Rail Actuator Array for Moving Load Simulation

Solution Overview

Problem

Current methods fail to effectively simulate the dynamic loading process of a moving train in rail transportation, which is crucial for understanding the dynamic stability and vibration effects on rail and subgrade structures, especially at high speeds, due to differences in loading characteristics compared to fixed-point cyclic loading.

Innovation Solution

A simulated loading method and apparatus that uses a verified train-rail-subgrade theory model to distribute fastener force along the train's movement direction, expressed through a Gauss function, and applies this force as a time-varying load excitation to actuators positioned along the rail, simulating the moving load of a whole train without requiring a real train model.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional fixed-point cyclic loading is used, then the loading setup is simple, but it cannot accurately simulate the moving load characteristics of train on rail

Engineering Contradiction:

Improvesimulation accuracy of moving loadVSAvoidloading apparatus complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the continuous moving train load into discrete segments by placing multiple actuators at different positions along the rail. Each actuator applies load independently, simulating the distributed nature of train wheels on the rail. This segmentation allows accurate representation of moving load characteristics while maintaining manageable system complexity through modular actuator units.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent creates a simplified copy of the train loading system using actuators that replicate the force application patterns of actual train wheels. Instead of using a real train, the system copies the essential loading characteristics through controlled actuator excitation, achieving accurate simulation without the complexity of full-scale train testing.

Inventive Principle:

Principle #26Copying

2Measurement precision

If a real train model is used for testing, then the moving load effect can be accurately captured, but the test setup becomes complex and resource-intensive

Engineering Contradiction:

Improvedynamic performance measurement accuracyVSAvoidtest setup complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent creates a simplified copy of the train loading system using actuators that replicate the force application patterns of actual train wheels. Instead of using a real train, the system copies the essential loading characteristics through controlled actuator excitation, achieving accurate simulation without the complexity of full-scale train testing.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent replaces the complex mechanical system of a real train with an actuator-based loading system. The actuators, controlled by computer systems, substitute for the mechanical mass and motion of actual train vehicles, maintaining measurement accuracy while dramatically reducing test setup complexity and resource requirements.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Speed

If high-speed train operation is studied, then the speed effect and Mach effect can be investigated, but the required test infrastructure becomes extremely complex

Engineering Contradiction:

Improvetrain speed simulation capabilityVSAvoidhigh-speed test infrastructure complexity

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The patent replaces the complex mechanical system of a real train with an actuator-based loading system. The actuators, controlled by computer systems, substitute for the mechanical mass and motion of actual train vehicles, maintaining measurement accuracy while dramatically reducing test setup complexity and resource requirements.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs dynamic loading through actuators that can rapidly adjust their position and applied force to simulate high-speed train conditions. The system uses dynamic excitation patterns and time-varying load applications to capture speed effects and Mach effects without requiring actual high-speed train operation, thereby avoiding the need for complex high-speed test infrastructure.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS9785730B2Simulated loading method and apparatus for moving load of whole train in rail transportation

Publication Date: 2017.10.10 ZHEJIANG UNIV

AI summary

The present invention discloses a simulated loading method and an apparatus for moving load of a whole train in rail transportation. Multiple actuators are arranged above rail sleepers along rail direction. The rail is cut into separate rail segments, which are connected to rail sleepers via fastening systems. Based on a verified train-rail-subgrade theory model, the distribution of fastener force under the movement of a train bogie can be obtained. A simplified expression of this solution can be acquired by Gauss function fitting considering the train axle load, which is used as the input load of actuators. Each actuator performs the same dynamic excitation sequentially with a time interval along the train moving direction. Therefore, moving load of different vehicle types at different train speeds can be simulated. The present invention provides a reliable and convenient test method and an apparatus for research of developing infrastructures of rail transportation.