Plastic Container Varying-Depth Ribs for Deformation Resistance
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Solution Overview
Problem
Plastic containers face challenges in maintaining structural integrity under stress, particularly during shipping and handling, due to increased demands from removing auxiliary packaging, which leads to deformation and failure under bending, leaning, and stretching.
Innovation Solution
The design incorporates varying depth ribs that transition smoothly around the bottle circumference, combining flattened, middle, and deep sections to distribute forces, providing hoop strength and resistance to bending, leaning, and stretching, while using less resin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If plastic containers use thinner walls to reduce material usage and weight, then transportation and manufacturing costs decrease, but structural integrity and resistance to deformation under stress worsen
Solution Approach 1:
The container wall is segmented into multiple ribs (first ribs and second ribs) with varying depths. The first ribs have a first depth and the second ribs have a second depth greater than the first depth, creating a segmented structural framework that provides strength while using less material overall. This segmentation allows the container to maintain structural integrity with reduced wall thickness.
Solution Approach 2:
Different portions of the container wall have different rib depths tailored to local stress requirements. The second ribs with greater depth are positioned in areas requiring higher strength, while the first ribs with lesser depth are positioned where less strength is needed. This local variation in rib depth optimizes material distribution, providing enhanced strength where required while reducing overall material usage.
2Loss of substance
If auxiliary packaging is removed to reduce packaging material and cost, then packaging simplicity and cost decrease, but stress on individual bottles increases leading to deformation and failure
Solution Approach 1:
The container is pre-designed with a reinforced rib structure before shipping and handling occur. The varying depth ribs create a preemptive strengthening framework that anticipates and resists the stresses of film-only packaging conditions. This preliminary structural preparation allows the container to withstand handling stresses without auxiliary packaging support.
Solution Approach 2:
The container employs a composite rib structure combining first ribs and second ribs of different depths within the same wall. This composite approach creates a multi-level reinforcement system that provides enhanced resistance to bending, leaning, and stretching forces, improving reliability under the increased stress conditions caused by removed auxiliary packaging.
3Ease of manufacture
If uniform depth ribs are used throughout the container wall, then manufacturing simplicity is maintained, but structural efficiency and material distribution are suboptimal
Solution Approach 1:
The rib structure utilizes parameter changes by varying the depth parameter of ribs at different positions around the container. The first ribs have a first depth parameter and the second ribs have a second depth parameter greater than the first. This parameter variation optimizes structural efficiency and material distribution while remaining manufacturable through standard blow-molding processes.
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 design achieves a balance of strength and rigidity, resisting deformation and maintaining shape under pressure, thus reducing material usage while ensuring ease of processing and packaging.
Implementation Method 1
PET has viscoelastic properties of creep and relaxation. As a plastic, PET and other resins tend to relax at temperatures normally seen during use. This relaxation is a time dependent stress relieving response to strain.
Implementation Method 2
This relaxation is a time dependent stress relieving response to strain. Bending can provide exaggerated strains over what would be seen in tensile loading. Due to exaggerated strains, the relaxation in bending can be much more severe.
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
A bottle may have varying depth ribs to achieve a balance of strength and rigidity while maintaining hoop strength. The varying depth ribs may smoothly transition around the circumference of the bottle from a flattened and/or shallow depth rib portion to a deep rib portion. A collection of flattened and/or shallow depth ribs act as recessed columns in the body of the bottle to resist bending, leaning, crumbling, and/or stretching. The deep rib portions provide hoop strength and make the bottle body more rigid and/or stiffer when gripped by a user. A balance may be achieved between of flattened and/or shallow depth ribs and deep ribs to attain a desired resistance to bending, leaning, and/or stretching while maintaining stiffness in a lightweight bottle.