Effective Material Stiffness in Curved Actuators
Bibliographic record
Abstract
This study presents a new method for measuring the effective stiffness of curved actuators. Actuators are loaded into tension, and analytical mechanical equilibrium formulations are used to determine the stress along the actuator. A new mechanical metric, Shape Actuation Modulus (SAM), defines the effective stiffness of the actuator during loading as the ratio of stress change to radius of curvature change. Conductive polylactic‐acid shape‐memory actuators are produced to benchmark this novel methodology. These actuators display a linear behavior between 25 and 50 mm radius of curvature with SAM of 3.8±0.9 MPa at 50 mm. The interval on which the radius of curvature to stress relationship is linear can be controlled by choosing the radius of curvature of the hinge. For instance, SAM calculation with R 2 > 0.97 was achieved in ranges of [22.7;79.6] mm and [16.4;51.5]mm for starting radius of curvature of 23.5±0.7 mm and 17.2±0.6 mm, respectively. Hence, the new technique proposed provides guidelines to design actuators. Finally, a comparison of bio‐composite actuators made of the same material was conducted. The hygromnemic actuators tested displayed a stiffness more than one order of magnitude larger than the hygromorphic ones for the range of radius of curvature [20;100]mm.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".