Fatigue damage and life assessment of welded joints based on energy methods
Notice bibliographique
Résumé
The present study intends to evaluate fatigue damage of different welded joints under loading conditions and their response on fatigue lifetime. The main variables influencing the fatigue life of a welded joint are: applied stress amplitude, material properties, geometrical stress concentration effects, and size and location of welding defects. In order to carry out the study, calculations have been performed using the parameters in three energy-based models. Calculations have been carried out separately for each model from the original experimental data obtained from available literature related to each welded joint. The data variables used as a basis for the calculations of the energy-based models for different welded joints include: cyclic stress-strain properties related to the base metal material type of the welded joints, dimensional and geometrical information on the welded joints, and stress versus endurance cycle tables obtained from the tests performed on the welded joints. All the mentioned variables are parameters influencing the fatigue life of a welded joint. Fatigue damage assessments were performed and discussed based on earlier developed energy damage approaches consisting of: (i) the hysteresis loop based parameter of Masing type material, (ii) the notch stress-intensity based parameter and (iii) the critical plane/energy based parameter. In evaluating fatigue damage of welded joints, these approaches were discussed based on the comparison of energy-lifetime diagrams obtained from each energy model and how readily coefficients/constants are determined and employed in the parameters. In addition, a finite element analysis was performed on selected welded joints to obtain local peak stress values and their location. Numerically obtained stress concentration factor and fatigue notch factor values were also compared with their analytical values. To assess fatigue damage of welded joints based on various energy models, different sets of experimentally obtained fatigue data performed by different laboratories under uniaxial loading conditions available in literature were chosen. The welded joints used in this study were butt joint, cruciform joint, butt-ground joint, and butt-strap fillet joint. The welded joint base metals included low carbon structural steel, aluminium alloys, and carbon steel. The energy models were compared for their energy-fatigue life curve slopes and their ability to converge the related nominal stress-life scatter. The energy values calculated based on their models included the effect of variables of cyclic stresses. Important results were concluded for welded joints from the study including: the relation between fatigue notch factor and fatigue strength, the stress-life diagram slope and fatigue resistance, the ability of the energy models to reflect the fatigue notch factor, and merits and disadvantages of each energy model.
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,001 |
| Bibliométrie | 0,003 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,001 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,001 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».