Universal Strain‐Life Curve Exponents for Thermoplastics and Elastomers under Tension‐Tension and Torsion
Bibliographic record
Abstract
Abstract The fatigue behavior of 28 amorphous and semi‐crystalline thermoplastic polymers and elastomers is tested under strain controlled sinusoidal tension‐tension (TT) and torsion (T) at room temperature and analyzed via strain‐life (total strain amplitude versus fatigue lifetime) and crack propagation rate versus total strain amplitude curves, analogous to Paris’ law. Investigating fatigue is extremely time‐ and resources consuming, so universal relationships between the exponents of the strain‐life power‐law and material properties are of high importance. For a brittle failure mechanism (I), the strain‐life curves are found to have fixed exponents of B TT,I = −0.27 and B T,I = −0.22, respectively, while the crack propagation versus strain amplitude in TT has an exponent of m da/dN,I = 4. For ductile failure (II), fixed strain‐life curve exponents in TT of B TT,II = −0.35 and in torsion of B T,II = −0.48 with m da/dN,II = 2.8 are obtained. In torsion, most semi‐crystalline polymers show brittle and ductile failure depending on the applied strain amplitude, so the strain‐life curve exponent changes accordingly. The universal exponents for strain‐life and crack growth‐strain amplitude curves offer a significant simplification to rapidly estimate, predict, and simulate the fatigue behavior of polymers.
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How this classification was reachedexpand
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) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| 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 itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".