Sleeper Pad Stiffener Resists Bending Deformation
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Solution Overview
Problem
Existing nonwoven fabric-integrated sleeper pads face issues with maintaining consistent modulus of elasticity and damping over time, leading to track irregularities and reduced service life due to differences in shrinkage between rubber and nonwoven fabric, causing bending deformations and uneven load distribution.
Innovation Solution
A nonwoven fabric-integrated sleeper pad with a rubber pad embedded with a stiffener, such as a lattice-shaped glass fiber, is used to resist horizontal deformation and adjust vertical support stiffness, ensuring flatness and securing an attaching force with the concrete sleeper through a thermal fusion process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rubber pad is integrated with nonwoven fabric through thermal fusion, then the sleeper pad achieves good initial elasticity and damping, but the modulus of elasticity and damping cannot be maintained over time due to differential shrinkage between rubber and nonwoven fabric
Solution Approach 1:
The patent applies local quality by embedding stiffeners at specific locations within the rubber pad (at intervals of 100-300mm) rather than uniformly throughout. These localized stiffening elements counteract the differential shrinkage between rubber and nonwoven fabric in critical areas, maintaining the modulus of elasticity and damping properties over time without requiring uniform reinforcement of the entire pad structure.
Solution Approach 2:
The patent uses composite materials by combining rubber with stiffener elements (such as glass fiber, steel, or composite stiffeners) to create a hybrid structure. This composite approach allows the rubber pad to maintain its elasticity and damping characteristics while the stiffener components prevent deformation and maintain structural integrity during the service life of the sleeper pad.
2Strength
If nonwoven fabric and rubber are bonded through thermal fusion, then strong attachment is achieved, but bending deformations occur due to differences in shrinkage between the two materials
Solution Approach 1:
The stiffeners are strategically positioned within the rubber pad to provide localized structural support that counteracts the bending deformations caused by differential shrinkage. This localized reinforcement maintains the flatness of the sleeper pad surface while preserving the strong thermal fusion bond between the nonwoven fabric and rubber pad.
Solution Approach 2:
The stiffeners are embedded within the rubber pad during the manufacturing process, before the thermal fusion bonding occurs. This preliminary placement ensures that the stiffening elements are already in position to prevent bending deformations as the rubber and nonwoven fabric shrink at different rates during and after the bonding process.
3Force
If the rubber pad is made thicker to increase vertical stiffness, then load distribution improves, but the pad becomes more prone to horizontal deformation and aging
Solution Approach 1:
Instead of increasing the thickness of the rubber pad alone, the patent creates a composite structure by embedding stiffeners within the rubber matrix. This composite approach provides vertical stiffness support while the stiffener elements simultaneously resist horizontal deformations, avoiding the aging and deformation issues associated with thicker rubber pads.
Solution Approach 2:
The patent segments the rubber pad structure by incorporating discrete stiffener elements at specific intervals rather than creating a uniformly thick structure. This segmentation allows the rubber pad to maintain appropriate thickness for load distribution while the distributed stiffener elements collectively provide resistance to horizontal deformation throughout the pad.
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
The solution effectively increases the vertical stiffness and service life of the sleeper pad by resisting bending deformations and maintaining consistent load distribution, enhancing the quality and utilization of the pad-attached sleeper.
Implementation Method 1
the attaching nonwoven fabric is embedded by being pressed toward a surface of concrete placed in a sleeper formwork, and as the placed concrete is cured, the nonwoven fabric-integrated sleeper pad is embedded in the bottom surface of the concrete sleeper
Implementation Method 2
the rubber pad and the nonwoven fabric are integrated by a chemical bonding process as the close contact surface between the nonwoven fabric and the rubber pad is melted and diffused by vulcanization
Implementation Method 3
the close contact surface between the nonwoven fabric and the rubber pad is melted and diffused by vulcanization
Implementation Method 4
one or more stiffeners are embedded in a rubber pad in close contact with the nonwoven fabric... the stiffener resists horizontal deformation of the rubber pad to increase vertical stiffness
Data Source
AI summary
The present disclosure provides, as a sleeper pad for railroad sleepers in which a nonwoven fabric is attached to a rubber pad by a thermal fusion process, a nonwoven fabric-integrated sleeper pad using a rubber pad embedded with a stiffener and methods of manufacturing and constructing the same, which can adjust vertical support stiffness of the rubber pad by the stiffener embedded in the middle of the rubber pad and which can secure the flatness of the rubber pad by resisting bending deformation due to a difference in shrinkage between rubber and nonwoven fabric.