The aim of this research is to design a prototype of a male dummy chest for motorcycle crash tests. The primary criteria discussed in this study are based on the unique features of Thai ergonomic body sizes with an age range of the highest fatal rate and the fundamental design of the Hybrid III 50th percentile male crash test dummy. A comprehensive experimental study of crash behavior of the prototype undergoing axial compressive loading is performed using the mutual procedure of cadaveric chest testing. For design criteria the largest chest deflection of 80 mm the maximum acceleration of 38.47g and the absorbed energy of 178.369 Joules are considered in the experiment. The obtained results show a good agreement with the experimental data of other researches in which the capability of the energy absorption depends on impact velocities. In addition the energy absorption capability of this prototype can accurately assess an injury level under AIS 3+. For this reason the first prototype of a male chest dummy is particularly suitable for an assessment of a lower serious injury level in a motorcycle crash test.

The aim of this research is to create the center of mass testing machine for vehicles with maximum mass 3000 kilograms. By the performance of this machine is able to determine the center of mass 3 axis by horizontal longitudinal and vertical. On the other hand the verities of mass from 50 to 100 kilograms and the several of weight distribution at horizontal and longitudinal are applied to the condition of testing for reasonable to the position of the center of mass. The result of research discovered to the performance of center of mass tester was activated following to test conditions. Furthermore the weight distribution at longitudinal was the highest effect to the horizontal center of mass. By the way the value of weight distribution at horizontal is more effects to the longitudinal center of mass. Moreover increasing of mass was impact to the vertical center of mass and it’s independent to the position of weight distribution.

The aim of this research is to study the varieties of weight density distribution affect to the center of mass and vehicle stability. The weight density distribution tester was designed and changed the position of mass. Base on the center of mass is main points of vehicle stability. On the other hand FMCSA standard was applied to field test for considering of the brake performance and vehicle stability. The results of research discovered to the mass distribution on longitudinal plane are affected to the center of mass and absolutely influence at the right wheel on the front axle. In term of the braking performance it’s depends on the lateral mass distribution especially the center position of mass installed on longitudinal and horizontal plane and close up on the front axle (Y2). For the vehicle stability results the position (Y2) is the highest influence for yaw rate and sideslip. Otherwise the position (Y3) or the position of mass installed on longitudinal plane and nearly at the left wheel on the rear axle. Additionally wheel lock-up condition was appeared on the front axle only. Because the behavior of weight distribution on the front axle was decreased lead to mass distribution on longitudinal plane.

The aim of this research is to study the brake proportional affected to vehicle stability. Braking performance and vehicle stability testing are the main of research purposes. Otherwise learning research center and new researcher in automotive engineering are the minor research objectives. The results of research discovered to the braking performance depend on driver behavior. By the minimum deceleration was appeared on the non-proportion in front axle with braking ratio 0:100. In term of vehicle stabilities yaw and pitch moment are normally occur by the driving behavior. But the sideslip is an absolutely effect to vehicle handling. With the braking ratio 100:0 there is the highest risk for controlling a vehicle cause of the wheels were locked-up condition in the rear axle. Therefore the value of the sideslip was exceeded with the criteria. Furthermore these project researches were got the learning research center and the new researcher in automotive engineering field.

Braking system is the main of safety for motor vehicle. It uses to slow down or stop of vehicle movement. Normally braking system can not to adjustable in the recently. The brake efficiency depends up on to 3 factors by the perfection of brake equipment friction coefficient of road surface and the brake proportional. The factor of the perfection of brake equipment and friction coefficient of road surface can not be control. But in case of the brake proportional can be set up to suitable. In the other hand if the brake ratio is unsuitable the driver may be risk to danger from the loss of vehicle control. From this reason the aim of project is to study of the brake proportional affected to vehicle control. By the test condition consist of 2 cases: braking performance testing and vehicle stability testing. In case of braking performance testing is consider to deceleration braking distance and time of braking. For the vehicle stability testing is determined with yaw angle pitch angle sideslip angle and wheel lock up condition. However the bolt of testing is the road test and using the FMCSA standard for the testing guideline. The result of the braking performance testing shown the maximum deceleration was appeared on brake proportional 80:20. But the braking distance and time of braking are least because of the non-continuously of deceleration from the driver. Therefore the braking distance and time of braking depend on the continuously of deceleration. In term of vehicle stability testing discovered to the each of brake proportional are risk to danger for the driver especially on the 100:0 because of the value of sideslip angle is more than the critical point and the rear axle is lock up.