RepOD

This data repository supports a series of articles focusing on the study and analysis of imperfections in thin-walled, cold-formed steel sections with modified cross-sectional shapes. Using 3D scanning techniques, the research identifies the most vulnerable geometric imperfections in these profiles. The repository includes detailed data from the scans, which highlight the geometric imperfections that significantly impact the resistance to stability loss in thin-walled structures.

The primary objective of the research is to analyze the actual shape inaccuracies and their influence on the stability and ultimate load-bearing capacity of bent thin-walled beams and compressed columns with non-standard C-shaped cross-sections. The secondary objective is to evaluate the usefulness of optical methods in the experimental analysis of thin-walled beams and to compare these methods with other research techniques.

The collected data encompasses:

• Coordinate scanning reports of beams with various cross-sectional shapes (B0, B1, B7, B9, B15).
• Comparison figures of actual versus ideal beam cross-sections.
• Technical drawings and dimensioned illustrations of the B7 beam cross-section.
• Charts showing fluctuations and deviations in geometric imperfections and angular dimensions along the length of the beams.
• Graphics depicting stress and deflection in bent beams, both with and without imperfections.
• 3D model files in STP format of the beams with B0, B7, and B14 cross-sections derived from 3D scanning.
• Finite Element Analysis (FEA) models prepared for B7 cross-section beams, including both actual and ideal configurations, in standard and shorter lengths.

Methodology

The research process in this OPUS project involves several stages:

1. 3D Scanning of Beams:

• Actual beams produced by subcontractors are scanned using optical measurement systems such as OPTOCAD, Atos, and Aramis.
• The 3D scanning results, including the point cloud and polygonal triangular model, are converted into surface CAD models.
• These CAD models determine the actual dimensions and geometric properties of the cross-sections, which may vary along the beams.

1. Experimental Testing:

• The actual beams are tested using a Zwick Z100 tensile strength machine under two load cases: 4-point bending and axial compression.
• Strains at selected points are measured using strain gauges, and beam deflections are measured with a deflection sensor.
• Critical and limit loads are determined.
• Specimens prepared from spare material are tested to determine the exact material properties and a stress-strain curve for numerical models.

1. Numerical Simulations:

• Numerical simulations based on Finite Element Method (FEM) and CuFSM are conducted on both the actual (scanned) beams and their theoretical counterparts under pure bending and compression.
• Ansys, SolidWorks Simulation Premium, and CuFSM software are used to compare results.
• The stress-strain curve obtained from experimental testing is applied in these simulations to accurately model the actual material.

1. Comparison and Analysis:

• Results from experimental investigations are compared with numerical simulation outcomes.
• Qualitative and quantitative analyses are performed.
• The influence of geometric imperfections on beam performance is evaluated to determine their criticality and identify the most vulnerable cross-sections.

This comprehensive methodology supports the objectives of analyzing shape inaccuracies and their effects on the stability and load-bearing capacity of thin-walled beams and columns with non-standard C-shaped cross-sections. Additionally, it evaluates the usefulness of optical methods in experimental analysis and compares them with other research techniques.