An end effector includes a first portion having a first specific acoustic impedance value, and a second portion having a second specific acoustic impedance value less than the first specific acoustic impedance value. The first portion includes a proximal end segment of the end effector and a distal end segment of the end effector, and the proximal end segment and the distal end segment are composed of a first material. The second portion includes an insert segment of the end effector composed of a second material. The insert segment is located between the proximal end segment and the distal end segment along the longitudinal axis of the end effector. The insert segment functions to bridge or fill the nodal energy gap. A surgical instrument includes a transducer configured to produce vibrations along a longitudinal axis as a predetermined frequency. An ultrasonic blade extends along the longitudinal axis coupled to the transducer. An insert segment or a pad is positioned adjacent to the blade such that it engages the blade when the surgical instrument is in a closed position and generates heat filling the nodal energy gap.