In modern logistics equipment, warehouse shelves as a kind of important storage equipment more and more used in all walks of life, reasonable design, choose the shelves to become more and more important work. And beam as an important component of the combined shelf, how to choose the scientific is also a need to solve the problem. The following Shenzhen shelves to talk about the ability to withstand the test and calculation of the shelf:
1, the cargo lattice model of goods to simplify the storage of goods for the smallest unit, consisting of beams and columns. The research of the model is to analyze the stress model of cross beam.
In practical applications, the beam span of the combined shelf is concentrated between 10004000 mm. Smaller span beams are generally used for light and small goods shelves, goods to bulk materials and small packing goods mainly, and placed directly on the beam. At the same time, in order to prevent the goods from contact and collision, the two ends of the goods placed area are provided with a certain lateral clearance.
For large span beams, mainly used for medium and high and heavy goods shelves, cargo first code on the tray and then placed on the beam, and the use of forklift, crane and other handling equipment to achieve access to goods. In order to prevent the goods from collision and facilitate access to the operation, between the goods and the goods and the column between the set of a certain safety clearance. At the same time, considering the universality and practicality of the model, the prices of goods in accordance with each beam span larger goods lattice placed 2 tray calculation, even if the use of the actual situation in the 3 or 1 tray tray, through experimental checking, error is acceptable.
Considering the uniformity of the arrival model, the lateral clearance, the horizontal clearance, the pallet length and the value of the cargo lattice length are considered.
2. The free degree of the beam is a space truss structure, but the calculation model is simplified as a plane model when calculating the beam load. Because the span of the combined heavy goods shelf beam is much larger than the cross section size, the beam can be simplified as beam element in material mechanics, and the restraint of the two ends of the beam is the key point of the research.
Each end of the beam has 3 degrees of freedom, namely rotation of X axis, Y axis and the translational motion around the Z axis, the usual approach is to both ends of the beam as a hinged or fixed end. As the hinged end processing, constraints of the 2 endpoints of the translational degrees of freedom, rotational degree of freedom but is not limited to the endpoint. In this state, the beam is at the endpoint relative to the original axis torsion angle, the endpoints can transfer the force can not transfer torque; when treated as a fixed end, the constraints of the two ends of the beam. All degrees of freedom. The beam at the endpoint can be neither translational can not rotate, but can transfer the force and moment.
Combined shelf beam and column adopt a special plug and plug connection mode, and the cross beam is inserted into the hole of the upright post through 3 claws or 4 jaw hanging pieces. This connection mode on the one hand to allow the beam around the axis of the force has a certain rotation, on the other hand, the end of the beam to the end of the beam can be transferred to the load on the column of the moment. Thus, it is not in line with the actual situation to simplify the two ends of the beam to a simple hinged end or a fixed end. The actual effect of the beam is part of the hinge support.
If the total beam load is W, the actual deformation of beam is equal to the partial load (pW) at the hinge condition caused by beam deformation and residual load ((1- P) W) caused by the beam deformation in the clamped condition, i.e. y= y i + y g, y for the actual deformation of the beam. Y J pW the size of the load at the hinge beam deformation under the conditions of Y, G (1- P) W in the size of the load deformation of beam clamped, P share is hinged under the condition of bearing beam percentage, can be obtained by experiments, this paper take p= 071.
When the deformation of the beam is known to be the load of the beam, the linear relationship between the deformation and the load is W= 071 J W + 029 g F.
Among them, the W for the beam bearing, G W for the hinge support under the condition of deformation of the beam bearing, G W for the fixed condition under the deformation of the beam bearing F.
Bearing the load beam 3, load refers to the 1 of the same beam under the load of goods, but in the process of calculation because we only take 1 beams as the research object, the loading of the goods is 12 load bearing beam. Because the beam is made of high density steel and iron material, the span is larger, so the influence of the weight of the cross beam must be considered in the calculation.
When the beam span is small, the goods for bulk materials and packaging of small items and placed directly on the beam, we can put the cargo load as the uniform force loaded on the beam central and lateral distance from the left column certain; for beam weight, according to the uniform force loaded on the whole beam,. When the span of the beam is larger, the goods are put on the cross beam through the tray. Generally, the tray and the beam contact line contact and non contact parts of the goods force on the beam on the tray and non uniformly distributed over the entire tray, so in the simplified load on each tray of the goods in accordance with the centralized loading tray in 2 legs, each a concentrated force for the whole beam bearing 1/ 8 for beam weight, still in accordance with the uniform force loaded on the whole beam. Figure a 1 side gap, a 2 level gap, Q beam weight load, Q 1 for the goods in accordance with the calculation of the load uniformly distributed load G/ 8 for goods, goods loading each concentration calculation according to the pallet support foot cargo loading.
Force model 4 calculation method for large span beam of small span beam