Papers by Keyword: Modal Analysis

Abstract: This study presents a finite element investigation of the vibration characteristics of a laminated carbon fiber reinforced polymer (CFRP) composite plate with a centrally surface-bonded piezoelectric (PZT-5H) patch under classical boundary conditions. A square CFRP plate of dimensions 300 × 300 × 3 mm with a [0/90/0/90] layup is analyzed with and without an active piezoelectric patch, considering clamped–clamped–clamped–clamped (CCCC), clamped–free–clamped–free (CFCF), clamped–free–free–free (CFFF), and simply supported–simply supported–simply supported–simply supported (SSSS) boundary conditions. Linear piezoelectric theory and steady-state harmonic excitation are employed using Abaqus/CAE 2025 Learning Edition. Modal characteristics are obtained from the first six natural frequencies, while harmonic response is evaluated in terms of peak out-of-plane displacement at the plate center under combined mechanical loading and open-loop electrical actuation. The results demonstrate that the presence of the PZT patch induces boundary-condition-dependent modifications in both natural frequencies and harmonic response amplitudes. For highly constrained configurations (CCCC and SSSS), the active PZT patch leads to a reduction in peak harmonic displacement, whereas for less constrained cases (CFCF and CFFF), a slight amplification of the response is observed. These findings highlight the strong coupling between structural boundary conditions and piezoelectric actuation effectiveness, and they establish a validated baseline for future investigations involving closed-loop control, multi-patch configurations, and data-driven optimization strategies.

Abstract: This study investigates the vibration characteristics of 3D-printed polylactic acid (PLA) cantilever beams using a hybrid analytical–numerical–experimental framework. Two low-cost sensing techniques—an MPU6050 accelerometer and a GoPro Hero10 vision-based system—are systematically evaluated against analytical Euler–Bernoulli and numerical ANSYS models. The analytical and numerical approaches show strong consistency for the first three natural frequencies (Mode 1: 10.22–10.31 Hz; Mode 2: 64.04–64.58 Hz; Mode 3: 179.34–180.95 Hz). Experimentally, the GoPro accurately captures the first mode (10.5 Hz), while the accelerometer successfully detects the first two modes but deviates in the third mode due to nonlinear mass-loading and sensor–structure coupling effects. The findings highlight both the capability and limitations of low-cost SHM tools and provide new insights into nonlinear behaviour in lightweight polymeric beams. The novelty of this work lies in its multi-method validation and explicit quantification of nonlinear deviations, offering a practical framework for accessible vibration-based monitoring.

Abstract: This paper presents a comprehensive structural, modal, and random vibration analysis of the SEAMS Payload using ANSYS 18.1 simulation tools. As a preliminary design-phase study, its goal is to perform a trade-off analysis between common aerospace materials before physical prototyping and validation. The study evaluates three aluminum alloys—5052- H32, 6061-T6, and 7075-T6—to optimize the payload frame structure for mechanical stresses encountered during launch and space operations. The analysis includes static structural loading to assess deformation and stress distribution, vibrational modal analysis to determine natural frequencies and mode shapes, and random vibration analysis to simulate launch-induced dynamic excitation. The simulation outcomes highlight the critical role of material selection in enhancing structural integrity, maximizing safety margins, and ensuring mechanical reliability of the payload in harsh launch environments.

Abstract: The laminated of composite is a material made up of multiple layers of materials that are combined together to enhance mechanical and physical properties. These materials are used in a variety of applications, including aerospace, construction, and automotive, as they provide lightweight strength and flexibility. They are typically manufactured using techniques such as pressure and heat, which allow for strong adhesion between the layers. Laminated composite materials are ideal for applications that require high performance while minimizing weight. Two types of layer arrangements (symmetric and asymmetric) were used for the composite plates. The behavior of the separated plates using two models the symmetric and asymmetric model, with the aim of verifying the natural frequency results of the composite plates derived from finite element models analysis software that provides an integrated environment for designing and analyzing models. The results were used which include the natural frequency which is in proportion to the order of the symmetry max 1459.9Hz and min 257.95Hz as for the asymmetric arrangement it was max 1539.5Hz and min 241.57. Numerical analysis has proven to give good results at natural frequency. They are characterized by their toughness and flexibility, functioning as a waterproof coating and a strong insulator, making them ideal for use as a coating or adhesive.

