Bus Skeleton Stiffening Plate Node Reinforcement

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Solution Overview

Problem

Current bus skeleton structures face instability issues during accidents, particularly due to the high manufacturing costs and durability concerns associated with multiple welds in confined spaces, which can affect the resilience of the skeleton construction.

Innovation Solution

The use of flat reinforcement plates that bridge nodes in the skeleton construction, supported by tube profiles, providing additional stability and support through welding or other connection methods, while reducing the reliance on extensive welding and incorporating weight-saving recesses in the stiffening plates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If multiple welds are used to connect tubular profiles at nodes, then the structural strength is improved, but the manufacturing complexity and durability are worsened due to high density of welds in confined spaces and repeated heating affecting material fatigue

Engineering Contradiction:
Improvestructural strengthVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

A stiffening plate is introduced as an intermediary element between the tubular profiles at the node. The plate connects to multiple tubular profiles through separate welds, distributing the connection points and reducing the density of welds in any single confined space. This mediator approach allows the structure to achieve the required strength without the complexity and durability issues of direct multi-weld connections at the node center.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If multiple welds are used to reinforce nodes, then the structural stability is improved, but the material fatigue and durability are worsened due to repeated intense heating in the welding area

Engineering Contradiction:
Improvestructural stabilityVSAvoidmaterial durability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The connection at the node is segmented into multiple separate weld joints between the stiffening plate and individual tubular profiles, rather than using multiple welds at the same location. This segmentation distributes the thermal impact and prevents repeated intense heating of the same material area, thereby maintaining structural stability while improving material durability and reducing fatigue.

Inventive Principle:
Principle #1Segmentation

3Stability of the object's composition

If stiffening plates with extensive coverage are used to reinforce nodes, then the structural stability is improved, but the vehicle weight is increased

Engineering Contradiction:
Improvenode stabilityVSAvoidvehicle weight
Core Design Contradiction:
Stability of the object's compositionVSWeight of moving object

Solution Approach 1:

The stiffening plate is designed with locally optimized geometry, featuring angled edges that provide maximum reinforcement exactly where needed at the node, while reducing material in areas where less support is required. The plate's shape and thickness are varied locally to achieve the necessary structural stability without adding excessive weight to the overall vehicle.

Inventive Principle:
Principle #3Local quality

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

Enhances the stability and durability of the bus skeleton structure by distributing stress more evenly and reducing the impact of welding on material fatigue, thereby improving the overall resilience and reducing manufacturing costs.

Implementation Method 1

distributing stress more evenly and reducing the impact of welding on material fatigue

Methodology Applied
Scientific EffectStress distribution:

Implementation Method 2

incorporating weight-saving recesses in the stiffening plates

Methodology Applied
Scientific EffectWeight reduction through material removal:

Data Source

PatentEP2767459B1Frame structure for the superstructure of a commercial vehicle
Publication Date: 2019.05.29 MAN TRUCK & BUS SE
  • EP2767459B1 patent drawingFigure 1
  • EP2767459B1 patent drawingFigure 2
  • EP2767459B1 patent drawingFigure 3

AI summary

Frame structure for the construction of a commercial vehicle, in which several tubular profiles (1; 11; 5) meet at an angle to each other at a node (2) and are connected to one another. A flat stiffening plate (3) bridges the node (2), the outer edge region (4) of the stiffening plate (3) being angled towards the individual tubular profiles (5). At least in the outer edge region (4) of the stiffening plate (3), a recess (6; 8) is arranged which fits snugly against the tubular profile (1; 11; 5) and is attached to the tubular profile (1; 11; 5).