2. An Investigation into the Failure of Belly Dump Trailers
Mr Peter Airey
BE GradDipAdmin FIEAust CPEng RPEQ
Managing Director - Airey Taylor Consulting Engineers & Scientists Chairman – Advanced Substructures Ltd

3. Dump Truck Arrangement
Product Mass = ~70,000kg/trailer = 211,000kg total
Dump Truck Mass = 16,000kg
Dolly Mass = 3,500kg

4. Typical Failure

5. Investigation Methodology
Max. Horizontal
Design Load = 320 kN
Mass Flow, Squad Containers: Geometry Type C2

6. Stress Modelling & Analysis
SAP2000 Static and Dynamic Finite Element Analysis
Quantify working stresses in trailer body
Particular focus on welded arm connections

7. Stress Modelling & Analysis
Combination of principal stresses evaluated using “Von Mises” criterion: 𝜎 1 2 − 𝜎 1 𝜎 2 + 𝜎 2 2 ≤ 𝜎 𝑦 2

8. Stress Modelling & Analysis
Figure 4
Ed = 1.2G + 1.5Q (Fig. 4)
Stresses limited further at welded connections to prevent fatigue failure AS/NZS – Cl & 11.6:
Detail Category 56
Fatigue Stress = 90 Mpa (106 cycles)
Maximum Von Mises Stress of 320MPa at arm connection and 460MPa at access hatch

9. Conclusions Limiting fatigue stresses exceeded in multiple locations
Problem locations determined via analysis correlated with areas of repeat failure
Design-generated issue
Mechanical design of such scale requires qualified structural design input