Resonant free platen for vibration testing of test specimens

Abstract

This invention relates to a system for vibration testing of specimens usingn electro-dynamic shaker. It overcomes the various undesirable consequences which attend the existing technology and methodology, which uses a constant thickness flat plate platen, by using an inverted, truncated pyramid type of platen, with both the base and top of square-rectangular-parallelpiped shapes, attached to a cylindrical shaker head. The outer portion of the platen has a very low mass and the section modulus is very high at the line of bending thereby increasing the resonant frequency of the platen while lowering the total weight of the platen, because there is less mass around the perimeter of the platen. The optimum shape of the pyramid is determined by a means which can be expedited by use of the computer program.

What is claimed is: 
     
       1. A resonant free platen system for vibration testing of test specimens, comprising: a cylindrical shaker head, an inverted truncated pyramid platen having an area for receiving specimens to be tested and coupled to said cylindrical shaker head, and means for vibrating said shaker head. 
     
     
       2. A resonant free platen system for vibration testing of test specimens as recited in claim 1, wherein said truncated pyramid platen has a form comprising a truncated square pyramid with its larger base joined to a truncated cube, all as one piece. 
     
     
       3. A system as in claim 1 wherein said truncated pyramid has respectively a top square cross-sectional area and a bottom square cross-sectional area of smaller side dimension, which said bottom and top area are plane parallel to one another. 
     
     
       4. A system as in claim 3 wherein test specimens are fastened at said top area, and the shaker head attached at said bottom area. 
     
     
       5. A system as in claim 4 wherein said platen is formed of aluminum. 
     
     
       6. A system as in claim 4 wherein said platen is formed of magnesium.