- ItemOpen AccessCompound strip method for the analysis of continuous elastic plates(Colorado State University. Libraries, 1983-10) Puckett, Jay A., author; Gutkowski, Richard M., author; Colorado State University. Civil Engineering Department, publisherA finite strip method (FSM) is developed for the analysis of Iinear elastic flat plate systems which are continuous over deflecting supports. The approach presented incorporates the effect of the support elements in a direct stiffness methodology. The stiffness contribution of the support elements have been derived and are given In the form of strip matrices which are directly added to the plate strip stiffness matrix at the element level. This summation of plate and support stiffness contributions constitutes a substructure which is termed a compound strip. The validity of the compound strip method is demonstrated in several illustratlve problems which include single and muitlpanel plates continuous over flexible and rigid beams and columns. The FSM and finite element method (FEM) compare favorably for displacement and moment. The rate of convergence of the compound strip method was studied and results are given for a continuous multipanel system. The FSM is shown to be computationally more efficient than the FEM when maximum values for moment or deflection are required. The FEM exhibits favorable convergence characteristics in locations where the magnitudes of displacement and moment are relatively small.
- ItemOpen AccessNondestructive evaluation of wood properties by stress wave spectral analysis(Colorado State University. Libraries, 1982-11) Shaler, Stephen M., author; Bodig, Jozsef, author; Histand, Michael B., author; Colorado State University. Civil Engineering Department, publisherThe influence of selected properties on the propagation of stress waves in wood was investigated. Waveform analysis of the stress waves was performed using spectral analysis techhniques developed for stationary random processes. Information analyzed from the stress waves included wave velocity, energy spectra, and the frequency response function. Three wood properties investigated as to their influence on stress waves propagation were grain angle, moisture content, and weight loss caused by decay. Significant relationships between grain angle and the wave properties of velocity, amplitude gain, and total gain were obtained. Significant damping of the stress waves was observed at large grain angles and moisture content values above the fiber saturation point. No significant equations were found for consistent prediction of moisture content. The results of the decay study showed that as weight loss increased, the ratio of energy of the stress wave to that input to the specimen decreased for the perpendicular to grain case. Two approaches toward prediction of wood strength were investigated. The first method employed prediction of wood properties from the stress wave spectral characteristics. Known relationships between these wood properties and strength were then utilized. The second approach involved direct correlation of the stress wave spectral properties with strength. Significant correlatlons with strength were obtained using both approaches. Application of basic results are discussed as to their applicability toward development of an [sic] nondestructive evaluatlon (NOE) procedure for wood poles used in transmission line structures.
- ItemOpen AccessLayered beam vibrations including slip(Colorado State University. Libraries, 1972-06) Henghold, William Murray, author; Department of Civil Engineering, Colorado State University, publisherThis study presents a theory for vibrations of layered beams with the effects of interlayer slip included. The theory is developed using Bernoulli-Euler assumptions with additional developments to account for the interlayer movement. The development is general, in the small deflection sense, for beams with mechanical connections. The development leads to governing equations for beams having both dual and single axes of symmetry and an arbitrary number of layers. Solutions to the governing equations are presented in closed form for various sets of boundary conditions. These solutions show the effect of interlayer connection on the natural frequency, and it is shown that the solutions reduce to well known values for the extremes of interlayer connection. The effect of damping on the solutions is presented, and the equations for the damped system are solved for small damping. The results of some simple tests which were performed are presented, and these results are shown to agree favorably with the proposed theory.
- ItemOpen AccessModeling of velocity distributions inside and above tall crops(Colorado State University. Libraries, 1965-06) Plate, E. J., author; Quraishi, A. A., author; American Meteorological Society, publisherVelocity distributions inside and above a model crop were investigated. The model crop consisted of flexible plastic strips fastened to the floor of a low speed wind tunnel. The experimental results indicated that at some distance xo downstream from the edge of the roughness cover the velocity profiles were similar inside and also above the cover. The length xo is discussed. The experimental results for the velocity distribution inside the plant cover were compared with field data obtained from different sources. A presentation of the velocity profiles inside the canopy in nondimensional form collapsed all field and laboratory data for a given crop type on one curve. The laboratory flow above the crop cover was analyzed using a power law form and using the logarithmic velocity distribution law. On the basis of the experimental results it is recommended that a two-tower arrangement of wind velocity measuring devices be used both for the evaluation of the surface shear stress and for checking the establishment of similarity profiles in the field.
- ItemOpen AccessDiscussion of "River depletion resulting from pumping a well near a river"(Colorado State University. Libraries, 1955) Glover, Robert E., author; Balmer, Glenn G., author; American Geophysical Union, publisher