Browse Topic: Analysis methodologies

Items (9,930)
AMS6885/2 gives specific information about the qualification program for unidirectional carbon fiber tape epoxy repair prepreg capable of curing under vacuum for repair of carbon fiber reinforced epoxy structures. The prepreg system shall include an epoxy film adhesive to be applied in a co-bonding process with the prepreg for solid laminate and sandwich bonding.
AMS CACRC Commercial Aircraft Composite Repair Committee
Alloy wheels are essential safety components in two-wheeled vehicles. This study details the finite element analysis (FEA) used to simulate and evaluate the wheel and tire performance under the double mass impact load specified by the AIS-073 (Part-1) standard. The impact is carried out by dropping a striking mass along with a main mass onto the alloy wheel–tire assembly, as per the standard. The alloy wheel is modeled using a three-dimensional finite element model with elastic-plastic material behavior, and the tire is modeled with its internal elements (e.g., carcass, belt, etc.). The prediction of wheel impact failure is based on the total plastic work of the ductile fracture mechanism. The validity of results is confirmed by comparing the predicted permanent lateral rim deformation against the measured lateral deformation from a corresponding physical test.
Minz, Jai ShankarSingh, Sanjay KumarNirala, Deepak Kumar
This AIR provides a general guideline on how to perform effective measurement systems analysis study (MSA) for rotor balancing tasks. The document also includes applicable data analysis methods and result interpretation.
EG-1A Balancing Committee
Heavy-duty vehicles significantly contribute to greenhouse gas emissions and urban air pollution, especially during cold-starts and transients when engine and aftertreatment efficiencies drop. Waste heat recovery (WHR) via Organic Rankine Cycle (ORC) systems offers a practical solution to improve fuel efficiency and cut CO₂ in real-world heavy-duty operations. This study examines ORC-based WHR integration into conventional and hybrid powertrains of an Isuzu FTR850 truck, analyzing four configurations: Shell-and-Tube or Plate heat exchangers with simple or regenerative ORC layouts. For hybrids, it compares two engine sizes and energy management strategies: an optimized fuzzy logic approach versus constant-power operation to enhance exhaust heat recovery. A validated quasi-static simulation framework is used to predict fuel consumption and exhaust properties over representative duty cycles. 2D performance maps using exhaust temperature and mass flow as inputs are used to model the WHR
Donateo, TeresaMorrone, Pietropaolo
This study investigates the structural improvement of recycled carbon fibre composites through hybridisation with continuous flax fibres to address sustainability concerns and performance limitations. Recycled carbon fibres, while environmentally beneficial, suffer from short, randomized orientations and lower mechanical properties limiting their application beyond decorative uses. This research explores whether incorporating unidirectional flax fibres can enhance rCF behaviour for structural applications. Six hybrid composite layup variants and two plain composites were manufactured using cold compression moulding with Ampro Bio Resin. Each hybrid configuration comprised eight layers, divided into four layers of recycled carbon and four layers of flax fibres oriented at 0°. Complete mechanical characterization was performed following ISO standards for tensile (ISO 527), flexural (ISO 178), and impact (ISO 179) testing. Results demonstrated significant performance improvements in
Hnatyk, DawidChrysanthou, AndreasDe Vuyst, TomIsmail, Sikiru
Sealing systems in space applications must perform reliably under demanding conditions in engineering: cryogenic temperatures, vibration, leakage control, ultra-high vacuum, ionizing radiation, abrasive particulates, and repeated thermal cycling. Each factor strains conventional sealing technologies. In combination, they can rapidly cause failure in systems where margins are unforgiving and maintenance is impossible. As spacecraft architectures evolve toward longer operational lifetimes and broader mission profiles, sealing requirements continue to tighten. Launch vehicles, satellites, and exploration platforms now operate across wider temperature ranges and in contact with more aggressive propellants and media. As a result, both metal seals and engineered polymer alternatives are evaluated-and selected-against increasingly specific, measurable performance criteria.
