of increasing thickness of plate was achieved by increasing the strain in the circumferential direction. (2) The suitable press working of a piston-pulley was examined by means of FEM analysis. It was suggested the forming with increasing thickness. (3) A close agreement between the results of a proof test and analytical results was obtained. So it was confirmed that the new press working with increasing thickness of plate was useful in practice.

This paper proposed an approach to model Safety Instrumented Systems (SIS). The model is based on Multiphase Markov Chains and integrates several parameters like Common Cause Failure, Diagnostic Coverage, Proof testing, etc. The basic concepts of the Markov chains applied to availability analysis are introduced and a model to compute the unavailability for a case study is presented. We show how the variation of some characteristic parameters induces significant changes on the safety level of the SIS. The proposed method ensures the relevance of the results.

Horticultural therapy is the emerging service industries in China. This article summarizes the concept, the applicable objects, the target, the characteristics and the efficacy of the horticultural therapy. And explains the basic composition of horticultural therapy activities as well as the famous Japanese horticultural therapy rehabilitation facility, comfort garden Azomino for example. It also proposes the way of promotion of horticultural therapy of Shenzhen area in China, the effect of proof test multimode promotion cooperate with pension institutions, for the promotion of horticultural therapy of more cities and regions in China to lay the foundation.

Fracture mechanics has evolved into an engineering tool able to solve problems related to the safety of structures containing defects. In practice, however, a wide choice of parallel methods as well as unsolved discrepancies in the theory requires engineering judgement and pragmatism. In this paper a practical case study is presented, concerning a maintenance strategy assessment performed on a welded pressure vessel. The pressure vessel is analysed in terms of leak-before-break arguments, proof test logic, fatigue initiation life, defect initiation and unstable growth critical sizes, fatigue crack propagation that leads to fracture or leakage, as well as probabilistic methods based on defect size distributions and NDE detection probabilities. The paper deals with some background to the theories employed, the different steps of the assessment methodology, as well as with the interpretation of the result to design a practical and safe maintenance strategy.

Systematic investigation of the properties of solids requires an understanding of their microstructure, extending from the nanoscale (atomic arrangement) to the millimetre scale (grain size, crack lengths). In this sense, the prefix "micro" is really the geometric mean of "nano" and "milli" – it refers to structure that has, until recently, been ignored by physicists more concerned with electronic structure and by chemists more concerned with molecular structure. Its study has been the domain of metallurgists and engineers and, by revealing the mechanisms underlying physical processes, it complements the proof testing that guarantees the safety of engineering structures. Nowadays it plays a considerable role in forensic science, conservation of museum pieces, bioengineering and in practically every activity where the state of a material crucially affects human safety or well-being.

Pressure vessels are periodically subjected to a proof test to assure structural integrity. During that period, it may be possible to control the fatigue crack growth by simultaneous heating globally or locally around a crack tip. From this viewpoint, retardation behavior of a fatigue crack due to a single peak overload at a high temperature (∼300°C) was examined in an A 533 B-1 steel. Parameters investigated were overload ratio, applied temperature, hold time at higher temperature, and unloading temperature of overload. The higher the applied temperature, the greater the effect of retardation especially when unloading of the overload is done at lower temperatures. Also, the hold time at maximum load promotes oxide-film-induced crack closure. To evaluate those effects, a simple model is proposed based on the Dugdale model.

In order to investigate the effectiveness of high-temperature proof testing in silicon nitride, static fatigue tests at l000°C were conducted using the specimens with and without proof testing at l000°C. The experiments were conducted in air under four-point bending. The times to failure of survivors of proof testing were measured and compared with that of as-received specimens, and the relation-ship between the proof-testing effect and the proof-testing conditions was investigated. It was clarified that high-temperature proof testing was influenced by oxidation of specimen surface and loading rate of proof stress.

Since 1974 Biolox ceramic femoral ball heads have been used successfully for artificial modular hip joints. The revision rate due to ball head fracture is lower than 0.02%. This is an extremely low value. In this article it is shown how the safety of a ceramic ball head can be improved using the procedures of HIPing, engraving by laser technique, and 100% proof testing. By applying these means the materials properties density, grain size, grain size distribution, and the strength of the ball head, i.e. the fracture load can be improved significantly.

