Simple Test Setup Research Articles

D-box fixture for testing stiffened panels in compression and pressure

A combined loads test machine used to test aircraft primary structures such as fuselage and wing sections is described. The design features of a D-box test fixture that provides a simple test setup with the flexibility to accommodate curved stiffened panels of different radii are presented. Linear finite element analysis results from studies performed to evaluate and to address problems associated with load introduction into a curved panel when tested in the D-box test fixture with compression and internal pressure loading are also presented and discussed. From the analysis results it is determined that by providing cross bars with adjustable lengths in the D-box test fixture, appropriate boundary conditions and the proper load distributions can be simulated for undamaged and damaged curved panels with different frame spacing subjected to internal pressure and axial compression. Nonlinear shell analysis results for both the internal pressure and combined internal pressure and axial compression cases suggest that the deflection and stress states in the panel for these load cases are much larger than those obtained from linear analysis.

傾斜機能溶射皮膜の温度落差繰り返し熱衝撃特性

In the study of the functionally gradient material (FGM) systems as for the high temperature structural materials, designing of these and evaluation of their thermal shock properties under the temperature gradient condition would be the most essential problems to be investigated. In this study, ZrO2/NiCrAlY functionally gradient plasma sprayed coatings were produced on the stainless steel substrates. Simple heating-cooling thermal shock testing apparatus was made, and repeated thermal shock resistance properties of the coating specimens under the temperature gradient conditions were investigated using this apparatus. Conventional thermal shock test regulated by JIS was also conducted. Moderate coating configuration for minimizing the thermal stress were estimated by the simple analytical model.The results obtained are summarized as follows, (1) Feasibility of the functionally gradient coating were verified by the temperature gradient thermal shock testing conducted using the simple apparatus made.(2) The effect of coating configuration on the repeated thermal shock resistance properties could be evaluated by the temperature gradient test condition.(3) From the results of simple numerical analysis, the moderate coating configuration profile of the functionally gradient coatings was given as the compositional distribution parameter P of less than 1.

Simple technique for obtaining approximate thermal expansion coefficients of low expansion materials: applications to Zerodur

A simple interferometric test setup for measuring thermal expansion coefficients as low as 1 × 10−8/°C is described. The sample to be tested is polished optically flat, interference fringes are formed between the front surface of the sample and a reference surface, and their movement, as boiling water is applied to the back side of the test piece, is observed. When this process was applied to Zerodur, approximate agreement with expected values was achieved. A small permanent change in the Zerodur optical figure occurred as a result of this test procedure, suggesting that Zerodur should not be exposed to strong thermal shock during use.

The two-dimensional in vitro passive stress-strain elasticity relationships for the steer thoracic aorta blood vessel tissue

A simple and inexpensive biaxial test apparatus was developed and is described herein for the two dimensional testing of 5 cm square specimens of the aorta blood vessel tissue. Based on the results of the in vitro biaxial specimen testing the derivation of the passive two dimensional constitutive equations relating longitudinal and tangential stress, strain, and tissue elasticity are described. This is accomplished at each of three longitudinal locations along the thoracic aorta tree and a detailed comparison of the material properties at each location is made.

A new engineering-geological rock durability classification

The construction of the 5.3-m diameter, 82-km long Orange—Fish Tunnel in the Republic of South Africa, in sensibly horizontal beds of mudrocks, siltstones and sandstones of the Karoo Supergroup (Upper Carboniferous to Triassic age), revealed the paramount importance of rock durability. The presence of non-durable rock types was found to be one of the causes of the rock distress problems encountered in some tunnel sections during construction. Geomechanical tests conducted on representative samples of potentially difficult rock types from the Orange—Fish Tunnel, indicated important limitations of international rock material classifications, such as the Deere—Miller Modulus—Strength and the Deere—Gamble Durability—Plasticity systems. The inadequacy of these classifications in the case of the Karoo sedimentary rocks, underlined the need for a new rock durability classification which could be used for the timely indication of the presence of non-durable rock material sections at tunnel level. An account is given of the lithology, mineralogy and the postulated weathering mechanics of the Karoo rocks encountered, as well as the application of these parameters to the numerical methods used for the quantitative assessment of rock durability. It is considered that a reliable appraisal of this time-dependent parameter can be provided by the measurement of the strength and free swelling properties of the intact rock material. A new rock durability classification, styled the Geodurability Classification, is discussed. This empirical system appears to be practical and simple as it depends on the minimum number of index rock properties, which can be measured fairly rapidly in a field laboratory by means of simple test apparatus and semi-skilled labour. It is based on different ranges of ratios of the uniaxial compressive strength, σ c, and the “Duncan” free swelling coefficient, ε D, as index parameters. The intact rock material is classified according to a rating system which varies from “excellent” (Class A) to “very poor” (Class F). The extensive use of the Geodurability Classification indicated such a system to be particularly relevant to compacted and weakly cemented rocks, where the tendency of the rock material to deteriorate with time (and not the presence of rock discontinuities such as joints and bedding planes) dominates the time-dependent behaviour of tunnel rock masses.

