How Should the Structural Design of Refrigerated Containers Be Optimized?

Refrigerated containers come in many sizes and can be customized, so how should their structural design be optimized? Our company has found that the overall principle of structural optimization is to meet ISO standards and the box owner's basic strength requirements for the container body, then optimize according to strength test results and the equal-strength design principle, greatly reducing the container weight. Where deformation is large, strength should be increased; where strength is excessive, it can also be reduced appropriately. In design, make full use of the principle that folding ribs into flat plates greatly improves strength, and use different bending methods to meet the strength requirements of each part—especially for thin-plate ribbing. With a sound design, the corresponding extra reinforcement members can be omitted. (1) In design, the door opening of a refrigerated container should be enlarged as much as possible to make transport convenient for the box owner; stiffness along the container length can be improved to ensure rigidity; (2) After the refrigeration unit is connected, strength and stiffness increase, so the design should take full advantage of this—end-frame panel thickness can be reduced appropriately to cut weight; (3) To enable the container body to withstand larger external impacts and prevent dents or deformation, thicker steel plate is recommended for the outer skin and thinner plate for the inner skin, which neither changes overall strength and stiffness nor increases material use. For example, outer corner posts should be designed thicker than inner corner posts. Strength design should also consider the relationship between container service life and corrosion; (4) To achieve smooth cold-air circulation inside the box, when designing the inner-wall rib structure, avoid as much as possible high lines from the cold-air outlet to the upper floor surface and resistance and pressure loss in the T-FLOOR channels on the floor surface. Therefore, changes in air-duct cross-section must be reduced to prevent local eddies that disrupt airflow. At the same time, right-angle bends should be reduced to cut pressure loss; return-air openings should be enlarged as much as possible, especially above the cargo height-limit line—the less the return-air openings are blocked, the better, provided other performance is not affected. An anti-scuff plate can be added at the lower part of the inner panel; riveted splash guards may be used, and anti-scuff capability can be increased at higher positions without affecting appearance; the outer roof is the main waterproof component. During transport, the outer roof often dents, or, due to insufficient roof-panel strength, dents under self-weight and inertia. As a result, water easily pools on the outer roof for long periods and rust readily forms. During manufacture, the outer roof should be raised 3-5 mm at the center; during assembly, the mid-span support should leave the outer roof slightly convex to aid drainage.