The National Research Institute of Mechanical Engineering plans to organize the Institute-level Doctoral Thesis Evaluation Council for doctoral candidate Phí Hoàng Trình in early January 2026. The Institute hereby publishes the information on the doctoral thesis of the candidate as follows:

Full name of doctoral candidate: Phí Hoàng Trình

Supervisory team: Assoc. Prof. Dr. Nguyễn Thanh Quang and Assoc. Prof. Dr. Hoàng Văn Gợt

Field: Mechanical Engineering - Code: 9520103

Training institution: National Research Institute of Mechanical Engineering - Ministry of Industry and Trade

Thesis title: "Study on the influence of some seat structure parameters on the vibration of seated occupants in vehicles".

Summary of new findings of the thesis

1. Scientific significance:

- The study establishes the relationship between certain technical parameters in the Road - Vehicle - Seat - Occupant system with variations in the structure of passenger seats in automobiles.

- Combines two solution methods from Lagrange type II theory and finite element theory to solve the overall model: Road - Vehicle - Seat - Occupant.

- Analyzes seat structure with parameters such as stiffness, damping, frame structure, springs, welds, connecting pads, backrest pads, etc. Selects the stiffness and damping parameters of the seat base as representative by varying the seat base stiffness when adding intermediate pads. The results demonstrate the influence of seat structure on occupant vibration when using four different pad materials.

- Conducted experiments on an actual Toyota Vios 5-seat vehicle to establish the relationship between input parameters: road roughness from sinusoidal and pulse-shaped speed bumps, and random road surface ISO 8608; vehicle speed; materials of vibration-absorbing pads. Output parameters: floor vibration acceleration and frequency, vibration acceleration on the human body according to RMS values corresponding to ISO 2631-1.

2. Practical significance

- The results of the thesis can be applied as reference material for research, teaching, and design of seats in certain vehicles suitable for Vietnamese conditions.

- The study establishes the relationship between certain technical parameters in the Road - Vehicle - Seat - Occupant system with variations in the stiffness and damping of automobile seat structures.

- Determines vibration at three positions on the seated human body: buttocks, chest, and head as representative locations, which can be applied to all body positions.

3. New contributions of the thesis

- The thesis has developed a set of parameters for the seat structure of vehicles with independent suspension systems, suitable for human physique and road conditions in Vietnam.

- Studies the influence of seat structure on users, aiming to enhance comfort and convenience suitable for operating conditions in Vietnam.

- Developed a Road - Vehicle - Seat - Occupant model using modern simulation tools, allowing investigation of the impact of road roughness on human body vibration, thereby determining the stiffness and damping of vibration-absorbing pad materials to reduce excitation forces on seated occupants and ensure health. The research can be extended for analysis of all seat structural components.

For the detailed content of the thesis of candidate Phí Hoàng Trình, please see here