# Research on Experimental Validation and Prevention Strategies for Pin Shaft Failure in Concrete Pump Trucks

## TL;DR

This study investigates why pin shaft failures happen in concrete pump trucks and suggests adjusting the mounting angle to prevent such accidents.

## Contribution

The study identifies a high-stress zone related to the oil cylinder axis as a cause of pin shaft failure and proposes a prevention strategy.

## Key findings

- Pin shaft failure is linked to improper mounting angles near the oil cylinder axis.
- High-stress zones are symmetrically distributed around the oil cylinder axis and do not change with rotation.
- Adjusting the mounting angle away from the high-stress zone can prevent failures.

## Abstract

This study focuses on the pin shaft failure accidents occurring during the construction of concrete pump trucks and hypothesizes that the accidents are caused by improper installation of the pin shaft mounting angle (defined as the angle between the oil passage axis and the horizontal plane). First, the actual operating conditions were simplified to design an equivalent test, through which the stress distribution of the pin shaft under the 360° rotation condition was measured and understood. Then, simulation analysis was conducted to verify the stress concentration phenomenon under different pin shaft mounting angles. The results show that the pin shaft mounting angle at the accident site falls within the high-stress zone centered on the oil cylinder axis, verifying the hypothesis. In addition, the high-stress zone of the pin shaft does not change with the rotation angle of the pin shaft; it is only related to the position of the oil cylinder axis and distributed symmetrically around the oil cylinder axis. Therefore, to prevent the pin shaft failure accidents, the mounting angle of the pin shaft can be adjusted to keep it away from the high-stress zone near the oil cylinder axis.