Eccentric load test

At this point, a brief description of the test machine and necessary modifications seems in order. The machine is a Tatnall-Krause (5000-lb capacity) direct-stress fatigue machine with an eccentrically loaded lever arm. A hydraulic load-maintaining system is incorporated in the machine and is installed above the supporting columns. This system is electronically controlled. By using this system, a constant load pattern is maintained on the sample even though its length may increase during the test. 

According to test data determined by Ba.ztJiyra (1979), Kudzys and Kliiikas (2008), the statistics RNm = 0.99, (tOrn = 0.06 — 0.08 and 0RMm = 1.02, (tOrm = 0.06 — 0.08 for the columns of braced and bracing piers, respectively. The standard deviation oOr = 0.06 — 0.08 is also recommended by Szerszen et al. (2005) as statistical parameter for reliability analysis of eccentrically loaded columns. 

In the absence of more rigorous methods or direct applicable test results, the following method of analysis may be used for simple concentrically and eccentrically loaded double lap joints between structural members, of which at least one must be of glass FRP (provided that the preceding design requirements are met). 

A complete balance test consists of a systematic set of weighings designed to evaluate all aspects of balance pterformance. including repeatability, eccentric loading errors, linearity, and span calibration. For a balance to be declared in proper working condition, all test results must fall within the tolerance limits specified by the manufacturer. These tolerances normally apply only to new or newly serviced equipment. In other cases a so-called in-service tolerance—equal to twice the original tolerance—is customarily allowed. 

Besides the examples that have been given, more phenomena can be studied with the model. For instance, the influence of imperfections in test performance, like eccentric loading in case of hinges or the existence of an initial rotation in case of... 

For a new process plant, calculations can be carried out using the heat release and plume flow rate equations outlined in Table 13.16 from a paper by Bender. For the theory to he valid, the hood must he more than two source diameters (or widths for line sources) above the source, and the temperature difference must be less than 110 °C. Experimental results have also been obtained for the case of hood plume eccentricity. These results account for cross drafts which occur within most industrial buildings. The physical and chemical characteristics of the fume and the fume loadings are obtained from published or available data of similar installations or established through laboratory or pilot-plant scale tests. - If exhaust volume requirements must he established accurately, small scale modeling can he used to augment and calibrate the analytical approach. 

To enable the determination of almost pure strength values for the adhesive layer, the parameters eccentric application of load and adherend extension/ deformation must be eliminated. This is the case in the test piece geometry depicted in Figure 10.4 according to the standard ISO 11003-2 Shear testing method for thick adherends . 

There is no exact theoretical formula that gives the strength of a column of any length under an axial load. Different formulas involving the use of empirical coefficients have been deduced, however, and they give results that are consistent with the results of tests. These formulas include the popular Euler s formula, different eccentric formulas, crossbend formulas, wood and timber column formulas, and general principle formulas. 

As expected LI has the highest compressive strength, followed by S2 and SI. However, if the test is to be used as an effective means of comparison of the compressive strength between the different parts of the panel, the values must be taken with care because of the possible buckling behaviour (load eccentricity due to the particular geometry of the specimen) which could occur before fracture. 

Apparently, dispersed fibres do not appreciably modify the behaviour of cement-based elements subjected to creep. There have been few experimental studies of this problem and the results obtained are inconclusive. As mentioned above for shrinkage, modification of the internal structure of composite materials causes quite complex results and comparisons are difficult. In several reports, similar behaviour of plain and fibre-reinforced elements was observed under creep conditions, both qualitatively and quantitatively. However, extensive studies executed by Swamy et al. (1977) proved that fibre-reinforcement decreased creep considerably. Similar conclusions were formulated by Brandt and Hebda (1989) who tested elements under eccentric compression in long periods of time. The creep was small for reinforced specimens. The most important factor relating to the final creep values was the level of load with respect to the material s strength and that factor was also influenced by the volume of fibre reinforcement. That was the reason why the creep recovery measurements carried out by different authors did not furnish consistent results. 

At each steady load - speed combination, test rig temperatures were stabilised and the data obtained for the determination of attitude angle and eccentricity. Data reported in this paper were all obtained at a single value of steady eccentricity ratio and attitude angle. Time histories of the bearing housing horizontal and vertical displacements relative to the journal, external dynamic forces and... 

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