Which truss structure is more stable

It is recommended to have a triangle because it has stability.

The wooden bridge is not a truss, but a supporting beam, which is safe and easy to realize.

Triangular truss Under the nodal load evenly distributed along the span, the axial force of the upper and lower chords is maximum at the endpoint and gradually decreases towards the middle of the span. The axial force of the web member is reversed. Due to the large difference in the internal force of the chord, the material consumption of the triangular truss is not reasonable enough, and it is mostly used in the roof truss of the tile roof.

Trapezoidal trusses. Compared to triangular trusses, the stress on the members is improved and the process requirements of some industrial plants can be more easily met when used in roof trusses. If the upper and lower chords of the trapezoidal truss are parallel, it is a parallel chord truss, and the stress of the members is slightly worse than that of the trapezoid, but the type of web member is greatly reduced, and it is mostly used in bridges and trestles.

Polygon trusses.

Also known as polygonal trusses. The upper chord node is located on the secondary parabola, and if the upper chord is arched, the bending moment generated by the internode load can be reduced, but the fabrication is more complicated. Under the action of uniform load, the shape of the truss is similar to the bending moment pattern of the simply supported beam, so the axial force of the upper and lower chords is evenly distributed, the axial force of the web member is small, and the material is the most economical, which is a kind of truss form commonly used in the project.

Hollow truss The shape of the polygonal truss is basically adopted, and the upper chord nodes are straight lines, without oblique web members, and are only connected by vertical web members and upper and lower chords. The axial force distribution of the members is similar to that of the polygonal truss, but the bending moment values of the member ends vary greatly under the action of asymmetric loads. The advantage is that there are fewer members that intersect at the nodes, and the construction and manufacturing are convenient.

(1) By the balance system, fey + fby-40-60 = 0n (fey represents the vertical support reaction force at point e).

fby*15+40*20+60*5=0n*m (find the moment of bending the shirt at point e), and calculate fey=

2) Vertical section of the truss H-G section is dissected and stress analysis is carried out

fh-g+f2+f1*cos45=0 (the sum of transverse stresses is 0); The sum of the vertical stresses is 0); fh-g*5+60*5-f1*sin45*5=0 (me=0), the above three formulas are obtained f1=tensile force), f2=Danzen dust tension). According to the law of the two-force rod, it is easy to tell that it is a zero rod and the f3 stress is 0.

Structural characteristics: The force of each member is mainly unidirectional tension and compression, and the bending moment and shear force distribution can be adapted to the internal structure through the reasonable arrangement of the upper and lower chords and web members. Due to the self-equilibrium of the tension and compression forces in the horizontal direction, the whole structure does not produce horizontal thrust on the support.

The structure layout is flexible and has a wide range of applications. Compared with the solid belly beam, in terms of bending resistance, the tension and compression sections are concentrated at the upper and lower ends, and the internal force arm is increased, so that with the same amount of material, greater bending strength is realized.

The above content reference: Encyclopedia - truss structure.

The advantages of trusses are:

Reliability: The design of the truss can ensure the correct installation of key components, providing high reliability assurance, and the frame can also support greater bearing capacity.

2.Flexibility: The modular form of the framework can make the system easier to expand and maintain, and in general, a new system can be rebuilt, or a new power cavity can be added in the form of modules to improve development efficiency.

3.Anti-interference: The parameter settings between the frame-mounted and the load-bearing modules can be anti-interference, and the system can also carry out more precise work.

4.Save development time: The system with frame design can save a lot of development time, and Wu Yuchun can save a lot of development time because the virtual belt of frame design can make the work more standardized, thereby saving a lot of development time.