The first step in developing the two-DOF orthotic knee joint prototype involved sketching potential designs in order to choose a realistic option for bracing the knee joint. The prototype was tested to determine its efficacy in more closely simulating the natural motion of the knee joint by assessing the limb-orthosis interaction force when the transverse plane DOF was locked versus when it was unlocked. 8, 9 As such, a prototype orth-otic knee joint was developed with two DOF in both the sagittal (i.e. To the best of the authors’ knowledge, no commercially available orthotic knee joint with more than one DOF is currently available. 8, 9 As such, the incorporation of an additional DOF in the transverse plane would allow the brace to more closely imitate the natural motion of the knee by allowing internal and external rotation. 7Ĭurrently available orthotic knee joints, including both single-axis or polycentric devices, have one degree of freedom (DOF) in the sagittal plane and therefore can only mimic the range of flexion and extension of the anatomic knee, thus restricting the joint’s natural movement.
#SOLIDWORKS 2005 ROTARY SIMULATION STOPS SKIN#
6 Furthermore, axial misalignment causes unnecessary reaction forces at skin and joint attachment points, resulting in discomfort and even outright injury. This mismatch can result in the pistoning of the brace components over the lower limb, constraining the wearer’s normal range of motion with the subsequent distal movement and potentially leading to misalignment of the brace and uncomfortable pressure on the skin. 4, 5 This is partly due to the structural design of these orthotic devices, which generally follow simpler kinematic pathways than those of the natural anatomic knee joint. 1– 3 Nevertheless, despite the positive effects of various types of knee braces, they limit the motion of the joint in all directions.
Knee braces are a conservative treatment option for patients with medial knee osteoarthritis (KOA). The problem is that we took some courses, about cercle de mohr and stress and strain, composite course, non-linear mechanics of structures. I think youre simply going this route to satisfy academic requirements Correct? This is a good example of why FEA still requires someone well aware of what theyre doing with mechanics and materials.Īnd to throw in a disclaimer, this method would never be used in practice to design deliverable parts to a customer.
Thats your only choice as its the most conservative and you have actual values for that material. I mean almost resin only strength with a higher modulus. Your tensile stregth is waaaaaayyyy too high.you cant use just fiber strength because its likely an order of magnitude greater than reality.Īgain, treat this as a linear isotropic but go with very conservative material properties if you cant find a close representation online or through testing. Also, the tables and curves tab is where you would put the non-linear data related to the stress strain curves and such. Well about the properties the problem is that i didn't find a source that give me those properties ! i found one but doesn't really help :Sītw in the properties manager of solidworks, when i put the type as non linear, i get only 4 options to enter ! which are : Poisson's ratio in XY, Thermal Expansion coefficient in X, Mass Density and Tensile strength in XĪs i use mostly ansys, im not sure why its not allowing more in solidworks.
#SOLIDWORKS 2005 ROTARY SIMULATION STOPS SIMULATOR#
This wont be taken to a race track correct?Īh i see, well this is a simulator cockpit where u sit it's just a simulator cockpit, now the second one i must do it a cockpit for an RC car which is 1/4 from the real one, let's say the real one is 1800mm in length, so mine should be 450mm in length The non linear is actually a less drastic approximation than isometric.especially if you have a lot of design margin. If you are approximating this to be isotropic, i would also approximate non linear. All of this data will be tabulated to detail the response at different strains, temperatures.etc. In FEA, especially non linear, you cant just use tensile strength, yield strength, modulus and density From one point. Clicking a button wont do too much wothout loading advanced properties. Sgth0mas wrote:Nonlinear elastic is technically correct, but it only benefits you if you load the material properties correctly to reflect the behavior over different strains.