Recently, the production of metal structural elements using additive processes is gaining popularity. They allow the production of an element of any geometry and structure, while reducing the mass of the produced part. Unfortunately, the AM technology causes structural elements to be burdened with numerous defects in the form of porosity, unmelted powder, weak interlayer bonds or residual stresses, etc. These defects translate into the possibility of an early, uncontrolled fatigue crack. For this reason, it is important to find ways to quickly detect damage caused by random variable loads. The work presents methods of diagnosing cracks and fatigue damage in structural elements produced using 3D printing. The division of research methods allowing for the detection of defects in structural elements and the characteristics of the most popular methods, taking into account their advantages and limitations, were presented. Methods appropriate for a given type of material, test conditions and damages are indicated. The most important methods of diagnosing defects in printed elements include: penetrating, ultrasonic, radiographic, eddy current and thermal imaging methods.

The paper presents the applications of glued joints in many industry branches. The advantages and disadvantages of glued joints as well as the methods of detecting weld damage are presented. The methods of damage analysis to the glued joints were divided and explained. The most important detection techniques are the X-ray method, the ultrasonic method, the Laser Ultrasound method, the guided wave method, the electromechanical impedance method and the active thermography method. The advantages and limitations that may allow for the proper selection of the research method depending on the diagnosed material and the conditions accompanying the study were indicated.