Predicting the service life of polysulfone in steam or hot water

AbstractA quantitative definition of stress‐environmental, interactions on polymers must be made in order to designstructural parts. This definition for design urposes is best obtained by measuring creep of the plastic under constant stress and in the environment in which it is to perform. In order to measure creep in steam or hot water, a relatively simple test apparatus was devised so that clamped circular test specimens acting as a diaphragm were stressed by controlled steam pressure. Creep was measured by deflection of the diaphragm. A case history was developed with polysulfone: the allowable stress limits at various temperatures were determined; and a method developed for predicting the long time service life of the material from short time data using the Goldfein equation of state. Creep measurements over a year in steam were in excellent agreement with predicted values.

An efficient alignment procedure for large photomultiplier arrays

A systematic and general approach to the problem of photomultiplier alignment is presented. The method is based on the use of a standard dynode resistor chain for each tube together with an additional set of selectable resistors chosen to provide the prescribed gain. A simple theory is developed to allow gain adjustments over a range of 1000:1 while at the same time ensuring against current saturation effects. The theory was applied to the selection of nine photomultipliers for a large scintillation counter and a simple test apparatus devised for the purpose is described. The method is sufficiently general for application to other experiments where a large number of tubes must be aligned in as few steps as possible. The procedure also provides information on the relative noise performance of each tube tested.

Screen Test for Large Mirrors

A shop method for testing large mirrors using a square-array sampling screen has been developed. The main features of this method are simple test setup independent of random air turbulence, high surface sampling rate, reliability and repeatability of results, detection of surface departures +/-0.1lambda (at 5000 A) or greater from the ideal surface, and self-calibration. Only large-area departures can be accurately detected by this method.

A Simple Set-up for Measurement of the Collector-to-base Time Constant

The high frequency design of a transistor circuit requires knowledge of some additional transistor parameters. The collector-to-base time constant is an important parameter because the maximum frequency of oscillation in the very high frequency range is limited by fT and rb, Cc. The present paper describes a simple test set-up for the measurement of rb, Cc. The input frequency and voltage are adjusted to 31·9 MHz and 0·5 volt rms respectively to simplify the measurements. The results were in good agreement with the values claimed by manufacturers.

A new technique for mounting and testing frame-supported homograft aortic valves.

The mounting of homograft aortic valves on rigid frames often produces cusp distortion leading to mechanical dysfunction. This dysfunction can be demonstrated by a simple testing apparatus. A technique of valve mounting has been developed which consistently results in a competent valve with exact and correct cusp apposition. It is clear that the effect of different techniques of sterilization and preservation on valve function cannot be adequately assessed unless valves are mechanically correct at the time of insertion.

Peel adhesion of PVC to steel

AbstractThe adhesion of PVC to various steel surfaces has been studied using a simple peel test apparatus. The effects of surface cleanliness, phosphate coatings, and oxide films on adhesion have been studied, and studies of oxide film thickness indicate that forces other than those usually considered in models of adhesion may be operative.

A bench‐scale method for evaluating the processing characteristics of oilseeds for filtration‐extraction

SummaryA simple laboratory testing apparatus and its use have been described. With relatively few pounds of material it is possible to evaluate many preparation and filtration variables and to predict with a fair degree of accuracy the behavior of a continuous horizontal vacuum filter. It is felt that such a unit will be invaluable for use in commercial plants, especially during the start‐up operations of a new plant. The bench‐scale unit should also find application in connection with other processes employing the unit operations of extraction and filtration.

Studies of tracking behavior. I. Rate and time characteristics of simple corrective movements.

Using a simple test apparatus, Ss were required to make arm-hand corrective movements of five to 80 millimeters in extent. The results show that: 1. The maximum rate and average rate of a movement increase systematically with increasing extent of movement. The relation is approximately linear in most cases… Reaction times are relatively independent of the distance to be moved. 2. In the situations studied, rates are highest for movements from left to right and are successively lower for forward, left, and backward movements. 3… For movements of comparable distance in each case, rates at the pointer are slightly lower, and rates at the hand are higher at the 3:1 than at the 1:1 ratio [of control sensitivity]. In general, the operator tends to compensate for the change in sensitivity in such a way as to produce nearly the same perceived result with respect to both rate and accuracy. 4. The addition of an appreciable amount of inertia to the control knob causes the rate to be decreased for given distances of movement and the precision to be slightly improved. With additional friction… the responses are speeded up and precision is definitely lower than when minimum friction is present… . (PsycINFO Database Record (c) 2012 APA, all rights reserved)