Geometric imperfections

Amongst other advantages, these materials offer the opportunity to utilize in a positive way geometric imperfections. In other words, similar... 

Role of Geometric Imperfections in the Collapse of a Cooling Tower Kemp, K. O. Croll, J. G. A. 

In Fig. 10 a spectrum of resonances measured for CH4 in a cylindrical cell with 1 = 102 mm and ro = 51 mm is shown for illustration. Not only the fundamental modes, but also combinations of these modes are oteerved. Identification of the resonances can be difficult, if geometric imperfections and dissipation processes lead to larger frequency shifts. 

Crazing in glassy homo-polymers is overwhelmingly a surface phenomenon. In the few instanees when crazing was found to occur in the interior the source of this has always been particulate inclusions surrounded by misfit stresses and signifi-eantly different elastic properties (Kambour 1973). The surface sensitivity of erazing derives from the presence of geometrical imperfections on surfaces. When... 

Waszczyszyn, Z. Bartczak, M. 2002. Neural prediction of buckling loads of cylindrical shells with geometrical imperfections. International Journal of Non-Linear Mechanics 31 763-775. 

In the absence of other provisions, the influence of structural imperfections may be assessed by representing them as an effective geometrical imperfection using a procedure such as that given in (4) to (8)... 

The comparison between the measured N values and the theoretical ones gave an indication of the geometrical imperfections of the trusses plus the inaccuracy of centring on the machine (see Figure 4). Their order of magnitude was estimated to be +2 mm. 

Cylinders under axial compression are more sensitive to geometric imperfections in the elastic range than in the... 

Application of a layer of epoxy gluing adhesive on the freshly applied primer following the instructions provided in the related technical sheet, with a view to eliminating any possible geometric imperfections on the support... 

As far as the author is aware, the effects of real geometric imperfections in column buckling analyses of pultruded GFRP profiles have not been investigated thoroughly. As mentioned above, only maximum values of... 

Kwok, K., Frandsen, H.L., Sogaard, M., and Hendriksen, P.V. (2014) Mechanical reliability of geometrically imperfect tubular oxygen transport membranes. 

It has been found that the liquid surface tension values measured from sessile drops are less accurate than those obtained from pendent drops. This is a consequence of the assumption that the drop shape is axisymmetric. While the shape of sessile drops is very sensitive to even a very small surface imperfection, such as roughness and heterogeneity, axisymmetry is enforced in the case of a pendent drop through the circularity of the capillary orifice supporting the drop, thus resulting in more reliable surface tension results. The contact angle measurement, on the other hand, is less sensitive to geometrical imperfections than the surface tension measurement. 

The actual thickness of all the columns varied along their height and was surprisingly reduced in all the columns on the second floor. It should be noted that it was very difficult to obtain reliable information about the actual external and internal geometrical imperfections of the cast-iron columns. 

Various uncertainties may exist about the real material properties and geometric imperfections of the cast-iron columns of the industrial heritage building. However, there is a clear evidence that the heritage structure of the spinning factory withstood for more than one hundred years considerably greater imposed loads than presently required for residential purposes. 

Moreover, it is verified for this example also that the elastic critical load derived from linearized buckling analysis is reduced significantly due to geometric imperfections and material yielding. 

Schneider W, Biede A (2005) Consistent equivalent geometric imperfections for the numerical buckling strength verification of cylindrical shells under uniform external pressure. Thin-Walled Struct 43(2) 175-188 Schneider W, Timmel I, Hdhn K (2005) The conception of quasi-collapse-affine imperfections a new approach to unfavourable imperfections of thin-walled shell stmc-tures. Thin-Walled Struct 43(8) 1202-1224 Stricklin JA, Haisler WE, von Riesemann WA (1973) Evaluation of solution procedures for material and/or geometrically nonlinear structural analysis. AIAAJll(3) 292-299... 

The applicability of the elastic critical load, as in Eq. 4, to pile buckling failure is an important factor. Experiments show that the actual failure load of a slender column is much lower than that predicted by Eq. 4. Rankine (1866) recognized that the actual failure involves an interaction between elastic and plastic modes of failure. Lateral loads and inevitable geometrical imperfection lead to creatifMi of bending moments in addition to axial loads. Bending moments have to be accompanied by stress resultants that diminish the cross-sectimial area available for carrying the axial load thus the actual failure load is likely to be less than the elastic critical load,... 

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