Behavior of sandwich panels subjected to bending fatigue, axial compression loading and in-plane bending
Why this work is in the frame
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Bibliographic record
Abstract
This thesis investigates experimentally and analytically the structural performance of sandwich panels composed of glass fibre reinforced polymer (GFRP) skins and a soft polyurethane foam core, with or without thin GFRP ribs connecting skins.The study includes three main components:(a) out-of-plane bending fatigue, (b) axial compression loading, and (c) in-plane bending of sandwich beams.Fatigue studies included 28 specimens and looked into establishing service life (S-N) curves of sandwich panels without ribs, governed by soft core shear failure and also ribbed panels governed by failure at the rib-skin junction.Additionally, the study compared fatigue life curves of sandwich panels loaded under fully reversed bending conditions (R=-1) with panels cyclically loaded in one direction only (R=0) and established the stiffness degradation characteristics throughout their fatigue life.Mathematical models expressing fatigue life and stiffness degradation curves were calibrated and expanded forms for various loading ratios were developed.Approximate fatigue thresholds of 37% and 23% were determined for non-ribbed panels loaded at R=0 and -1, respectively.Digital imaging techniques showed significant shear contribution significantly (90%) to deflections if no ribs used.Axial loading work included 51 specimens and examined the behavior of panels of various lengths (slenderness ratios), skin thicknesses, and also panels of similar length with various rib configurations.Observed failure modes governing were global buckling, skin wrinkling or skin crushing.In-plane bending involved testing 18 sandwich beams of various shear span-to-depth ratios and skin thicknesses, which failed by skin wrinkling at the compression side.The analytical modeling components of axially loaded panels include; a simple design-oriented analytical failure model and a robust non-linear model capable of predicting the full load-displacement response of axially loaded slender sandwich panels, accounting for P-Delta effects, inherent out-of-straightness profile of any shape at initial conditions, and the excessive shear deformation of soft core and itsIn order to complete this study I need to express my gratitude towards my supervisor, Dr. Amir Fam.His guidance, leadership and support throughout
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it