In transportation machinery, the steel structure of semi-trailer and full-trailer is the same. The method approximates the crane design. Because of the road conditions in our country. The dynamic load factor used in the design is generally 1.8-2.5.

The fatigue coefficient is generally 1.2-1.4. The trailer travels on the dirt road at a speed of 40 km/h. The dynamic load factor can reach: 3-4. Therefore, different steel structures should pay attention to their characteristics: In the calculation of the trailer:

1. Large dynamic load;

The stress concentration of steel structural members is very significant.

3. Obvious low-cycle fatigue.

Calculation method of trailer steel structure:

1. The static stress value multiplied by the dynamic load factor is less than the allowable stress value.

2. The ratio of the material’s yield strength value to the static stress value is greater than the allowable safety factor value.