Mast Assembly Foundation Design for Impact Energy Absorption
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Solution Overview
Problem
Mast arrangements along roads, designed to yield upon vehicle impact to prevent damage, often detach and cause secondary collisions due to inadequate energy absorption, leading to increased costs with thicker walls as a solution.
Innovation Solution
A mast arrangement with a foundation having an inner diameter larger than the mast at its upper end, allowing for plastic deformation and energy absorption without detachment, combined with a conical taper and an annular flange plate for enhanced stability and energy dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the wall thickness of the mast is increased to prevent detachment and reduce energy absorption, then the mast becomes more stable and less likely to detach, but the cost increases considerably
Solution Approach 1:
The foundation is divided into an upper portion with a first inner diameter and a lower portion with a second inner diameter. This segmentation allows the mast to have different clearance conditions at different heights, enabling plastic deformation in the upper portion while maintaining secure anchorage in the lower portion, thus preventing detachment without requiring increased wall thickness
Solution Approach 2:
The foundation has non-uniform inner diameter along its height, creating different local conditions: a larger clearance in the upper portion for energy absorption through plastic deformation, and a smaller clearance in the lower portion for secure anchorage. This local differentiation resolves the contradiction between allowing deformation and preventing detachment
2Loss of energy
If the wall thickness of the mast is increased to absorb more impact energy, then the energy absorption capacity increases, but the cost increases considerably
Solution Approach 1:
The conical portion of the foundation with larger inner diameter acts as a pre-designed deformation zone that allows the mast to undergo controlled plastic deformation during impact. This beforehand prepared space enables energy absorption through deformation rather than requiring thicker walls, reducing manufacturing costs while maintaining energy absorption capacity
3Loss of energy
If the mast is designed to detach upon impact to absorb energy, then energy absorption improves, but the mast may be thrown far away causing secondary collisions
Solution Approach 1:
The foundation is segmented into upper and lower portions with different inner diameters. The upper portion allows controlled plastic deformation for energy absorption, while the lower portion provides secure anchorage that prevents complete detachment and throwing of the mast, thus eliminating secondary collision risks
Solution Approach 2:
The larger clearance in the upper foundation portion converts the potentially harmful complete detachment into a beneficial controlled plastic deformation. The mast deforms in a controlled manner to absorb energy while remaining anchored, transforming the harm of detachment into the benefit of energy absorption without secondary collisions
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Prevents mast detachment and secondary collisions by absorbing impact energy through plastic deformation, reducing kinetic energy and injury risk to vehicle occupants while maintaining structural integrity.
Implementation Method 1
the mast can deform plastically in this free space without tearing off. The originally circular cross-section of the mast is compressed during the collision, absorbing a significant part of the impact energy
Implementation Method 2
The friction between the inside of the foundation and the mast holds it securely
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
The mast assembly (1) has a tubular shaped mast (3), which is used in a foundation (2), where the inner diameter of the foundation in the region of its upper end, is larger than the diameter of the mast in the region of upper end of the foundation. An annular space is formed between the outer side of the mast and the inner side of the foundation, where the top of the foundation is mounted on an annular flange plate. The foundation has a reinforcement element made of steel, where the mast is made of fiberglass reinforced plastic.