Case 1319 ยท Public preview
A Small Edge Notch Can Control Fracture of a Brittle Resistor Substrate
A resistor measured open, displayed a visible transverse crack, and separated completely when removed from the assembly.
SEM fractographyBackscattered-electron imagingMulti-angle fracture examinationEDSCrack-path analysis
What the evidence preview establishes
The resistor fractured from a small notch in the bottom edge of its alumina substrate. Repeated low-level bending, most likely during vibration, propagated the crack until the thick-film resistor opened.
Why this case matters
A brittle-component crack should be traced to its precise edge origin before being labeled simple overload. A small manufacturing notch can raise local stress enough for repeated board bending to grow a crack under loads that an undamaged substrate would tolerate.
Full evidence reserved for MEMBER and STOREThe complete case includes the evidence sequence, four interpreted figures, alternative explanations, limitations, and practical application guidance.