Rail Vehicle Impact Absorber Radial Force Distribution

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Solution Overview

Problem

Railway vehicles face challenges in absorbing impact energy during collisions, as increasing the crushing load to enhance energy absorption leads to higher crushing peak loads, which can cause significant impact shock to crew and passengers.

Innovation Solution

A shock absorbing device with a hollow structure featuring an inner and outer polygonal plate connected by ribs, where a front member with a smaller cross section is positioned coaxially to absorb impact forces radially, preventing the load from acting on the entire surface and reducing the crushing peak load.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the crushing load is increased to enhance energy absorption, then the energy absorption capability is improved, but the crushing peak load increases causing significant impact shock to crew and passengers

Engineering Contradiction:
Improveenergy absorption capabilityVSAvoidimpact shock to crew and passengers
Core Design Contradiction:
Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The front member is divided into multiple crushing sections (first, second, and third crushing sections) with different cross-sectional areas arranged in sequence along the longitudinal direction. This segmentation allows the impact load to be absorbed in stages, with each section crushing sequentially to reduce the peak load while maintaining total energy absorption capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sections of the front member are designed with different local properties - the first crushing section has a smaller cross-sectional area to absorb initial impact with lower peak load, while the second and third crushing sections have progressively larger cross-sectional areas to absorb remaining energy. This local differentiation optimizes both peak load reduction and total energy absorption.

Inventive Principle:
Principle #3Local quality

2Reliability

If a strong structure is disposed to prevent penetration of flying objects, then the protective capability is improved, but the impact shock absorption capability deteriorates

Engineering Contradiction:
Improveprotective capability against flying objectsVSAvoidimpact shock absorption capability
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The front member is designed with dynamic crushing sections that progressively deform under impact load, transitioning from a rigid protective structure to a dynamic energy-absorbing structure during collision. The multiple crushing sections are designed to collapse sequentially, providing both initial protection and progressive energy absorption.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The cross-sectional area parameter of the front member is varied along its length, with smaller sections at the front and progressively larger sections toward the rear. This parameter change allows the structure to provide adequate protection while enabling controlled deformation for energy absorption, as the varying cross-section determines the crushing sequence and load distribution.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the cross-sectional area of the front member is increased to enhance protective capability, then the protection against penetration is improved, but the crushing peak load increases

Engineering Contradiction:
Improveprotective capabilityVSAvoidcrushing peak load
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The front member is segmented into multiple crushing sections with different cross-sectional areas arranged in sequence. This segmentation allows the protective function to be distributed across multiple sections rather than requiring a single large cross-section, thereby reducing the peak crushing load while maintaining overall protective capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of increasing protection by enlarging the cross-sectional area in two dimensions, the solution transitions to the longitudinal dimension by arranging multiple crushing sections of varying sizes along the length of the front member. This dimensional transition allows adequate protection through sequential crushing while keeping individual cross-sectional areas small enough to limit peak loads.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

This design allows for gradual crushing initiation, reducing the crushing peak load and effectively relieving impact shock on crew and passengers by distributing the force radially, thereby enhancing safety during collisions.

Implementation Method 1

When impact force is applied to the front member, prior to crushing of the absorber, the front member experiences, while maintaining its central axis along the direction in which impact load acts, crushing that penetrates into an inner part of the inner plate from where the outer border of the front member and the end face of the inner plate cross each other for causing the impact force to act on the inner plate in a radial direction from its central axis.

Methodology Applied
Scientific EffectImpact force: Impact Force

Implementation Method 2

the front member experiences, while maintaining its central axis along the direction in which impact load acts, crushing that penetrates into an inner part of the inner plate

Methodology Applied
Scientific EffectDeformation: Deformation

Data Source

PatentEP3216669B1Rail vehicle equipped with impact-absorbing device
Publication Date: 2019.03.13 HITACHI LTD
  • EP3216669B1 patent drawingFigure 1
  • EP3216669B1 patent drawingFigure 2
  • EP3216669B1 patent drawingFigure 3

AI summary

An absorber (10) is a hollow structure that extends in a direction in which impact load acts and includes an inner plate (14) of polygonal cross section, an outer plate (12) of polygonal cross section, and a plurality of ribs (16) connecting the inner and outer plates along the direction in which the impact load acts. An outer plate (22) of a front member (20) of polygonal cross section is mounted in front of the absorber (10) to be substantially coaxial with the absorber (10). When viewed in the direction in which the impact load acts, the outer plate (22) of the front member (20) and the inner plate (14) of the absorber (10) are disposed to cross each other. When impact force is applied to the front member (20), prior to crushing of the absorber (12), the front member (20) experiences, while maintaining its central axis along the direction in which the impact load acts, crushing that penetrates into an inner part of the inner plate (14) from where the outer plate (22) and the inner plate (14) cross each other for causing the impact force to act on the inner plate in a radial direction from its central axis. In this way, the load is prevented from acting on a whole surface of the absorber at a time in a collision, whereby a crushing peak load can be lowered, and the impact shock can be relieved.