Elements with a porous structures are quite common in nature. They are also starting to gain more and more recognition in engineering. They allow you to achieve the desired stiffness with a significant reduction in weight and relatively acceptable geometric dimensions. However, unlike solid materials, they require more complex engineering calculations carried out in design and simulation processes. The article presents the possibility of using the lower bound method to determine the limit capacity of structural elements with a porous structure. The concept of limit capacity is presented and an attempt to use it to solve the problem of a porous strip in tension and bending. Isotropy of the structure was assumed. The issue is considered in the context of the possibility of using it to assess the strength of structures obtained using the Fused Deposition Modeling method.