This paper addresses dangerous failures of stainless steel (SS) trim spring operated pressure relief valves (SOPRV) due to a particular failure mode (SS-to-SS adhesion) which is not currently being included in SOPRV failure rates. As a result, current methods for estimating or predicting failure rates for SS trim SOPRV significantly underestimate these failure rates and, consequently, overestimate the safety provided by the SOPRV as measured by its average probability of failure on demand (PFDavg) or its corresponding safety integrity level (SIL). The paper also illustrates the critical importance of root cause analysis (RCA) of dangerous SOPRV failures in understanding the impacts of various failure modes. Over 1300 proof test results for both new and used SS trim SOPRV from the Savannah River Site (SRS) were identified. RCA was used on the failed valves to classify those failed due to SS-to-SS adhesions. Statistical analysis of the data convincingly demonstrates adhesions, previously assumed to be only an in-storage failure phenomenon, are also an in-service failure mode which needs to be included in SOPRV failure rates. The paper discusses the factors which potentially influence the adhesion failure mode and suggests a possible approach to including this mode in failure rate predictions. An example illustrates how current failure rate models overestimate SS trim SOPRV safety by one or two orders of magnitude.

This paper investigates the use of proof (or acceptance) test data during the reliability based design optimization of structural components. It is assumed that every component will be proof tested and that the component will only enter into service if it passes the proof test. The goal is to reduce the component weight, while maintaining high reliability, by exploiting the proof test results during the design process. The proposed procedure results in the simultaneous design of the structural component and the proof test itself and provides the designer with direct control over the probability of failing the proof test. The procedure is illustrated using two analytical example problems and the results indicate that significant weight savings are possible when exploiting the proof test results during the design process.

A 1.5 x 2.8 m, 44.5 m deep barrette was constructed in weathered sedimentary rock of the Jurong formation in Singapore with an O-cell assembly of two O-cells installed at 33.5 m depth, 11 m above the barrette toe, chosen presuming that resistance above and below the cell level would balance. When the O-cell test was performed, a proof test at the end of the construction work, the shaft resistance for the section above the O-cell level was surprisingly low; the shaft failed at a load of only about 3 MN. In a re-test, at the maximum O-cell load of 12.5 MN, the upward movement exceeded 100 mm. The barrette was then tested in a conventional head-down test, which first (second test stage) was with the O-cell vented to validate the results of the O-cell test. In a third stage, the opening between the O-cell plates was grouted in order to transfer load across the O-cell level to mobilize the shaft resistance along the lower section of the barrette and the toe resistance. The results of Stage 1 O-cell upward test and Stage 2 head-down test on the pile with free-draining O-cell agreed well, as did the Stage 1 equivalent head-down test and Stage 3 head-down test. Stage 3 test confirmed a 12 MN working load, downgraded from the original 33 MN value. The test results are discussed and referenced to a numerical (FEM) analysis.

Publisher Summary Pressure tests are carried out to induce a pre-determined stress level in a sample, by pressurizing the equipment and observing the results. The test is carried out by increasing the internal pressure, and creating a pressure differential with ambient pressure. This allows liquid to flow out of possible openings; that is the leak. This is inspected by visual methods. The media used for leak testing can be any liquid that is non-hazardous to personnel or the environment. The test can be made more effective and sensitive by use of lighter chemicals, gases or by the addition of fluorescent dyes to the water. Proof testing is a relatively high-pressure test compared to the leak test. The proof test is generally designed to subject the material to stresses above those that the equipment is expected to carry in service. The methods of testing vary according to the specific design and requirements of service. There are several types of flaws that can be detected by hydrostatic testing.

Cyclic fatigue behavior of silicon nitride was investigated at 800°C in air, and proof tests as a method of improving reliability of fatigue life were carried out at room temperature. Fatigue life distributions for σmax=833 MPa were compared before and after proof testing on a Weibull plot. The truncated fatigue life distribution after proof testing did not coincide with the theoretical curve Fp (Np), and some fatigue life data after proof testing were shorter than the theoretical minimum life Npmin. Fp (Np) and Npmin were predicted when no slow crack growth occurred during proof testing. A statistical method was developed to predict actual truncated fatigue life distribution Fp'(Nf) and minimum life Nfmin after proof testing. The predicted curve was consistent with the experimental life data, and Nfmint0.27Npmin. From the minimum life Nfmin predicted by our method, the influence of proof testing on fatigue life was estimated in terms of the degradation of truncation strength due to slow crack growth during proof testing. It was found that the truncation strength was t0.94σp, where σp is proof stress.

Mechanics analysis model of laminated solid armature is established by finite element in this article. The orthogonal method is applied in simulation experiment of laminated armature. The contact pressure between armature and rail is studied based on parameters of armature's thickness, material, layers, and length of the tail. Using range analysis method, contained by orthogonal analysis, the order of the factors which affecting the interface stress is the thickness of the outermost armature, the length of the tail, and armature materials. Through the analysis method of variance, the thickness of the laminated armature does the highest performance of the three factors. At last the analysis result is correct by the proof test.