Design of fixing PVC tile, plastic steel tile and PVC plastic steel tile products
1. Stress strain relationship PVC plastic steel tile has viscoelastic deformation, in addition, it has a yield point (which is similar to wood and brittle metal), and in addition, PVC plastic steel tile has small ductility, so it does not have the same effect as ductile metal to ease the stress concentration near the notch or hole. This characteristic must be taken into account when considering the safety factor.
In addition, the above reasons will inevitably lead to local stress concentration and uneven stress distribution. Such as PVC plastic steel tile board Mounting holes screw High stress concentration occurs around grooves and steps. However, the information about the stress concentration of PVC plastic steel tile materials is still lacking. Taking circular hole as an example, due to the anisotropy of PVC plastic steel tile, the stress concentration generated by it is much larger than that of isotropic plate, which must be taken into account in design.
z. Low usability PVC plastic steel tile has high specific strength and low specific rigidity. Generally, the main elastic modulus of two-way FRP is only 1/14 of steel or 1/5 of aluminum. Even the unidirectional PVC plastic steel tile with 80% fiber, the elastic modulus of the front main direction is only 1/4 of the steel. The elastic modulus of isotropic PVC plastic steel tile is even lower than that of wood. Even if the strength of glass fiber reinforced plastic structure is sufficient, it is easy to produce large deformation due to insufficient rigidity.
The design measures to improve the rigidity are: sandwich structure, such as honeycomb sandwich or foam sandwich, reinforced with frame or embedded with metal parts. For products requiring high impact strength, low elastic modulus and high degree are beneficial.
a. Anisotropic metal materials are all homogeneous isotropic bodies. For Borui steel, its various characteristics have directionality. Only short cut fibers or PVC plastic steel tile mat laminates are similar to sub isotropic bodies. The PVC plastic steel tile fiber fabrics we use in hand lay up molding are generally anisotropic because of their different material preparations in the vertical and plane directions. If the product needs to be isotropic, it is necessary to select appropriate PVC plastic steel tile and design a reasonable paving method. If unidirectional reinforcement is required, cloth or unidirectional belt with different warp/weft ratio can be selected.
4. Dynamic characteristics The PVC plastic steel tile is different from the metal material and has viscoelasticity. Under the action of dynamic load, it is very different from other materials in deformation and strength. The so-called dynamic characteristics here refer to impact strength, fatigue strength and creep failure strength. The impact strength of fixing PVC plastic steel tile is much smaller than that of metal, while the larger elastic value (recovery) is much larger than that of metal. That is, PVC plastic steel tile material itself has the effect of absorbing impact energy. In addition, PVC plastic steel tile material has the property of flat deformation at room temperature, so its strength and elastic modulus change with the load action time. Moreover, the vibration attenuation rate of PVC plastic steel tile is large (about twice that of metal), which is often considered as an advantage when used in structures.
