Container Lashing Element for Compressive and Tensile Load Control
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Solution Overview
Problem
Current container securing systems on large ships are inadequate for withstanding extreme loads during parametric rolling, leading to container stack failures and accidents, as they primarily function as tensile systems that concentrate loads on one corner fitting, failing to absorb compressive forces effectively.
Innovation Solution
A lashing system that provides a pressure-resistant and tension-resistant connection between lashing elements and container corner fittings, using turnbuckles for length adjustment and ball elements for secure, directional connections to distribute loads and absorb both tensile and compressive forces, thereby stabilizing the container stacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional tensile lashing systems are used to secure container stacks, then the containers can be locked together with twistlocks at corner fittings, but the systems fail to withstand extreme compressive loads during parametric rolling, leading to stack collapse
Solution Approach 1:
The lashing system is segmented into multiple independent lashing elements distributed around the container stack (typically 8-12 elements at different heights and positions). Each lashing element independently absorbs forces, and the distributed arrangement ensures that no single point bears excessive load during parametric rolling, preventing catastrophic stack collapse
Solution Approach 2:
The lashing elements are arranged in a three-dimensional configuration around the container stack, with elements positioned at multiple heights, radial positions, and angular orientations. This spatial distribution transforms the securing system from a simple tensile arrangement to a multi-dimensional force-absorbing structure that effectively resists complex parametric rolling loads from all directions
2Ease of operation
If lashing elements are arranged to engage corner fittings, then containers can be secured crosswise, but the loads concentrate on one corner fitting causing failure under extreme transverse loads
Solution Approach 1:
The securing system is divided into multiple lashing elements, each engaging different corner fittings of the container stack. This segmentation distributes the total load across multiple corner fittings rather than concentrating it on one, preventing local overload and failure while maintaining ease of operation through standardized engagement points
Solution Approach 2:
The lashing elements are strategically positioned at asymmetric locations around the container stack, with varying heights, radial distances, and angular orientations. This asymmetric arrangement optimizes load distribution by placing lashing elements where they most effectively counteract parametric rolling forces, rather than using a simple symmetric pattern
3Productivity
If multi-level lashing bridges are used to secure up to 12 layers of containers, then maximum stowage capacity is achieved, but the container stacks become vulnerable to tipping under extreme rolling movements
Solution Approach 1:
The lashing system uses multiple lashing elements distributed at different heights to secure each container layer independently. This segmentation allows the system to maintain stability for tall stacks (up to 12 layers) by preventing tipping at any level, while still achieving maximum stowage capacity through efficient use of vertical space
Solution Approach 2:
The lashing elements are arranged in a three-dimensional pattern around the container stack, with elements at various heights, radial positions, and angular orientations. This multi-dimensional arrangement creates a stable geometric structure that resists tipping moments from parametric rolling, enabling safe stowage of high container stacks without compromising stability
4Device complexity
If conventional lashing rods with hooks are used to engage corner fittings, then containers can be secured with simple connecting means, but the connection fails under extreme tensile and compressive forces
Solution Approach 1:
The lashing elements incorporate spherical or curved connection interfaces (such as spherical bearings, ball joints, or curved engagement surfaces) at the corner fittings. These curved surfaces distribute contact forces over a larger area and accommodate angular misalignments during parametric rolling, significantly increasing connection strength while maintaining relatively simple device complexity
Solution Approach 2:
The lashing elements use intermediary components (such as spherical bearings, bushings, or intermediate connection pieces) between the lashing rod and the corner fitting engagement. These intermediaries absorb and distribute extreme tensile and compressive forces, protecting the primary connection points from failure while keeping the overall connection mechanism relatively simple
Data Source
AI summary
The invention relates to a lashing element (10) for vertically connecting a container (100) or a stack (110) of at least two containers (100) arranged one above the other to a stop (40) on a surface, in particular on board a ship, with at least one element (24) for producing a releasable movable connection to the stop (40), with at least one element (18) for producing a detachable connection with a corner fitting (120) of the container (100), with at least one element (12) for changing a length of the lashing element (10) for adapting the length of the lashing element (10) and for tensioning the lashing element between the container corner (120) and the stop (40). It is provided that there is a pressure-resistant and tension-resistant connection between the at least one element (24) for producing a releasable movable connection with the stop (40) and the at least one element (18) for producing a releasable connection with a corner fitting (120) of the container (100).