<p>High-speed train brake pads typically feature multiple friction blocks and a triangle support structure to manage rapid frictional heat dissipation. However, friction-induced stick–slip vibration (FISSV) can occur due to strong frictional interactions and low train speeds, which may destabilize the braking system and compromise safety. To mitigate this issue, we developed two structural designs (positive and inverted triangle supports) for the friction block in the brake pads of Chinese high-speed trains. FISSV simulation tests were conducted on a self-developed multifunctional friction and wear testing device. A multi-degree-of-freedom numerical model was established, and nonlinear dynamic simulations were performed to analyze the FISSV characteristics and nonlinear behavior of the friction system under different friction block and triangle support arrangements. The results show that these structural configurations significantly influence FISSV, with each support design affecting the system’s dynamics in distinct ways. Notably, the positive triangle support resulted in slightly larger displacement during stick–slip motion compared to the inverted triangle support. During the slipping phase, the inverted triangle support generated higher intensity and frequency of friction-induced vibration and noise (FIVN). In terms of nonlinear dynamics, both support structures transitioned from chaotic states to periodic motion as the friction disc speed increased. Friction blocks with larger friction radii exhibited more complex nonlinear behaviors. The positive triangle support demonstrated a smaller chaotic state range and lower vibration intensity, making it more effective in reducing FIVN. Overall, the study highlights the critical impact of triangle support structure design on FISSV characteristics, with the positive triangle support offering advantages in minimizing noise and vibration.</p>