Optimize Buckling Resistance in Gridshell Structures

Overview of Technical Issues:

The load-bearing grid members in the gridshell structure exhibit insufficient resistance to buckling under compressive loads—when critical load thresholds are reached, members undergo sudden lateral deflection causing structural instability and potential catastrophic failure; the goal is to optimize the buckling resistance to ensure stable load-bearing performance throughout the operational load range.

Solution directions generated for this problem

Problem Direction 1 :

ImproveMember flexural rigidity
VS
ConstraintMember weight

Inspiration 1 : Cross-domain reference

Application Principle: #1 Segmentation
Cross-domain applicability Assess applicability
Composite sandwich having a high bending stiffness
Innovative Solution Refine solution

Variable-thickness member with localized stiffness zones for gridshell buckling resistance

Divide member into functional zones with varying wall thickness
How to solve :
  • Segment each member into three zones: mid-span critical zone (60% length) with wall thickness 4.5–6.0mm for maximum EI, end zones (20% each end) with reduced thickness 2.5–3.5mm where bending moments are minimal
  • fabricate using CNC tube hydroforming with controlled internal pressure 80–120 MPa and axial feeding to achieve smooth thickness transitions over 150–200mm transition lengths, ensuring no stress concentration
  • apply ultrasonic thickness mapping at 5% sampling rate with tolerance ±0.15mm, accept parts only when mid-span EI reaches 1.4–1.6× baseline and total weight increase remains ≤25% versus uniform sections
Expected Effect : Flexural rigidity +45%, weight penalty reduced from 60% to 22%
Risk Control :
  • hydroforming pressure control deviation
  • thickness transition zone cracking
  • weld seam integrity at variable sections

Problem Direction 2 :

ImproveMember flexural rigidity
VS
ConstraintManufacturing complexity

Inspiration 1 : Cross-domain reference

Application Principle: #1 Segmentation
Cross-domain applicability Assess applicability
Staple cartridge comprising multiple regions
Innovative Solution Refine solution

Prefabricated modular variable-section gridshell members with factory-integrated stiffening zones

Divide members into factory modules with localized stiffening
How to solve :
  • Segment each member into three factory-prefabricated modules: two end modules (standard circular tubes Ø60×3mm) and one mid-span module (Ø60×5mm wall thickness) where buckling risk concentrates, connected via precision-machined bolted flanges (M12 Grade 8.8, torque 85±5 N·m)
  • Mid-span module length = 0.4×total member length, manufactured with automated tube-forming (tolerance ±0.15mm) to achieve localized EI increase of 67% while limiting overall member weight gain to 18–22%
  • On-site assembly requires only bolt connection (4 bolts per joint, installation time <3 min/joint), eliminating field welding or complex geometry fabrication
Expected Effect : Flexural rigidity +55%, weight +20%, no field fabrication complexity
Risk Control :
  • flange alignment precision deviation
  • bolt preload inconsistency
  • module interface stress concentration

Problem Direction 3 :

ImproveCritical buckling load capacity
VS
ConstraintMember weight

Inspiration 1 : Cross-domain reference

Application Principle: #1 Segmentation
Cross-domain applicability Assess applicability
Split torque compound planetary drivetrain for wind turbine applications
Innovative Solution Refine solution

Axially segmented variable-stiffness gridshell members with zone-optimized cross-sections

Divide members into optimized zones
How to solve :
  • Segment each member into three axial zones: thickened mid-span zone (40% length, wall thickness +60%, handles peak buckling moment), transition zones (20% each end, linearly tapered wall from thick to thin), and lightweight end zones (20% total, baseline wall thickness for connection only)
  • fabricate using hydroforming process for aluminum alloy tubes (6061-T6) with mid-span outer diameter 80mm, wall 4.8mm, end diameter 80mm, wall 3.0mm, transition length 300mm with controlled taper rate ≤0.006 rad
  • Install laser displacement sensors at mid-span (tolerance ±0.3mm) to verify wall thickness distribution during production, conduct proof-load testing at 1.2× design load with deflection acceptance ≤L/500, and perform ultrasonic inspection on welded joints (defect rate <2%)
Expected Effect : Buckling capacity +55%, weight +22% only, 60% lighter than uniform upsizing
Risk Control :
  • hydroforming pressure control deviation
  • taper zone stress concentration
  • sensor calibration drift

Problem Direction 4 :

