I would like to know what are the differences between the reaction forces and the external forces that Solidworks calculates after a static study.
Let me explain: I have a steel plate with 4 bolt-type anchors on a virtual wall.
The parameters of my anchors were entered correctly (diameter of the bolt, the rod, resistance section,.......). So far no worries. I do my static study and check the axles/bolts, my 4 anchors are green, that is to say that the pre-sizing of the latter is correct.
My problem is to know if the concrete will resist (i.e. the virtual wall), i.e. the tearing off of my anchors, (the anchor slides into the concrete holes), or if the anchor does not slip, but tears the concrete by cone effect.
I don't know if I have to look at the reaction forces or the external forces, to have the stress that the concrete receives through the anchors.
Your help will be welcome, to enlighten me on this subject.
The simulation is not designed to measure the stress resistance of concrete.
What for? 1°) The wall is VIRTUAL , which means that it does not exist or, more precisely, is considered to be infinitely undeformable. 2°) The simulation with the bolt connectors are done to see how the plates behave (deformation, resistance) in no case does it care about the concrete and even less about the studs.
3°) the pins or dowels that will be inserted into the concrete correspond to precise standards always specified by the supplier (SPIT, HILTI, etc.) 4°) only the concrete engineer can give the specifications (if it is an old slab or no documented specifications on the concrete used it complicates because you have to do a survey or a tear test) so that your suppliers of dents, struck dowels, screwed or chemical dowels validate your choice.
Generally speaking, anchors are oversized, four bolts per foot when two would be enough, for example. You need to know where your responsibility lies, whether on the building or on the concrete anchoring as well. Only points two and three must be safe, otherwise your responsibility is only for the building according to the constraints of the Specifications.
Sorry for the late reply, and thank you for your answer.
I understand that a virtual wall is not a concrete wall and is therefore considered infinitely rigid.
I probably expressed myself badly:
During a simulation, when we add anchor bolts in Solidworks, (with all the parameters dedicated to the bolts), the latter tells us if the bolt is suitable or not, (green or red color), depending on the characteristics we have entered. This is the intrinsic ability of bolts.
I also understand that there are anchor bolt calculation software such as hilty, Spit, Wurth,.....,
My question is the following: can we use the external forces that SolidWorks gives, (for example in the center of my frame, with my 4 anchor bolts), to determine, on the dedicated software, the behavior and the holding of these bolts?
Second question: What are reaction forces in Solidworks?
Your question: (can we use the external forces that SolidWorks gives, (for example in the center of my turntable, with my 4 anchor bolts), to determine, on the dedicated software, the behavior and the holding of these bolts?)
Yes, but under conditions! Yes, if the upward pull conditions are strictly vertical. You can check in part according to your simulation assumptions and whether the forces exerted on the bolts are approximately equal. Be careful if your forces are not strictly vertical (e.g. in the case of a column subjected to the wind or subjected to pressure or lateral forces leading to buckling)
The forces of reaction are those classic of literature, for a long time Archimedes started in his bath but HERE it is above all Newton's second law, also called Principles of Reciprocal Actions" I often give a simple explanation: it is the counterforce opposed to a force. If you lift a weight statically, the force and counter-force (reaction force) are equivalent.
If your pulling force is greater than the holding counterforce, then you have a pull-off. Tearing is where concrete comes in ;-)
You asked the same question in your post of June 14, 2020 (which you can close by designating an answer). For Solidworks, this makes sense if you are doing a simulation on a subassembly that will later be fixed in another ASM. If you know the reaction force from the simulation of a subassembly, it allows you to know the force to be applied to the other subassembly or to the ASM without simulating both simultaneously. This allows the other designer (other supplier) or you to make a simulation for each subset independently of each other.
Thank you for this answer which sheds a little more light on the results of simulations.
If I understand correctly, we can use the external forces that the turntable undergoes to calculate whether or not the anchors are good.
Tell me, if I'm wrong. See images.
