Manipulation of Weyl Points in Reciprocal and Nonreciprocal Mechanical Lattices

We introduce feedback -measurement technologies to achieve flexible control of Weyl points and conduct the first experimental demonstration of Weyl type I -II transition in mechanical systems. We demonstrate that non-Hermiticity can expand the Fermi arc surface states from connecting Weyl points to Weyl rings, and lead to a localization transition of edge states influenced by the interplay between band topology and the non -Hermitian skin effect. Our findings offer valuable insights into the design and manipulation of Weyl points in mechanical systems, providing a promising avenue for manipulating topological modes in non -Hermitian systems.