Mohr's Circle, step by step
Plane stress. Angles on the circle are twice the angles on the element.
- Plot the two face pointsPlot (σx, τxy) and (σy, minus τxy) on normal and shear axes.
- Join themThe line crosses the normal-stress axis at the centre of the circle.
- Read the centreCentre = (σx + σy) ÷ 2. Rotation never moves it.
- Read the radiusR = √(half the stress difference squared, plus τxy squared).
- Take off the answersPrincipal stresses are centre ± R; maximum shear is R itself.
The sum of the two normal stresses is invariant under rotation. That is the check on your centre.
Questions about the Mohr's Circle poster
- What’s on the Mohr's Circle poster?
- 5 numbered steps. Plane stress. Angles on the circle are twice the angles on the element. Plot the two face points — Plot (σx, τxy) and (σy, minus τxy) on normal and shear axes.; Join them — The line crosses the normal-stress axis at the centre of the circle.; Read the centre — Centre = (σx + σy) ÷ 2. Rotation never moves it.; Read the radius — R = √(half the stress difference squared, plus τxy squared).; Take off the answers — Principal stresses are centre ± R; maximum shear is R itself.. The sum of the two normal stresses is invariant under rotation. That is the check on your centre.
- Who is the Mohr's Circle poster for?
- Mohr's Circle belongs to the Mechanical Engineering section rather than to a school year, because engineering is not something one grade owns. Anyone learning mechanics of materials can pin it up — a beginner, a student mid-course, or someone revising years later.
- When should you use the Mohr's Circle poster?
- Any time two stresses and a shear act together and you need the worst case. A wall chart earns its place by being glanceable from where the work is happening, so Mohr's Circle belongs on the wall where that engineering work actually happens, within glancing distance, rather than filed away.
- What other posters go with Mohr's Circle?
- Axial Stress & Strain, Beam Bending Stress and Beam Deflection Cases sit alongside Mohr's Circle in the Mechanical Engineering section. Printed together they make a wall rather than a single sheet, which is how a reference set actually gets used.Axial Stress & StrainBeam Bending StressBeam Deflection Cases
- Is the Mohr's Circle poster free to download and print?
- Yes. Mohr's Circle downloads as a free PDF with no account, no email and no watermark, like everything else in the Mechanical Engineering section. Print as many copies as you like for a home, a classroom, a library or a tutoring group; reselling the file is the only thing the licence rules out.Read the licence
- What size does the Mohr's Circle poster print at?
- Mohr's Circle is a vector PDF laid out for US Letter, and prints on A4 with Fit to page — the same file, no separate download. Because every mark on it is drawn rather than photographed, it stays sharp enlarged to A3, A2 or A1 at a copy shop. Colour carries emphasis only, so a greyscale print of Mohr's Circle loses nothing.Printing guide
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