A new designing concept to realize multifunctional structural material systems without using sophisticated functional
materials was proposed and demonstrated in this paper. The concept can be explained as follow: There exist a couple of
competitive structural materials which normally compete with each other because of their similar and high mechanical
properties, and they tend to have another property which is different from each other or opposite among them. So if they
are combined together to make a composite, the similar property, normally high mechanical property, can be maintained,
and the other dissimilar property conflicts with each other, which will successfully generate a functional property
without using any sophisticated functional materials. According to this concept, two examples, that is, a CFRP/Al active
laminate and a Ti fiber/Al multifunctional composite were made and it was successfully demonstrated.