;j8G 



Professor Ernest G. Coker 



Tab],k III. 



[Feb. 18, 



in Fig. 6, and the principal stresses deduced from them are given in 

 Fig. 7. They show that the tensile stress at the cross section reaches 

 a high value, while below the rivet an even greater compression stress 

 is produced. The measurements of radial stress along the sections 

 chosen give marked compression close to the rivet, and it is worthy 

 of note that they are very nearly zero at the outer boundaries of the 

 plate, results which confirm the general accuracy of the measurements. 

 Other measurements of a similar kind show that the action of a rivet 

 produces an intense stress at the hole, sometimes reaching five times 

 the stress in a full plate. In a transparent model this is often 

 accompanied by permanent overstress and local yielding, which latter 

 tends to equalize the stress in the material. 



Blocks in Compression. 



A problem of considerable importance in practical engineering, 

 is the distribution of stress in a rectangular block subjected to pure 

 compression. This case occurs in the testing of materials when 

 equal and oppositely directed loads are applied to the parallel faces 

 of a short rectangular block, of a material like stone, brick, or concrete, 

 to give a compressive stress as uniformly applied as is possible. 



The manner in which the load is applied to the end faces of 

 such a rectangular l)lock, is known to exert an influence upon the dis- 

 tribution of stress and strain, and to obtain consistent results the end 