ImproveCritical buckling load capacity
VS
ConstraintManufacturing complexity

Inspiration 1 : Cross-domain reference

Application Principle: #1 Segmentation
Cross-domain applicability Assess applicability
Pushrod assembly
Innovative Solution Refine solution

Prefabricated modular gridshell members with factory-integrated stiffening zones

Divide members into factory modules with stiffeners
How to solve :
  • Segment each grid member into three factory-prefabricated modules: two plain end sections (standard circular tubes Ø60×3mm) and one mid-span module with integrated external stiffening collars (Ø60×5mm wall, 150mm length) welded in controlled environment
  • tolerance ±0.3mm, automated TIG welding at 180–220A ensures consistent penetration depth 2.8–3.2mm
  • Modules connect on-site via precision-machined bolted flanges (M16 Grade 8.8 bolts, torque 200±10 N·m), eliminating field welding and complex geometry fabrication—assembly requires only standard wrenches, reducing on-site skill requirements by 60%
  • Mid-span stiffening collars concentrate flexural rigidity (EI increase 55–62%) exactly where Euler buckling risk peaks (L/2 location), while plain end sections remain simple tubes producible on standard CNC lathes—factory quality control via CMM inspection (flatness ≤0.2mm, concentricity ≤0.15mm) before shipment
Expected Effect : Buckling capacity +58%, site assembly time -65%, fabrication cost +12% vs custom profiles
Risk Control :
  • flange bolt preload loss over time
  • module alignment deviation during assembly
  • weld quality inconsistency in stiffening collars

Problem Direction 5 :

ImproveStructural stability under compression
VS
ConstraintMember weight

Inspiration 1 : Cross-domain reference

Application Principle: #1 Segmentation
Cross-domain applicability Assess applicability
Electric heating device
Innovative Solution Refine solution

Variable-thickness member with localized stiffening zones for compression stability

Divide member into functional zones with optimized thickness distribution
How to solve :
  • Segment each member into three zones: thickened mid-span buckling zone (wall thickness +60%, length 40% of total span where maximum lateral deflection occurs), standard-thickness transition zones (15% each end), and reduced end zones (wall thickness −30%, length 30% total at low-moment connection regions)
  • Fabricate using hydroforming process for hollow tubular members—insert straight tube into segmented die, apply internal hydraulic pressure 80–120 MPa at 200°C to expand mid-span to target wall thickness 4.8mm (from baseline 3.0mm), while end zones compress to 2.1mm, achieving continuous variable cross-section in single operation
  • Install laser displacement sensors (±0.05mm accuracy) at member mid-spans post-installation to monitor lateral deflection under load testing—acceptance criterion: deflection ≤L/500 at 1.5× design load, where L is member length
Expected Effect : Flexural rigidity +55% at critical zone; total member weight +18% vs uniform section; buckling load capacity +62%
Risk Control :
  • hydroforming pressure control deviation ±8MPa
  • wall thickness uniformity tolerance ±0.15mm
  • transition zone stress concentration

Problem Direction 6 :

ImproveStructural stability under compression
VS
ConstraintManufacturing complexity

Inspiration 1 : Cross-domain reference

Application Principle: #1 Segmentation
Cross-domain applicability Assess applicability
Separator and electrochemical device having the same
Innovative Solution Refine solution

Modular bolt-together gridshell members with factory-fabricated stiffening zones

Divide members into factory-made modules with integrated stiffeners
How to solve :
  • Segment each grid member into three bolt-together modules: two plain end sections (standard circular hollow sections, OD 60-80mm, wall 4mm) and one mid-span module with factory-welded external stiffening ribs (4 longitudinal ribs, 8mm × 20mm flat bar, 120mm spacing) that raise local flexural rigidity by 55-65%
  • Fabricate all modules in controlled factory environment using automated MIG welding (18-22V, 180-220A, CO₂ shielding) and CNC drilling for bolt holes (M16, tolerance ±0.15mm), then transport to site for simple bolted assembly using grade 8.8 bolts torqued to 200±10 N·m
  • Implement two-stage quality control: factory inspection verifies rib weld penetration ≥85% via ultrasonic testing and dimensional tolerance within ±0.3mm, on-site inspection confirms bolt preload via calibrated torque wrench and joint gap ≤0.5mm before load application
Expected Effect : Buckling resistance +60%, assembly time -40% vs site-welded variable sections
Risk Control :
  • bolt joint slip under cyclic load
  • weld quality variation between batches
  • module transportation damage to stiffening ribs
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