Semicircular bend testing with split Hopkinson pressure bar for measuring dynamic tensile strength of brittle solids
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Bibliographic record
Abstract
We propose and validate an indirect tensile testing method to measure the dynamic tensile strength of rocks and other brittle solids: semicircular bend (SCB) testing with a modified split Hopkinson pressure bar (SHPB) system. A strain gauge is mounted near the failure spot on the specimen to determine the rupture time. The momentum trap technique is utilized to ensure single pulse loading for postmortem examination. Tests without and with pulse shaping are conducted on rock specimens. The evolution of tensile stress at the failure spot is determined via dynamic and quasistatic finite element analyses with the dynamic loads measured from SHPB as inputs. Given properly shaped incident pulse, far-field dynamic force balance is achieved and the peak of the loading matches in time with the rupture onset of the specimen. In addition, the dynamic tensile stress history at the failure spot obtained from the full dynamic finite element analysis agrees with the quasistatic analysis. The opposite occurs for the test without pulse shaping. These results demonstrate that when the far-field dynamic force balance is satisfied, the inertial effects associated with stress wave loading are minimized and thus one can apply the simple quasistatic analysis to obtain the tensile strength in the SCB-SHPB testing. This method provides a useful and cost effective way to measure indirectly the dynamic tensile strength of rocks and other brittle materials.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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 |
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