The document discusses reducing stress concentration in polymer composites by using different materials for inbuilt rectangular patches near discontinuities like holes. Testing was conducted on glass fiber reinforced polymer (GFRP) composites with rectangular patches made of either glass fiber or carbon fiber. Results showed that using a stronger carbon fiber material for the patch reduced the stress concentration factor by 4% compared to a glass fiber patch, as the carbon fiber is more compatible and stronger than the base glass fiber reinforcement. Finite element analysis of a specimen with a glass fiber patch matched experimental results closely. In conclusion, the choice of patch material can significantly influence stress concentration at discontinuities.