Variable-Stiffness Lattice Midsole for Cushioning and Load Support
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Solution Overview
Problem
Conventional midsole designs in footwear lack optimal distribution of stiffness and cushioning, leading to inadequate support, comfort, and performance, especially under varying loads during activities like walking and running.
Innovation Solution
A 3D fabrication system generates and outputs codes for lattice structures with varying stiffness levels and cavity designs, where a stiffer first lattice structure decelerates load and stores energy, while a softer second lattice structure provides additional cushioning, positioned strategically to enhance user comfort and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a midsole uses uniform stiffness material throughout, then manufacturing is simple, but cushioning and support performance are inadequate under varying loads
Solution Approach 1:
The midsole is segmented into multiple lattice structures with different stiffness levels (first lattice structure with higher stiffness, second lattice structure with lower stiffness) positioned at different locations. This segmentation allows each region to be optimized for its specific function - harder regions for support and softer regions for cushioning - thereby improving overall performance while maintaining a manufacturable modular structure.
Solution Approach 2:
Different regions of the midsole are assigned different material properties and stiffness levels according to local requirements. The first lattice structure with higher stiffness is placed in regions requiring support, while the second lattice structure with lower stiffness is placed in regions requiring cushioning. This local differentiation of properties optimizes performance without requiring complex manufacturing processes.
2Ease of operation
If a midsole uses softer material for cushioning, then comfort is improved, but load support capability deteriorates
Solution Approach 1:
The midsole is divided into functional zones with different stiffness characteristics. Softer second lattice structures provide cushioning for comfort in regions where load is less critical, while harder first lattice structures provide load support in regions requiring strength. This spatial segmentation resolves the contradiction by allowing both soft and hard regions to coexist in the same component.
Solution Approach 2:
The midsole exhibits spatially varying stiffness properties matched to local functional requirements. Areas requiring comfort have lower stiffness lattice structures, while areas requiring load bearing have higher stiffness lattice structures. This local optimization allows the midsole to be comfortable where needed while maintaining strength where required.
3Strength
If a midsole uses harder material for support, then load bearing is improved, but cushioning and comfort deteriorate
Solution Approach 1:
The midsole is segmented into first lattice structures with higher stiffness for load bearing and second lattice structures with lower stiffness for cushioning. This segmentation allows the hard regions to provide necessary support without forcing the entire midsole to be hard, thereby preserving comfort in the softer regions.
Solution Approach 2:
Different stiffness levels are assigned to different locations within the midsole based on local load bearing requirements. Regions requiring high support have harder lattice structures, while regions prioritizing comfort have softer lattice structures. This local quality differentiation allows the midsole to be hard where needed for support while remaining soft where comfort is prioritized.
4Reliability
If a midsole uses complex multi-density lattice structures, then performance is improved, but manufacturing complexity increases
Solution Approach 1:
The lattice structures are designed with adjustable parameters including cell size, wall thickness, and lattice geometry that can be modified to achieve different stiffness levels. By systematically varying these parameters across different regions, the patent achieves performance optimization through parameter control rather than through complex assembly processes, thereby maintaining manufacturing simplicity.
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 combination of lattice structures and cavity design in the midsole offers improved support, comfort, and performance by decelerating load, storing energy, and providing enhanced cushioning, resulting in a lighter and more effective midsole.
Implementation Method 1
the first lattice structure may be compressed and may store the energy while in the compressed state
Implementation Method 2
the cavity may compress prior to the first lattice structure
Implementation Method 3
the first lattice structure may decompress and release the stored energy, which may assist in propelling the user
Data Source
AI summary
According to examples, machine-readable instructions in a computer-readable medium may cause a processor to generate code representing a cavity to be formed in an object, generate code representing a first lattice structure to be formed in the object directly above the cavity, and generate code representing a second lattice structure to be formed in the object in an area adjacent to the first lattice structure, in which the first lattice structure may be stiffer than the second lattice structure. In addition, the processor may output the generated codes, in which a three-dimensional (3D) fabrication system may fabricate the object according to the generated codes.