Crane Jib Load Curve Optimization via Element Stress Simulation
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Solution Overview
Problem
Current methods for defining load curves for cranes limit the use of jibs by considering only the maximum load at the largest reach, leading to excessive restrictions on usage at other reaches.
Innovation Solution
A method that simulates a crane's jib structure to calculate stresses at various reaches, incrementing or decrementing theoretical loads until maximum stresses are achieved, allowing for an optimized load curve that utilizes the crane's capacity at each reach, and includes a monitoring system to prevent overloading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a load curve is defined based on maximum load at the largest reach, then the structural boundary is determined, but the use of the jib is excessively limited at other reaches
Solution Approach 1:
The patent divides the jib structure into multiple discrete elements (first element, second element, third element, etc.) and analyzes the stress in each element separately. This segmentation allows the load curve to be optimized for each structural component individually, enabling the jib to operate at maximum capacity across all reaches rather than being limited by the single most critical element at maximum reach.
Solution Approach 2:
The patent applies different maximum stress criteria to different elements of the jib structure based on their specific structural characteristics and stress patterns. Each element is evaluated with its own predetermined maximum stress threshold, allowing the load curve to reflect the actual local capacity of each structural component rather than applying a uniform limitation across the entire structure.
2Stability of the object's composition
If the load curve limits usage to maintain constant maximum load moment, then structural safety is ensured, but operational flexibility is reduced
Solution Approach 1:
The patent transitions from a static load curve definition (constant maximum load moment) to a dynamic definition where the maximum theoretical load varies with reach based on actual structural capacity. By evaluating stress in each element at each reach and determining the maximum load accordingly, the load curve becomes adaptive to the specific structural conditions at each operating point, enabling flexible operation while maintaining safety.
Solution Approach 2:
The patent changes the parameters used to define the load curve from a single constant maximum load moment to multiple reach-specific maximum theoretical loads. Each load value is determined by the actual stress conditions and structural capacity at that specific reach, allowing the operational parameters to be optimized for each working condition rather than constrained by a conservative constant limit.
Data Source
AI summary
This defining method comprises the steps of: —simulating a crane comprising: i) a boom made up of elements and ii) a lifting member that is able to move along the boom, —selecting several elements to be tested, maximum stresses, and several ranges along the boom, and —carrying out the following analysis steps of: •choosing a theoretical load, •calculating stresses brought about by the theoretical load in each element to be tested, •comparing these stresses with maximum stresses, •increasing or decreasing the theoretical load depending on whether stresses are less than or greater than the maximum stresses, •repeating the calculating step and the comparison step and the step of increasing or decreasing until the maximum theoretical load is found, and •recording i) the range and ii) the maximum theoretical load.