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# What is static Determinacy?

## What is static Determinacy?

A statically determinate structure is one that is stable and all unknown reactive forces can be determined from the equations of equilibrium alone. A statically indeterminate structure is one that is stable but contains more unknown forces than available equations of equilibrium.

## How do you calculate static Determinacy?

A truss is considered statically determinate if all of its support reactions and member forces can be calculated using only the equations of static equilibrium. For a planar truss to be statically determinate, the number of members plus the number of support reactions must not exceed the number of joints times 2.

How do you calculate Determinacy?

Internal Determinacy: ie=(3m+r)−(3j+ec) m=2,r=4,j=3,ec=1 (Again, the hinge on the left at the pin does not provide any additional equations of condition). Therefore, 3m+r=10, 3j+ec=10, and ie=0.

How do you determine if a frame is stable or unstable?

structure is stable. o If removal of one constraint (a support force or a member force) causes the structure to be unstable (i.e. the structure can be displaced without deforming a member), then the original structure is stable and determinate.

### What is static and kinematic Determinacy?

28. Static Indeterminacy Internal Indeterminacy : If no. Kinematic Indeterminacy • Kinematic Indeterminacy = Degree of Freedom • If the displacement component of joint can’t be determined by Compatibility Equation , it is called Kinematic Indeterminant Structure.

### What is the degree of Determinacy?

A fixed beam is kinematically determinate and a simply supported beam is kinematically indeterminate. (i) Each joint of plane pin jointed frame has 2 degree of freedom. (ii) Each joint of space pin jointed frame has 3 degree of freedom. (iii) Each joint of plane rigid jointed frame has 3 degree of freedom.

What shape is a truss?

Triangles
Triangles can be used to make trusses. Trusses are used in many structures, such as roofs, bridges, and buildings. Trusses combine horizontal beams and diagonal beams to form triangles.

How do you know if a structure is stable?

A structure is considered stable if it maintains its geometrical shape when subjected to external forces. r = number of support reactions. C = equations of condition (two equations for one internal roller and one equation for each internal pin).

## How do I know if my truss is stable?

structure is unstable. If the displaced shape cannot be drawn without causing a member to deform, the structure is stable. unstable (i.e. the structure can be displaced without deforming a member), then the original structure is stable and determinate (see Figure 2 for an example).

rigid truss
A rigid truss will not collapse under the application of a load. A simple truss is constructed by successively adding two members and one connection to the basic triangular truss.

When does a system have an external determinacy?

A system is externally statically determinate, if the number of support reactions is equal to the number of possible move- ment directions (equilibrium conditions).

What are the formulas for solving statics problems?

In many statics problems, you must be able to quickly and efficiently create vectors in the Cartesian plane. Luckily, you can accomplish your Cartesian vector creations easily with the handy vector formulas in this list: Force vectors and distance vectors are the most basic vectors that you deal with.

### How are shear and moment diagrams used in statics?

Shear and moment diagrams are a statics tool that engineers create to determine the internal shear force and moments at all locations within an object. Start by locating the critical points and then sketching the shear diagram. Points of zero shear (V = 0) — for moment diagrams only.

### Is the change in shear positive or negative in statics?

If the load area is positive, the change in shear is positive. If the shear area is positive, the change in moment is positive. In many statics problems, you must be able to quickly and efficiently create vectors in the Cartesian plane. Luckily, you can accomplish your Cartesian vector creations easily with the handy vector formulas in this list: