buckling of thin plates
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Buckling of thin PlatesTRANSCRIPT
Student:Lamyaa MohsinBuckling of thin platesAdvanced Theory of ElasticityFILS, M I, STRUCTURAL ENGINEERING1In the calculation of critical values of forces applied in the middle place of a plate, the same methods as in the case of compressed bars can be used.
The equation for the buckled plate is
How presentation will benefit audience: Adult learners are more interested in a subject if they know how or why it is important to them.Presenters level of expertise in the subject: Briefly state your credentials in this area, or explain why participants should listen to you.2Buckling of Simply Supported Rectangular Plates Uniformly Compressed in One Direction.
Assume that a rectangular plate (Fig. 1) is compressed in its middle plane by forces uniformly distributed along sides x = 0 and x = a.
The Navier solution for the deflection way may be used:The strain energy of bending in this case is
Lesson descriptions should be brief.
3The work done by the compressive forces during buckling of the plate, will be
Thus Eq. (2), for determining the critical value of compressive forces, becomes
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The first factor in this expression represents the Euler load for a strip of unit width and length a. For a plate of a given width the critical value of the load is smallest if the plate is square. In this case
The critical load, with m = 1, in expression (e), can be finally represented in the following form:
For other proportions of the plate the expression (g) can be represented in the form
Let us assume now that the plate buckles into two half-waves and that the deflection surface is represented by the expression
For calculating the critical load we can again use Eq. (g) by substituting in it a/2 instead of a. Then
in which k is a numerical factor, the magnitude of which depends on the ratio a/b. this factor is presented in Fig. (2) by the curve marked m = 1. The transition from m to m + 1 half-waves evidently occurs when the two corresponding curves in Fig. 2 have equal ordinates, i.e., when
From this equation we obtain
Substituting m = 1, we obtain
At this ratio we have transition from one to two half-waves. By taking m = 2 we find that transition from two to three half-waves occurs when
From Eq. (6) the critical value of the compressive stress is
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Steel thin plate: a = 15 mb = 5 mh =50 mmSAP2000 Model