This study presents a comprehensive methodology for optimizing critical UAV structural nodes—specifically Arm Clamps, Landing Gear, and Motor Mounts—using Generative Design (GD) tailored for Fused Filament Fabrication (FFF) with PLA+. Traditional “plate-and-standoff” UAV constructions often utilize orthogonal geometries that induce stress concentrations and fail to leverage the geometric freedom of additive manufacturing. Furthermore, reliance on expensive CNC machining or injection molding creates supply chain bottlenecks for custom or short-run UAV production. While FFF offers geometric freedom, applying it to structural airframe parts introduces challenges regarding anisotropy, layer adhesion, and material brittleness. This research optimizes these components for standard commercial 3D printers by strictly enforcing manufacturing constraints, including a 40-degree maximum overhang and a 0.4 mm nozzle size, to ensure printability without internal support structures. A significant
Krishna Bansal, Vaibhav
Dynamic responses at critical locations of a spacecraft due to excitations expected during the ascent phase of a launch vehicle mission are usually estimated through a Coupled Loads Analysis (CLA) using the structural dynamic finite element model of the launch vehicle coupled with that of the spacecraft. Generally, the full physical structural dynamic model of a spacecraft has lakhs of degrees-of-freedom (DOFs). Coupling such a model with a similar model for the launch vehicle results in exorbitantly high computational costs for CLA. Hence, dynamic analysis of such large and complex structural assemblies usually employ sub-structure coupling or Component Mode Synthesis (CMS) methods. The most widely used CMS method for dynamic analyses is the Craig-Bampton (CB) method. Conventionally, a full launch vehicle CLA involves one level of CB-reduction wherein a reduced-order dynamic model of the spacecraft is first generated using the fixed-interface CB-method. This reduced-order model is
Ramachandran, Nirmal
This study presents a data-driven approach for strengthening aviation safety by integrating human factors assessment with modern predictive modeling techniques. The work focuses on understanding how human performance, operational conditions, and system-level interactions collectively influence safety risk, and how these interactions can be quantified to support improved design and decision-making. Unlike previous studies that address human factors or predictive modeling in isolation, this research offers a unified framework that links causal human factors indicators with statistical modeling, feature extraction, and machine learning based risk estimation. The novelty of this work lies in the structured pipeline that transforms raw categorical and narrative human factors information into measurable predictors that can be analyzed using structural modeling and machine learning. The methodology includes data preparation, dimensionality reduction, latent pattern discovery, dependence
Valiyaparambil, Praveen
Polymeric optical materials such as Cyclo Olefin Polymer (COP) are adopted in aerospace lighting systems due to their excellent optical clarity, dimensional stability, moldability and weight saving advantages over glass. However, their relatively low toughness and the presence of residual molding stress make them prone to crack initiation during mechanical fastening. During its installation, crack formation was consistently observed around self-tapping screw interfaces, raising concerns over reliability, maintainability, and compliance with durability requirements. A structured Design of Experiments (DOE) was performed to identify root causes and evaluate potential mitigation methods. The investigation revealed that residual stresses in the COP material, combined with localized stress concentrations during screw tightening, were the primary drivers of crack initiation. Two complementary process improvements were identified and validated as part of mitigation plan: (i) annealing of the
S, NikhilSingh, Abhimanyu KumarKatageri, PraveenSP, PradeepChandra, Praveen
Unscheduled maintenance due to the failure of critical components, such as aero-engine rolling element bearings, is a leading cause of costly Aircraft-on-Ground (AOG) events; consequently, current time-based maintenance practices are inefficient and prone to risk. This paper develops a resource-efficient Hybrid Digital Twin (HDT) model for an engine bearing, focusing on the dynamic prediction of spall growth due to Rolling Contact Fatigue (RCF), thereby enabling a condition-based maintenance paradigm. The HDT architecture integrates two core models: (1) a physics-informed model that uses established life and fatigue theory to define initial degradation thresholds, and (2) a data-driven Recurrent Neural Network (RNN), specifically a Long Short-Term Memory (LSTM) network, for dynamic degradation rate modeling. The methodology utilizes a Monte Carlo simulation coupled with RCF progression equations to generate a large, high-fidelity synthetic run-to-failure dataset under varying
Mohamed, Abbas
Porosity in carbon fibre reinforced polymers (CFRP) remains a critical concern for aerospace engineers, as even minor voids introduced during manufacturing can undermine the reliability of structural components. This work explores the influence of Interply porosity on composite panel behavior, employing a multiscale simulation approach that bridges material characterization and full-scale structural analysis. The study begins with virtual coupon testing using Digimat-VA and Digimat-MF, enabling the prediction of material allowable and the assessment of defect variability. Homogenized material properties derived from these simulations are then applied to detailed panel models constructed in MSC Apex, ensuring accurate representation of layup and orthotropic behavior. The workflow can support a range of structural load cases, allowing for the evaluation of stiffness, buckling, or other relevant scenarios as dictated by aerospace certification requirements. Nonlinear finite element