For you say afterwards:
"If your pulling force is greater than the counterforce (force opposed to force) of holding then you have a pull-off. Tearing is where concrete comes in ;-)"
I don't understand this sentence because it contradicts your first paragraph?
so SW must be able to give the reaction forces in relation to the plate or the virtual wall (concrete wall).
Except that here, I have a problem, SW doesn't give me any values when I select the reaction forces. I admit I get stuck, or even dry......
I don't think I'm contradicting myself, but poorly explained maybe ;-) or I'm a loser
Suppose that the 4 SPIT pegs resist 86,777 N according to Z (Nz according to SPIT) in tension perfectly oriented parallel to the ground. And if your frame exerts a vertical traction according to Z and strictly parallel to the ground of 55 OOO N, then no tearing. This means that the counter-force (concrete) is in this case greater than the pull-out force of the frame. In other words, if you exert a force with your frame greater than 86,777 N, it's either the pegs that fart or the concrete cone that goes on vacation to the Parthenon.
For the results, don't put them in scientific notation, it's easier to compare to SPIT which is in direct reading. I don't see the XYZ repository in the partial view from SW. I guess the blue arrow is along the Z-axis. This would give for SW FRes = 8.69 x 10+4 or 8.6900 and for SPIT 8.6777 x 10+4
This shows that the figures you give for the SPIT simulator do not take into account a CS since the two values are almost identical, the SPIT and the concrete must take into account the CS either . In other words, the concrete and the dowels must be stronger than SW FRes = 8.69 x 10+4
For the record (Source SW - If you select a datum axis, the moment of the reaction forces is calculated only with respect to that axis. The moment arm is the distance between the constrained nodes on which the reaction forces are calculated from the axis. ...: Converts the three force vectors (X, Y, and Z components) into the resultant force vector. Only the resultant force vector is displayed. )
I don't know how to put the results in floating mode.
In order for SW to give the reaction forces, an imposed displacement of the plane support type, which corresponds to the virtual wall, must be added.
What I understand by:
- The virtual wall is there for the intrinsic sizing of the anchor bolts (tensile steel break: acial force; Shear plane failure, or torque failure)
- the imposed displacement of the plane support type makes it possible to know the reaction forces of the entire plate or of the holes in the plate for anchor bolts.
The only downside, in relation to what SW's help says: to know the forces and reaction moments of a solid: you must:
a coordinate system.
I deduce from this but I'm not at all sure that, to calculate the anchor bolts on Spit, it takes 3 reaction forces and 3 moments given by SW and not the external forces?, I'm lost.
By creating a coordinate system as shown, I can't find my 3 forces and 3 moments to put in the SPIT software, in order to calculate the anchor bolts, at best I have a force if I choose the frame, or 4 forces if I select my 4 holes for the bolts.
View image
Moreover, the addition of the 4 forces does not give me the resultant on the turntable.
Well let's relax;-) Theory is good but let's stay pragmatic ;-) ;-)
It's normal that the addition of the 4 forces doesn't give me the resultant on the board because it's a calculation on the mesh of the whole board, each node has its own value according to the distribution of forces on each node and each DLL.
Let's get back to our onions and the shepherds who keep them! Your results with coordinate systems are very interesting because it shows the overall reaction force which is more or less the average of the reaction forces of the four holes in the stage.
If I were in your place, I would take the test without the coordinate system which does not bring anything more in this case.
What we notice is that there are small differences between the four FRes, the largest being the one at 1.74 x 10+4 .
So you just have to add to the "1.74 x 10+4" one safety coeff of 1.5 or 2 or more depending on whether it is a static charge or not. (Coeff 10 for an elevator)
You can know the CS value of your design, or else you risk oversizing your bolts. By the way, what is the CS of your design?
Once you have the value with the safety coefficient, you pass it in the SPIT simulator and you will know the correct diameter of the SPIT bolts and you will also know if the diameter of your holes holds up or not.
The results that are given are calculated with a load at the ULE, i.e. 1.35G+1.5Q, I have a CS of 1.4 on the whole model.
For the simulation with the Spit software I can only give the loads in the center of the plate, so I have to take the value of SW in the center of the plate? Or how can I bring each reaction value of the holes back to the center of the hole?
