Complex sentence: To simulate the behavior of concrete, there are some analytical stress-strain models and damage indices for confined and unconfined concretes to simulate reinforced concrete structures that make possible without any experimental test to evaluate the stress-strain relationship and damage of confined and unconfined concretes.
Split into simpler sentences: To simulate the behavior of concrete, there are some analytical stress-strain models for confined and unconfined concretes to simulate reinforced concrete structures. They make possible without any experimental test to evaluate the stress-strain relationship of confined and unconfined concretes.