Savane, VishalKumar, Rajat
Grid fins are non-conventional aerodynamic lifting and control surfaces which are made of a frame supporting lifting surfaces positioned in the form of a lattice structure. Grid fins are also called as lattice fins and are used as control surfaces in launch vehicles, crew escape systems, missiles etc. to achieve static stability. Each panel of the grid fin acts as fin and it produces force which increases stability of the vehicle. For a crew escape system module, grid fins are used as a passive aerodynamic control surfaces to achieve static stability. Grid fins are positioned at the end of crew escape system module to provide required static margin by increasing moment arm. In contrast to conventional fins, grid fins incorporate a distinctive waffle-like pattern or grid pattern configuration, offering superior aerodynamic performance in supersonic regimes and enabling compact storage in stowed position during launch followed by deployment at the time of exigency. In case of an
Mali, Somanath NanduSundar Raj, RSundaresan, MKR, Suresh
Digital engineering practices in aerospace increasingly require closely connected and traceable analysis workflows rather than isolated finite element tasks. Traditional FEA methods remain effective, but they involve considerable manual effort during pre- processing and post-processing, making rapid iteration difficult. Finite Element Analysis of STructures (FEAST), an indigenous finite element analysis software developed by Vikram Sarabhai Space Centre (VSSC) ISRO, offers structural analysis capabilities through a command-based architecture, yet its manual operation limits its use in automated studies. This work develops a flexible scripting-driven framework that links geometry creation, load-case definition, solver execution, and result interpretation within a unified digital engineering pipeline. The framework automates repetitive tasks, incorporates Design of Experiments (DoE) for systematic parameter variation, and supports sensitivity and automation studies. Its performance is
Gupta, ShivangiT J, Raj ThilakP, Deepak
The study proposes the use of Carbon Fiber Reinforced Plastic (CFRP) sandwich composites configurations for structures interfacing cryogenic tankages. To address the design challenge posed by high thermal contractions in metallic tanks after cryogenic propellant filling, the study incorporates slits near the tank interfaces. Additionally, to minimize the transfer of cryogenic temperatures into these interfacing parts, the sandwich structure features interface end attachment made of thermally insulating Glass Fiber Reinforced Plastic (GFRP) material. Analytical and Finite Element (FE) studies were conducted on a typical cylindrical cryogenic intertank structure to demonstrate the proof of concept. These studies included analytical design using MATLAB based codes, parametric analyses with simplified shell element models and detailed 3D sector models using solid elements. The parametric studies assessed the effects of the number and dimensions of slits to achieve an optimal design, while
Bhalerao, Sandesh PopatGupta, Yogesh KumarMadhukumar, P.
The payload fairing of a launch vehicle is subjected to extremely high acoustic loads, with peak levels occurring during lift-off and transonic aerodynamic regimes. The external acoustic field penetrates the fairing, producing intense internal sound pressure levels that can challenge the integrity of spacecraft components. Accurate characterization of the vibroacoustic behavior of the payload fairing and its enclosed cavity is therefore essential to ensure spacecraft survivability. The internal acoustic field is governed by the coupled dynamics of the fairing structure and the spacecraft configuration, making it critical to quantify the acoustic environment for different payload arrangements. This study presents a detailed vibroacoustic analysis of a payload fairing with multiple spacecraft configurations to evaluate the resulting internal sound pressure distribution. Vibroacoustic finite element analysis is employed in the low frequency range, while statistical energy analysis is
S R, Arun RajJayan, MahindGeorge, P
Static electricity is an electrical imbalance on the surface of a material which can interact with other components having same or different materials. Fluid flow within the hose assembly generates static voltage due to friction caused by fluid flow in pipes, that needs to be appropriately quantified and dissipated. Accumulation of such static charge may lead to sudden discharge leading to spark generation. Spark generation around fuel flow might lead to system failure and failure in aircraft engines. Test experiments were conducted to analyze static voltage generated in hose assembly due to fuel flow with the objective that voltage achieved is within the acceptable range to avoid ESD (Electrostatic Discharge) failure. Procedure includes flow rate monitoring and voltage measurement using fuel as test fluid. The testing revealed that the curvature of the hose affects the readings, highlighting the importance of consistent meter alignment. Using a grounding strap is essential to prevent
Waghmare, Shashank
