FEM analysis for Telemetry Flight Test Instrumentation

PCAMI-1000 is an Airborne ruggedized Instrumentation System that handles excitation, attenuation, signal conditioning, data, embedded video and audio acquisition, encoding, operating numerous buses such as MIL 1553 and Arinc, and onboard data recording and data transmission with chassis of varied slot capacities such as 3, 6, 9 and 13 slots. Our client is a Government of India-approved aerospace and defense R&D unit. We collaborated with the client from the initial stages of the design process. Our domain expertise leveraged with Finite Element Analysis (FEA) technology has accelerated our clients Innovation process. We performed modal analysis, Vibration, Sine sweep, Random vibration analysis, Shock analysis, and Acceleration analysis per military standards (MIL-Std 810H) using Finite Element Analysis (FEA) software. Our meticulous engineering practices yielded reliable analysis results, which enabled our client to explore more design options and make well-informed decisions at the appropriate stages in the product development cycle.

The PCAMI-1000 enclosure model was discretized using a combination of higher-order tetrahedral and hexahedral finite elements to accurately represent the complex geometry of the enclosure and its structural components. The finite element (FE) model consists of 1,358,886 nodes and 788,598 elements, providing a detailed representation of the assembly for subsequent structural and dynamic analyses. Higher-order elements, which incorporate additional nodes along their edges, enable improved representation of curved surfaces and complex deformation patterns compared with linear elements, particularly when the mesh quality is appropriate. Tetrahedral elements were used to accommodate geometrically complex regions, while hexahedral elements were employed in suitable regions of the model. Furthermore, appropriate contact definitions were established between the individual components to represent their interfaces and facilitate load transfer throughout the assembly. These contact interactions help capture the structural behavior of the assembled enclosure under applied loading conditions and provide a reliable foundation for subsequent finite element analyses, including modal, vibration, shock, and acceleration studies.

Modal analysis was performed on the PCAMI-1000 enclosure to determine its natural frequencies and corresponding mode shapes over a frequency range of 0–2000 Hz. The analysis identified 72 natural frequencies within the specified range, providing insight into the dynamic characteristics of the enclosure. The mode shape plots for the first six modes were examined to understand the deformation patterns associated with each natural frequency and to identify the regions most susceptible to vibration. Additionally, the dominant frequencies in the X, Y, and Z directions were evaluated to characterize the enclosure directional dynamic response. This analysis helps identify potential resonance conditions that may arise when the excitation frequencies during flight operations coincide with the natural frequencies of the structure. The results can therefore be used to assess the enclosure dynamic behavior and support design modifications, if required, to improve its structural integrity and vibration resistance under flight-test operating conditions.

Acceleration analysis was performed on the PCAMI-1000 enclosure by applying a load of 15 g in each of the X, Y, and Z directions to evaluate its structural response under the specified inertial loading conditions. The corresponding deformation and stress contour plots were generated to assess the displacement patterns and stress distribution throughout the enclosure assembly. The analysis focused on critical structural components, including the bottom panel, power supply panels, and side panels, to identify regions experiencing higher stress levels. The results indicate that the stresses developed in all components of the assembly remain well within the permissible limits for the specified loading conditions. This confirms that the enclosure exhibits adequate structural strength under the applied acceleration loads. The analysis also helps identify potential areas of stress concentration and provides confidence in the structural integrity of the PCAMI-1000 enclosure under the evaluated operating conditions.

Random vibration analysis was performed on the PCAMI-1000 enclosure along the X, Y, and Z axes in accordance with the specified vibration loading profile. The finite element method (FEM) was used to evaluate the structural response of the enclosure under random vibration loading and to determine the resulting stress distribution across the assembly. The corresponding stress contour plots were examined to identify critical regions and assess the structural behavior of individual components, including the bottom panel, power supply panels, and side panels. The analysis results indicate that the stresses developed in all components remain within the permissible limits for the specified loading conditions. This demonstrates that the enclosure has adequate structural strength to withstand the evaluated random vibration environment. The results also help identify potential stress concentration regions and support the assessment of the overall structural integrity and reliability of the PCAMI-1000 enclosure under the anticipated flight-test operating conditions.

Finite Element Method (FEM) analysis has been conducted on the PCAMI-1000 Airborne ruggedized Instrumentation System, taking into account acceleration and random vibration loads in the x, y, and z axes. The results of the FEM analysis indicate that the stresses encountered by all components of the assembly, such as the bottom panel, power supply panels, and side panels, are comfortably within the allowable limits for the defined loading conditions.