دراسة تاثير الكسر الحجمي على بعض الخواص الميكانيكية الديناميكية لمتراكبات بوليميرية دقائقية

The study was carried out by reinforcing the resin matrix material which was (unsaturated polyester)by using alumna powder (Al2o3)with particle size (75)μm to prepare composite materials with different volume fractions(3%,7%,10%) by using hand Lay -up method. Some dynamic mechanical properties was studied of the prepare composite samples by using ultrasonic technique as a nondestructive testing After that the transite time of the ultrasonic waves which passes through the composites was measured, from this measurement the compressional and shear velocity was calculated and from these velocities som of the dynamic mechanical properties was calculated, these properties included dynamic Young’s modulus(Ed),Shear modulus(G),dynamic Poisson's ratio(µ),The dynamic mechanical properties were studied with respect to volume fraction and density .