DESIGN OF LAMINATES 



6-83 



b. buckling in two half waves 



d. buckling in four half waves 

 _2 



K cr 



20h 



r 2 + 353 + 3h> 



r^ 



(6.51c) 



(6. 51d) 



(6.51e) 



Case 4. All Edges Clamped 



When all edges are clamped, the buckling load is again dependent upon the form assumed 

 by the buckled surface. The basic formula 



P cr ~ k cr 



12 A^ 



has the following 



(6. 50) 



values for k„ 



a. buckling in one half wave 

 2 



k = S- 

 cr q 



3r 2 + X, + 2k 

 r 



(6.51f) 



b. buckling in two half waves 



k 



2 



cr 



160 



l6r 2 + HI + ] t 0vc 

 r 2 



c. buckling in three half waves 



2 



2r^ + 



cr 



h5 



2r 2 + 51 + 10K 



,2 



(6.51g) 



(6.51h) 



d . buckling in four half waves 

 2 " 



cr 



612 



I6r 2 ♦ 1259 + 136K 

 „2 



(6.51i) 



In Cases 3 and 4, the least value of P cr will be the critical value for the plate. 



In order to expedite the work of the designer, Tables 6-4 through 6-15 for mat, woven 

 roving and cloth laminates have been prepared using an electronic digital computer. In 

 setting up the above equations for the computer solution the following assumptions were made: 