The rapid growth in the number of aircraft and pilots emphasises the need for an AI-enabled training framework that can offer precise, automated examination of flight manoeuvres. This will be useful in optimising the pilot's training efficiency and minimising iterations of the conduct of flight manoeuvres, thereby reducing the training time of the pilot for a flight. A general framework is developed that can be used for all kinds of flight phases and aircraft types. A pre-trained machine learning model is designed using a supervised learning technique, Random Forest, to recognise different manoeuvres. Various statistical parameters, such as mean, standard deviation, kurtosis, skewness, etc., of several flight parameters were used as the input features to train the Random Forest classifier. In the present work, the classifier is trained using several actual flight test data manoeuvres, and is also supplemented with simulated manoeuvres. The achieved gross accuracy for manoeuvre
Sahu, AkashC, PoornimaC, AravindhKaliyari, DushyantTK, Khadeeja Nusrath
This paper addresses the critical challenge of fault-tolerant control in autonomous multi-copters, particularly under conditions of one or two rotor failures a scenario that often leads to severe instability and a complete loss of directional control due to unbalanced torque and resultant autorotation. Existing advanced control strategies, including optimal approaches such as LQR, typically require precise system modeling and state estimation, which are difficult to achieve in real-world, dynamic failure scenarios. Alternative methods like fuzzy logic, sliding mode control, and gain-scheduling either lack robust generalization or are impractical for enumerating all possible failure cases. In this work, a hybrid control framework integrating Physics Informed Neural Networks (PINN) with a standard PID controller is proposed for fault-tolerant operation of autonomous multi-copters subject to multiple actuator failures. PINNs incorporate governing physical laws as regularization in their
Charapalle, SamruddhiVenugopalan, NandagopalanNerkundram Muralidharan, ArunSundararaj, Laveen
The mechanical performance of short fiber-reinforced plastic (SFRP) components is highly sensitive to fiber orientation, which is significantly influenced by the injection gate location during the molding process. Traditionally, gate placement decisions are driven by warpage minimization strategies, often overlooking mechanical performance under diverse load cases. This research introduces an automated workflow within Digimat-MS that integrates injection gate optimization into the early design phase, leveraging Integrated Computational Materials Engineering (ICME) principles. The proposed methodology enables engineers to upload either Marc, Abaqus or Ansys input decks, select a component of interest, assign material cards, and define gate scenarios. A Design of Experiments (DOE) is then executed locally or remotely, allowing Digimat to evaluate multiple gate configurations. The system aggregates results and identifies optimal gate locations based on the initiation of failure under
Kauthale, TanmayMadhavan, VinaySoni, Ganesh
Gaganyaan is an ambitious and recover safety mission for the Indian space program to launch humans into space. The success of the mission depends on the development of required technology and systems. A test vehicle is developed for the technological demonstration for all envisioned abort flight scenarios of Gaganyaan mission. A new configuration of launch vehicle with single liquid stage is planned for multiple flights. Coupled Loads analysis of launch vehicle system is a standard practice to estimate response and loads for the design of structures and generating sine vibration test levels. Usually a vehicle rests on the launch pad through base shroud with horizontal support and no vertical restraint. Upon ignition of the engine, thrust builds up and upon overcoming gravity the vehicle takes off. In the current analysis the launch vehicle is held in position using a holding / retracting mechanism and at a predefined time the vehicle is released. The boundary condition required a novel
Kurudimath, Kottresh MaharudraiahJalan, SalilRose, Jancy
Launch vehicle structures are designed to withstand flight loads while fulfilling their intended functional requirements. Most of these structures use cylindrical geometries and employ stiffened configurations—such as isogrid, orthogrid, or skin-stiffened designs—comprising multiple long panels to efficiently carry dominant compressive loads. Traditional FE analyses generally use simplified or idealized imperfection models, which often do not represent the imperfections present in actual hardware and therefore tend to over/under-predict load-carrying capacity based on the initial assumed imperfection level. In reality, long stiffened panels are highly sensitive to geometric imperfections introduced during manufacturing. These include spring-back effects from roll bending as well as deviations accumulated during assembly. Such manufacturing-induced variations can significantly diminish the effective load-bearing capability of the structure. The subject hardware—an isogrid cylindrical
Sharma, AmitSingh, NishantXavier, ShijoR, Suresh
High Cycle Fatigue (HCF) is a critical failure mode in turbofan blades, primarily driven by resonance phenomena when the blade’s natural frequency aligns with engine-induced excitations. Traditional approaches to mitigate HCF often involve geometric modifications or damping treatments, which can adversely affect aerodynamic performance or increase component weight. This study explores alternative methodologies to strategically alter the natural frequency of turbofan blades while maintaining aerodynamic efficiency and structural integrity. A novel material architecture is proposed, consisting of a dual-metallic configuration with a high-stiffness core and a lightweight, fatigue-resistant outer shell. This design enables precise tuning of the blade’s dynamic response by leveraging the contrasting mechanical properties of the core and outer materials. The dual-metallic structure shifts the natural frequency away from critical excitation zones, thereby reducing the risk of resonance
S, RavivarmanInamdar, PrachiDe, Rohit
