Refillable Pet Container Base Design for Stress Crack Resistance
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Solution Overview
Problem
Refillable PET containers face stress crack failures due to repeated filling and distribution cycles, leading to breaking, bursting, or leaking, which limits their usability to around fifteen cycles before becoming unusable.
Innovation Solution
The design of a refillable container with a base featuring a standing surface and a push-up portion, including a recessed central portion and a linear portion that moves in response to internal pressure, reducing material stresses and surface area, allowing for greater durability and resistance to stress cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If PET containers are reused and refilled multiple times, then productivity increases through container reuse, but reliability deteriorates due to stress crack failures after repeated filling and distribution cycles
Solution Approach 1:
The base is divided into distinct functional zones: a push-up portion with a central portion and a linear portion, each serving specific stress-management functions. This segmentation allows different regions to handle different aspects of stress distribution during filling cycles
Solution Approach 2:
The base design incorporates dynamic response to internal pressure through the push-up portion, which moves in response to pressure changes during filling. This dynamic behavior allows the base to adapt to varying stress conditions throughout the filling cycle, preventing stress concentration that would lead to cracking
2Ease of manufacture
If the base surface area is reduced, then manufacturing efficiency improves, but strength deteriorates due to increased stress concentration
Solution Approach 1:
Different regions of the base are given different properties: the push-up portion is designed to be flexible and responsive to pressure, while the linear portion provides structural support. This local differentiation allows the base to maintain strength with reduced overall surface area by concentrating material where it is most needed
Solution Approach 2:
The base combines different structural configurations in the push-up and linear portions to create a composite structure that optimizes both strength and material efficiency. The combination of recessed central portion and radially extending linear portion creates a composite geometry that resists stress cracking
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 container can withstand thirty-two accelerated test cycles without base stress crack failures, a 30% improvement over industry standards, enabling more refilling cycles without stress crack-related issues.
Implementation Method 1
The linear portion and the central portion are movable towards the first end of the container in response to an internal volume within the container
Data Source
AI summary
A refillable container including a base having a standing surface surrounding a push-up portion. The push-up portion includes a central portion at a center of the base that is recessed inward from a plane extending across the standing surface. A longitudinal axis of the container extends from a first end of the container to a second end through the central portion. A linear portion of the base extends radially outward from the central portion towards the standing surface of the base. The base is configured to reduce stress crack failures.