beam simulation issues

Hi

im trying to practice  simulation static study using beam elements.

first, suppose i want to put a fixture at some intermediate point of a continuous beam as illustrated in figure 1 - how would i do it?.

I know it can be done by spliting the beam into two bodies ( and by doing so, creating  an additional node), but that  doesn't seems to me to be the correct method ( the beam will be drawn as two parts in the model drawing, which is not what i want).

the second issue- while doing trials with the model i found that the "immovable fixture" as defined by SW is probably not what i used to know from  statics.

as can be seen  (figure 2), the model which has an immovable fixtue at one end of the beam and force acting on the other side, has a simulation solution and is not found to be unstable as i would expect.

(i think of the immovable fixture as a  3d pin connection )

may somebody help  me with these questions.

thanks,

Zvi

SolidworksSimulation