“…In the OSPD theory, the force vector state is determined by the collective deformation of the family of material points x . The equation of motion of the dual‐horizon OSPD model is given as where ρ ( x ) is the mass density, a ( x , t ) is the acceleration vector, and u ( x , t ) is the displacement vector. V p is the incremental volume associated with node p . is the prescribed body force vector, and is the force vector state; if the material is simple (a simple material in OSPD is defined as one in which the force state depends only on the deformation state), the force state does not depend explicitly on time t .…”