Abstract: A three-dimensional parametric model was employed to recreate the free response laminated composite plate constructed from different materials. Simulation of the modal analysis is powerful when extreme localized modes are of problem, and it demands dependable material structural models along with correct modelling methodologies. A classical theory-based finite element approach was created to explore the effect of material attributes upon the natural vibration behavior for thin laminated plates. The approach was validated using three-dimensional deformation findings and also achieved based on the theory's results with those derived from commercial programs, including Solidworks. The results obtained from software are in good agreement for some cases and significantly differ for free vibration and is highly dependent on the material properties and boundary conditions. For simply supported boundary condition, the results showed that the maximum fundamentals frequency was 1808.5Hz Hz for the carbon/epoxy material. An established computational technique, depending on finite element method, has been proposed for the computation of free vibration in reinforcement laminated composite components. a good result for estimate the natural frequency and mode shape.

Abstract: Electronic equipment is exposed to rough vibrations throughout its life cycle. Electronic components can be damaged by these vibrations and could lead to device failure. The conventional Printed Circuit Boards (PCBs) that form the foundation of numerous electronic devices are predominantly constructed from copper films that are bound to fiber epoxy laminates, such as FR4, which is composed of glass fibers, and FR1, which is composed of paper. Being biodegradable makes cellulose a more sustainable choice. Nonetheless, it is imperative to uphold performance criteria, and this work aims to contribute to this assessment. Using simulation studies, we compare the behavior of these two PCBs under vibrational stress. The finite element analysis (FEA) of the vibrations for the PCB samples was modelled using the Ansys software. The FEA simulations show that both types of PCBs have similar movements and accelerations at certain places on the board.

Abstract: This paper presents a comprehensive modal analysis of a 15-meter span footbridge constructed using fiber-reinforced polymer structures (FRPs) integrated with natural resource fibers and a partial bio-based resin. The bridge was erected at the Floriade Expo 2022 located in Almere, the Netherlands. The lightweight nature of FRPs, coupled with their sensitivity to vibrations, necessitates the satisfaction of specific design requirements to ensure the safety and comfort of pedestrians. The initial phase of this study entails determining the natural frequencies of the bridge via Finite Element Analysis (FEA). Comparative assessment between the footbridge's natural frequency and excitation frequencies evaluates the risk of resonance induced by pedestrian loading. The FEA employs a composite layup technique to replicate the same ply configuration as the actual bridge model. Following the initial assessment, a comprehensive analysis is undertaken to meticulously examine the dynamic response of the footbridge. This analysis prioritizes the evaluation of critical acceleration parameters under diverse conditions, encompassing scenarios such as walking, jogging, and crowded pedestrian traffic. Bridge peak acceleration is assessed and juxtaposed against design values based on site usage, route redundancy, and structural height, and for the target bridge is 0.77 m/s². The results indicate that the footbridge successfully fulfills the specified design criteria for ensuring pedestrian comfort under various dynamic loading conditions. This finding underscores the significance of including the footbridge in the building application process. This study underscores the successful application of FRPs, augmented with natural fibers and bio-based resin, in ensuring the structural integrity and comfort of footbridges subjected to real-world dynamic conditions.

Abstract: Modal analysis of a quasi-isotropic Fiber Reinforced Polymer (FRP) composite plates having different cut-outs is numerically investigated under free-clamped boundary conditions using ANSYS 2023 R1. First six natural frequencies & corresponding mode shapes are extracted from the simulation. To verify the numerical results, experimental modal analysis is carried out on a sample specimen made of epoxy/glass composite with traditional ‘strike method ‘to determine the frequency response functions and to measure the natural frequencies. Investigation was continued to understand the effect of fiber orientation and systematically altered length to breadth ratio (size ratio - a/b) on the natural frequencies and the respective mode shapes. Obtained results exhibited that the correctly chosen fiber orientation contributes to improved dynamic performance, which delivers greater flexibility in designing structures to meet the application requirements. Furthermore, optimization of cut-outs was performed to demonstrate that variation in cut-outs is a key parameter and can be used to attain essential vibration mode shapes and definite frequencies. It was found from the investigation that circular cut-out acts a vital role for attaining desired free modal characteristics.

Abstract: The monitoring of dynamic parameters of slender bridge structures is becoming of particular interest in terms of their possible use in determining their structural condition, or possibly as one of the parameters for their long-term monitoring. The method for monitoring dynamic parameters is relatively new and practically unexplored. First of all, it is necessary to find out with certainty how the dynamic parameters of slender bridge structures change, for example, with changes in temperature, the magnitude of the prestressing force, or how they change with changes in discontinuous mass (e.g. overlaying or stripping of pavement layers). The paper summarizes the important aspects that can affect the modal parameters - natural frequencies and their shapes. The above listed influences and their impact on the structure were investigated on real structures formed by stress ribbon.

Abstract: This is a preliminary study to assess the mechanical behavior of an elevator car frame made of steel components, through dynamic identification. Final element models considering different restraint conditions on element nodes are taken into account to evaluate how the whole performance of the structure is affected by local connections.