Dynamic characterization tests play a critical role in launch vehicle applications, as they provide the frequencies and mode shapes required for refining Finite Element Models (FEM) and ensuring structural integrity. While such tests are often routine when mode shapes in orthogonal planes are well separated, practical challenges arise when modes are closely spaced. In these cases, careful test planning and execution become essential to obtain reliable results. A key factor influencing test outcomes is the boundary condition of the test article. Although free-free suspension, achieved through very low-frequency support, is theoretically ideal, it is often impractical. As a result, most dynamic characterization tests are performed with a base-fixed condition, where the properties of the supporting structure can influence the measured response. For structures with asymmetry limited to a single axis, mode shapes are typically expected to align along that axis; however, deviations may occur
Panda, Ajay KumarAvirah, Nohin KShaikh, Altafhusen
Predicting the fatigue life of threaded bolts is crucial in aerospace and mechanical assemblies where cyclic loading can cause early joint failure. Existing studies, like [1], have created S-N curves for high-strength bolts under different pretension and temperature conditions through experimentation. However, there are few numerical methods that can replicate these results, especially for bolts without pretension. This study develops and validates a finite element analysis (FEA) methodology to predict the fatigue performance of pretensioned threaded bolts under axial loading, using the experimentally derived Series-2 S-N data for M20 high-strength bolts with pretension. The approach employs a detailed 3D solid model with explicit thread geometry and a two-step transient structural analysis. This first simulates the bolt tightening process to establish a realistic preload, followed by the application of a service tensile load. Local stress distributions are analyzed to extract peak
K R, LesanthS, Suhail AhmedC, ArunvetrivelP, KrishnakumarP S, PremkumarVasantharaj, C
This SAE Recommended Practice provides recommended guidelines and best practices for implementing a supportability program to ensure that software is supportable throughout its life cycle. This Implementation Guide is the companion to the Software Supportability Program Standard, SAE JA1004, that describes, within a Plan-Case framework, what software supportability performance requirements are necessary. This document has general applicability to all sectors of industry and commerce and to all types of equipment whose functionality is to some degree implemented via software. It is intended to be guidance for business purposes and should be applied when it provides a value-added basis for the business aspects of development, use, and sustainment of support-critical software. Applicability of specific recommended practices will depend on the support-significance of the software, application domain, and life cycle stage of the software.
G-41 Reliability
The importance of reliability in design engineering has significantly grown since the early 1960’s. Competition has been a primary driver in this growth. The three realities of competition today are: world class quality and reliability, cost-effectiveness, and fast time-to-market. Formerly, companies could effectively compete if they could achieve at least two of these features in their products and product development processes, often at the expense of the third. However, customers today, whether military, aerospace, or commercial, have been sensitized to a higher level of expectation and demand products that are highly reliable, yet affordable. Product development practices are shifting in response to this higher level of expectation. Today, there is seldom time, or necessary resources to extensively test, analyze, and fix to achieve high quality and reliability. It is also true that the rapid growth in technology prevents the accumulation of historical data on the field performance
G-41 Reliability
This document provides methods and techniques for implementing a reliability program throughout the full life cycle of a software product, whether the product is considered as standalone or part of a system. This document is the companion to the Software Reliability Program Standard [JA1002]. The Standard describes the requirements of a software reliability program to define, meet, and demonstrate assurance of software product reliability using a Plan-Case framework and implemented within the context of a system application. This document has general applicability to all sectors of industry and commerce and to all types of equipment whose functionality is to some degree implemented by software components. It is intended to be guidance for business purposes and should be applied when it provides a value-added basis for the business aspects of development, use, and sustainment of software whose reliability is an important performance parameter. Applicability of specific practices will
G-41 Reliability
SAE JA6097 (“Using a System Reliability Model to Optimize Maintenance”) shows how to determine which maintenance to perform on a system when that system requires corrective maintenance to achieve the lowest long-term operating cost. While this document may focus on applications to Jet Engines and Aircraft, this methodology could be applied to nearly any type of system. However, it would be most effective for systems that are tightly integrated, where a failure in any part of the system causes the entire system to go off-line, and the process of accessing a failed component can require additional maintenance on other unrelated components.
HM-1 Integrated Vehicle Health Management Committee
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