Stiffened plate

In the Uhde [986], [987] and Steinmiiller [989] concept the tubesheet is anchored to and supported by the tubes to withstand the differential pressure, which imposes some restriction on the tube length. Babcock-Borsig s [988], [990], [991] tubesheet is reinforced by stiffening plates on the back side (Figure 100). Both solutions have full-penetration tube-to-tubesheet welds for the tubes to prevent crevice corrosion. Struthers [992] reduces stress by making the tubesheet-to-shell connection flexible. 

A cross-ribbed design only provides stiffening in the two rib directions. There is a low bending stiffness along a direction at 45° to the ribs, and a low torsional stiffness. An isotropic stiffened plate needs ribs in at least... 

For local loads where a partial ring stiffener is to be used to reduce local stresses, the beam on elastic foundation method provides an ideal method for sizing the partial rings or stiffener plates. The stresses in the shell must then be analyzed by another local load procedure. Shell stresses can be checked by the beam-on-elastic-foundation method for continuous radial loads about the entire circumference of a vessel shell or ring. 

Many opportunities exist currently in the remedial markets, in the fabrication of aluminium and steel assemblies and, in particular, for stiffened plate structures. Great advantages can be derived from combining material combinations and, indeed, from combining adhesive bonding with some form of mechanical attachment to create composite harmony. 

A glue line of minimum 0.5 mm is used and the thixotropic adhesive is required to fill gaps up to 3 mm in the vertical or horizontal plane. Attachment of the heavy steel stiffening plate requires a few bolts to carry the load whilst the adhesive is setting. The bolts are set back from the edge of the plate in a low stress area so that the hole and the bolt do not interfere with the function of the stiffener (Fig. 41). 

Consider a thin plate of homogeneous, isotropic and linearly elastic material with modulus of elasticity E and Poisson ratio v, having constant thickness hp and occupying the two dimensional multiply connected region of the x,y plane bounded by the piecewise smooth fC-fl curves ro,ri,...,rx-i,rx, as shown in Fig. 1. The plate is stiffened by a set of /= 1,2,..., 7 arbitrarily placed parallel beams of arbitrary doubly symmetric cross section of homogeneous, isotropic and linearly elastic material with modulus of elasticity and Poisson ratio which may have either internal or boundary point supports. For the sake of convenience the x axis is taken parallel to the beams. The stiffened plate is subjected to the lateral load g = g(x, r), x x,y, t>0. For the analysis of the aforementioned problem a global coordinate system Oxy for the analysis of the plate and local coordinate ones O x y corresponding to the centroid axes of each beam are employed as shown in Fig. 1. 

Figure 4 Plan view, section a-a and loading of the stiffened plate of Example I.

A rectangular plate with dimensions Ipx x Ipy = 18.0 x 9.0 m stiffened by a rectangular beam of 1.0 m width eccentrically placed with respect to the center line of the plate (Fig. 4) has been studied (damping ratio = 1 = 0). In Table 1 the torsion 7 and warping 7 constants of the beam cross section and the values of the primary warping function (4>s)ff (/ = Ij 2) at the nodes of the two interface lines for various beam heights are presented. In Table 2 the computed first five eigenfrequencies, in Fig. 5 the fundamental modeshape and in Fig. 6 the deflection time history at point C (Fig. 4) of the stiffened plate for the cases of a partial in both directions and a full shear connection... 

Fig. 8 the deflection time history at point C (Fig. 7) of the stiffened plate subjected to the accelerogram of Athens Earthquake at September 7, 1999 for the cases of a partial in both directions and a full shear connection are presented as compared with those obtained from FEM solutions. 

The influence of the interface slip to the behavior of the stiffened plate and the accuracy of the obtained results compared with those obtained from FEM solutions are verified. 

There is a side collision protection consisting of reinforced plates in the hull and deck plating adjacent to the board and longitudinal stiffening plates of the board to protect against ship collision ... 

It has since been noted that the presence of the stiffening plates actually induces the hydrophones to operate in a thicknen (33) mode as opposed to a hydrostatic mode (3]. This may be attributed to the fad that the stiffener layer laterally clamps the active fdroelecsric polymer layer such that there is no exdlation of the p.l) and (33) modes. The first stiffening layers were thick plates of epoxy-loaded gra diiie and aluminum. Later it was found that electroplating thick copper-plated PC board laminates onto the ferroelectric polymer was effective as a combination stiffener layer and electrode. 

Roussis PC, Constantmou MC (2006) Uplift-restraining fiiction pendulum seismic isolatitm system. Earthquake Eng Struct Dyn 35(5) 577-593 Zheng Y, Das PK (2000) Improved resptmse surface method and its applicatimi to stiffened plate reliability analysis. Eng Struct 22 544-551... 

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