1 thought on “Shear Force and Bending Moment diagrams without Sign Conventions”
Lena
Thank you for your work, and I hope it will help some students understand the visualisations using the ‘buigteken’ en ‘dwarskrachtteken’. Allow me to disagree though when you state that the usual sign conventions cause confusion. Not if you learn them properly! With my German background and training, i used to place a dotted lign on one side of the beam. By doing that, I chose the side i consider to be the underside of the beam. You can also visualise it as by placing a cord under the beam. A positive moment is the moment that elongates that cord, puts it in tension. This is therefore the positive bending moment (and the smiley buigteken). I agree that in the Dutch way the shear force is better visualised with the sign, you can easily imagine which way it goes once you get used to it. With my way (the German way), after defining the dotted line, you also need to define a direction (left to right/top to bottom or opposite) in order to be clear about the positive corresponding shear force definitions. Feel free to contact me, with some sketches I can visualise the point i am trying to make. Whichever way you use however, i think what matters most is to understand what the actual directions/reactions are, know where tension/compression is in the beam. I’m sure your books and materials can help to get this understanding, so thank you for that.
Thank you for your work, and I hope it will help some students understand the visualisations using the ‘buigteken’ en ‘dwarskrachtteken’. Allow me to disagree though when you state that the usual sign conventions cause confusion. Not if you learn them properly! With my German background and training, i used to place a dotted lign on one side of the beam. By doing that, I chose the side i consider to be the underside of the beam. You can also visualise it as by placing a cord under the beam. A positive moment is the moment that elongates that cord, puts it in tension. This is therefore the positive bending moment (and the smiley buigteken). I agree that in the Dutch way the shear force is better visualised with the sign, you can easily imagine which way it goes once you get used to it. With my way (the German way), after defining the dotted line, you also need to define a direction (left to right/top to bottom or opposite) in order to be clear about the positive corresponding shear force definitions. Feel free to contact me, with some sketches I can visualise the point i am trying to make. Whichever way you use however, i think what matters most is to understand what the actual directions/reactions are, know where tension/compression is in the beam. I’m sure your books and materials can help to get this understanding, so thank you for that.