Mechanical device for prestressing of carbon fiber reinforced polymer (CFRP) sheets

Abstract

A mechanical device was invented for prestressing of carbon fiber reinforced polymer (CFRP) sheets. Significant features of this device are that the CFRP sheets are directly anchored to the mechanical device itself, the prestressing forces are applied with a manual torque wrench without the need for power operated hydraulic jacks and the prestressing transfer is accomplished under slow strain rates. Experimental investigation clearly indicates that the device was efficient in applying prestressing to the CFRP sheets and prestress losses during stressing were maintained at a minimum.

1 . The mechanical device was capable of anchoring and prestressing the CFRP sheets up to at least 40% of the ultimate strength of CFRP sheet. 
     
     
         2 . The prestressing forces were indirectly applied manually by using threaded rods without the need for hydraulic jacks and can be determined through the strain readings from strain gages attached to the CFRP sheets. 
     
     
         3 . In field applications, one may control the prestressing force by measuring the vertical displacement of the CFRP sheets.