## 4. Constructional and Functional Aspects of Chains
### Link Shaping and Geometry  
The shaping and geometry of chain links -- particularly those intended for use in demanding environments-- are closely tied to the chain's functionality and mechanical strength. In the design process, special attention is given to the link shape, which must ensure sufficient geometrical adaptability during operation without compromising load-bearing capacity. The geometry of the links directly influences how loads are transmitted and how the chain resists mechanical wear and damage.  
Properly designed link geometry helps to avoid stress concentrations, deformation, and strain under load. To optimize the design, three-dimensional modeling and Finite Element Analysis (FEA) can be applied. Such simulations enable identification of stress and strain distribution patterns under various loading conditions, highlighting areas with maximum and minimum intensities.  
In technical chain design, the configuration of the link layout must also follow ergonomic and efficiency principles. An excessive number of links increases chain mass unnecessarily, raising production costs and reducing the efficiency of the transport sys  
Figure 8: Chain anchorage setup for static tensile testing according to ISO 610 [106], showing specimen view (**a**), cross-section of insert (**b**), and insert detail (**c**).  
tem. Conversely, improper link geometry may result in premature wear and eventual system failure.  
Link geometry is also affected by manufacturing technology and processing methods. Depending on the material used, engineers encounter different production challenges--particularly in the case of polymer chains. Therefore, designers must account for specific issues such as bending angles and inter-link interaction under load. Advanced engineering tools such as computer simulations allow for the precise definition of optimal link dimensions to ensure functionality and durability.  
Various software platforms can be used for this type of analysis--SolidWorks 2025, for example, is a widely applied tool [113]. It facilitates the visualization of displacements, deformations, and stress distribution. The overall chain strength is largely determined by the contact zones between individual links and their geometry. In tensile testing, stress concentration is greatest across the horizontal section of the link. As illustrated in Figure 9, the most highly loaded zones are the contact surfaces. Surface imperfections, such as notches or irregularities, can significantly reduce the link's strength, thereby weakening the entire chain.  
Torsional deformation of the chain is particularly detrimental, as it alters the orientation of the contact zones, forcing the link to operate under non-optimal conditions and leading to premature failure under loads lower than the nominal breaking force [114]. Therefore, properly defined tolerances and clearances--allowing controlled relative motion between links--are essential to ensure effective and safe chain operation.  
Finite element optimization (SolidWorks Simulation 2024) shows that enlarging the internal filet radius from 0.2 d to 0.35 d in PET/GF links lowers peak von Mises stress by 28% while adding <3% to mass. Controlled fountain flow during mold filling further produces fiber-rich skins that suppress notch-sensitivity and brittle fracture. These observations will inform upcoming patent submissions on graded-structure links