What was the challenge or problem to be solved?
In certain industrial environments, failures in lighting components can lead to issues that go beyond simple loss of functionality. The appearance of cracks or fractures in structural elements compromises both system safety and in-service durability. In this case, following the integration of new components into the lighting system, recurrent failures began to be detected in critical fastening areas, generating uncertainty regarding their origin and evolution.
This situation represented a significant operational risk, as the recurrence of failures could result in field incidents, costs associated with corrective maintenance, and a potential deterioration in perceived product quality. In this context, it became necessary to carry out a study that would enable understanding the origin of these defects and defining a solid technical criterion for their mitigation, supported by INFINITIA’s expertise in industrial forensic engineering.
Crack initiation mechanisms in polymer lighting components
The analyzed system consisted of lighting elements integrating polymer materials in combination with metallic components, particularly in fastening areas. This type of configuration is common for cost and functionality reasons, but it introduces additional complexity from both mechanical and thermal perspectives.
The detected failures manifested as localized cracks, mainly at stress concentration points. These cracks did not appear immediately after assembly but evolved over time, making early identification difficult and complicating direct association with a specific cause.
Delayed crack initiation often indicates the presence of internal stresses not released during manufacturing or assembly. This type of failure is not immediate but is critical in terms of durability.
From the client’s perspective, the main need was to understand whether these failures were related to design, assembly processes, or the intrinsic behavior of materials under service conditions. The ultimate goal was to prevent recurrence and improve the reliability of the lighting system.
Identification of critical variables in industrial lighting system failures
The objective of the project focused on determining the origin of failures in lighting components by identifying the mechanisms responsible for crack initiation and propagation. To achieve this, it was necessary to establish a clear relationship between service conditions, component configuration, and the properties of the materials involved.
Beyond identifying the failure, the aim was to provide a technical basis to support informed decision-making, whether in terms of redesign, material selection, or adjustments to the assembly process. This required an approach integrating multiple disciplines, from material characterization to mechanical analysis of the system.
Additionally, the study needed to anticipate the future behavior of the components, assessing whether the problem could worsen over time or under certain environmental conditions. This aspect was critical to ensure system durability and prevent medium- and long-term incidents.
Stress concentration analysis in polymer-metal joints
One of the main challenges of the project lay in the complexity of the system, where materials with significantly different mechanical behaviors coexisted. The combination of polymers and metals in joint areas frequently generates internal stresses due to differences in thermal expansion coefficients, stiffness, or assembly conditions.
These stresses may remain latent for a period and later manifest as cracks, especially in the presence of additional factors such as mechanical loads, thermal variations, or microstructural defects. This type of failure, associated with structural stresses, is particularly difficult to diagnose without an appropriate analytical approach.
Joints between materials with different mechanical behavior are common failure points if not properly managed. Differences in stiffness and expansion generate stress concentrations that are difficult to predict.
In this context, INFINITIA had to address the challenge of identifying not only the failure location but also the mechanism that caused it, without relying on simplified assumptions. This required a detailed analysis of the interaction between materials and service conditions, maintaining a balance between technical rigor and industrial applicability.
How was it addressed or what was the solution?
To address the problem of failures in lighting components, a strategy was defined based on the combination of different analysis techniques aimed at characterizing both the material and the system behavior under representative conditions. This approach enabled a comprehensive understanding of the problem, avoiding partial or biased interpretations.
INFINITIA’s intervention focused on applying methodologies typical of industrial forensic engineering, integrating laboratory analyses with tests designed to reproduce the failure. In this way, the objective was not only to identify the cause but also to validate the proposed hypotheses under controlled conditions, increasing the reliability of the conclusions obtained.
Fractographic characterization of fracture surfaces in polymer materials
The first phase of the work focused on the detailed study of fracture surfaces, with the aim of identifying characteristic patterns that would allow inference of the failure mechanism. Fractographic analysis is a key tool in this type of study, as it provides direct information on crack evolution.
Through observation of the fractured surfaces, aspects such as crack morphology, the presence of initiation zones, and propagation direction were evaluated. These elements allow differentiation between brittle, ductile, or stress-induced failures.
This analysis enabled the formulation of an initial hypothesis regarding the origin of the failure, linking it to the presence of internal stresses in the material. However, this hypothesis needed to be validated through additional testing to ensure its reliability.
Evaluation of residual stresses and mechanical behavior in engineering polymers
In parallel, the physicochemical properties of the polymer material used in the components were characterized. This analysis made it possible to assess whether the material exhibited features that could promote crack formation under certain conditions.
One of the key aspects was the identification of potential residual stresses generated during manufacturing or assembly processes. These stresses, although not always visible, can act as triggers for failure when combined with external factors.
The material study allowed certain potential causes to be ruled out and reinforced the hypothesis that the origin of the problem was related to the interaction between component design and assembly conditions.
Experimental reproduction of failure through controlled accelerated testing
To validate the proposed hypotheses, specific tests were designed to reproduce the failure under controlled conditions. This type of testing makes it possible to verify whether the identified mechanisms are truly responsible for the observed behavior in service.
Reproducing the failure under controlled conditions is essential to validate hypotheses and avoid incorrect conclusions. Without this validation, the diagnosis may remain an unproven correlation.
By applying loads, thermal conditions, or assembly configurations similar to real conditions, the aim was to induce crack formation in the analyzed components. Failure reproduction constitutes strong evidence to confirm the root cause of the problem.
As a result, a more complete understanding of the phenomenon was achieved, enabling a clear relationship to be established between structural stresses and crack formation. This knowledge provides significant value to the client, facilitating decision-making aimed at improving system reliability and durability.
