Interview Tech Tip!! Wondering what technical questions will be asked in a mechanical engineering interview?
The one technical topic that gets asked more than any other is the stress-strain curve. The depth with which interviewers go can often vary, however, the starting place is almost always a question asking you to describe the stress-strain curve for a ductile material. The graphic shows the most fundamental details to first note, which include the axes (stress and strain), regions, and the core three curve points. The first is yield strength, which defines that max stress present in the elastic region of the curve. This point is significant because up until here, stress and strain are linearly related, and a release of the induced stress results in the material behaving “spring-like” and returning to its original form. Any increase of stress from here begins plastic, or unrecoverable, deformation for which stress and strain continue to both rise until the peak ultimate strength is met of the material. This defines the max tensile strength, or highest load, that a material can handle before failure. After this point, necking (or localized thinning) of the material begins as the material continues to strain under tensile load until the facture point and the material fails.
The general plot, these three key points, and elastic and plastic regions are the foundational details you must know. If these are all basic details for you, stick around for future content on other critical details of this graph including Young’s Modulus, strain hardening, true stress strain curve, Modulus of Toughness, Modulus of Resilience, and oh so much more!
