EFFECT OF UV- RADIATION ON FATIGUE BEHAVIOUR OF NATURAL COMPOSITE MATERIALS

The UV-radiation effect on fatigue behaviour of natural composite materials was investigated experimentally. The egg shell - polyester, date nuclei - polyester, and palms leaf - polyester were used in this experiment using (20 %, 40%, and 60%) volume fraction. The samples were affected on UV- radiation for three different times (100 hour, 300 hour, and 500 hour). The mechanical properties of natural composite samples (with and without UV-radiation) were found. The fatigue test for natural composite samples was done. The resultant shows that, the increasing volume fraction causes increasing of endurance stress of natural composite materials. The palm leaf – polyester samples have mechanical properties better than egg shell – polyester and date nuclei – polyester samples. The increasing time of UV- radiation causes reduction in endurance and tensile stresses. The greatest and smallest reduction in stress endurance due to UV- radiation occurs in palm leaf and nuclei natural samples. The date nuclei natural composite material has good resistance to UV- radiation under fatigue effect.