Periodic controllers for vibration reduction using actively twisted blades

This paper compares two periodic control methods, the optimal H2 and the periodic static output feedback (POF), to reduce the helicopter rotor vibrations. Actively twisted blades with Macro-Fibre Composite (MFC) piezoelectric actuators are used. The design model is based on a simplified aerodynamic model and on a multi-body model of the Bo 105 isolated rotor with the original blades replaced by actively twisted ones. The performance of the two controllers in alleviating hub loads is verified with improved simulations based on a free-wake model

a review of particle damping modeling and testing

Abstract This survey provides an overview of the different approaches seen in the literature concerning particle damping. The emphasis is on particle dampers used on beams vibrating at frequencies between 10 Hz and 1 kHz. Design examples, analytical formulations, numerical models, and experimental setups for such dampers are gathered. Modeling approaches are presented both for particle interaction and for systems equipped with particle dampers. The consequences of the nonlinear behavior of particle dampers are brought to attention. As such, the apparent contradictions of the conclusions and approaches presented in the literature are highlighted. A list of particle simulation software and their use in the literature is provided. Most importantly, a suggested approach to create a sound numerical simulation of a particle damper and the accompanying experimental tests is given. It consists of setting up a discrete element method simulation, calibrating it with literature data and a representative damper experiment, and testing it outside of the range of operation used for the tuning

A review of friction damping modeling and testing

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Substructuring-based accurate beam section characterization from finite element analysis

The elastic characterization of beam sections is a complex problem, especially for non-homogeneous beams composed of anisotropic materials. Over the past four decades, several viable solutions have been proposed to address this important scientific and engineering challenge. These solutions either require a dedicated formulation for section discretization or, if based on conventional finite element methods, inevitably introduce unnecessary approximations. This work presents a formulation equivalent to well-established approaches available in the literature without requiring dedicated, specialized discretization formulations and techniques. Instead, it utilizes conventional linear finite element analysis to discretize the beam section and the concept of substructuring to analyze a finite chunk of the beam. The formulation is contextualized, described, and verified through examples of increasing complexity and generality, whose results are compared against those available in the open literature

Engineering of a CMC aeronautical muffler

This work explores the feasibility of adopting an LSI produced C/SiC composite to build an aeronautical Auxiliary Power Unit system muffler. The study first covers the experimental material characterization through tensile and compressive tests. The material properties are characterized also after exposing the samples to an oxidizing atmosphere, that is typical for the proposed application. The material response is characterized by significant non-linearities and a pseudo plastic response, which were numerically modeled using a Drucker-Prager model. The detailed design of the muffler is described and verified, for different loading conditions, using a Finite Element model. Finally, a full-scale prototype is produced and assembled, thus proving the technological feasibility of the design. The manufacturing phase required to study and understand the phenomena that were leading to defects in the proposed closed axial symmetric shape, and to implement suitable technological solutions in order to get an acceptable prototype

Physical-Mechanical Properties of Peat Moss (Sphagnum) Insulation Panels with Bio-Based Adhesives

Rising energy and raw material prices, dwindling resources, increased recycling, and the need for sustainable management have led to growth in the smart materials sector. In recent years, the importance and diversity of bio-based adhesives for industrial applications has grown steadily. This article focuses on the production and characterization of insulation panels consisting of peat moss and two bio-based adhesives. The panels were pressed with tannin and animal-based resins and compared to panels bonded with urea formaldehyde. The physical-mechanical properties, namely, thermal conductivity (TC), water vapor diffusion resistance, modulus of rupture (MOR), modulus of elasticity (MOE), internal bond (IB), compression resistance (CR), water absorption (WA) and thickness swelling (TS) were measured and analyzed. The results show that the insulation effectiveness and mechanical stability of moss panels bound with tannin and animal glue are comparable to standard adhesives used in the composite industry.O

Integrating collaborative robots in manufacturing, logistics, and agriculture: Expert perspectives on technical, safety, and human factors

This study investigates the implementation of collaborative robots across three distinct industrial sectors: vehicle assembly, warehouse logistics, and agricultural operations. Through the SESTOSENSO project, an EU-funded initiative, we examined expert perspectives on human-robot collaboration using a mixed-methods approach. Data were collected from 31 technical experts across nine European countries through an online questionnaire combining qualitative assessments of specific use cases and quantitative measures of attitudes, trust, and safety perceptions. Expert opinions across the use cases emphasized three primary concerns: technical impacts of cobot adoption, social and ethical considerations, and safety issues in design and deployment. In vehicle assembly, experts stressed the importance of effective collaboration between cobots and exoskeletons to predict and prevent collisions. For logistics, they highlighted the need for adaptable systems capable of handling various object sizes while maintaining worker safety. In agricultural settings, experts emphasized the importance of developing inherently safe applications that can operate effectively on uneven terrain while reducing workers’ physical strain. Results reveal sector-specific challenges and opportunities: vehicle assembly operations require sophisticated sensor systems for cobot-exoskeleton integration; warehouse logistics demand advanced control systems for large object handling; and agricultural applications need robust navigation systems for uneven terrain. Quantitative findings indicate generally positive attitudes toward cobots, particularly regarding societal benefits, moderate to high levels of trust in cobot capabilities and favorable safety perceptions. The study highlights three key implications: (1) the need for comprehensive safety protocols tailored to each sector’s unique requirements, (2) the importance of user-friendly interfaces and intuitive programming methods for successful cobot integration, and (3) the necessity of addressing workforce transition and skill development concerns. These findings contribute to our understanding of human-robot collaboration in industrial settings and provide practical guidance for organizations implementing collaborative robotics while considering both technological advancement and human-centered design principles

Helicopter Rotor Sailing by Non-Smooth Dynamics Co-Simulation

This paper presents the application of a co-simulation approach for the simulation of frictional contact in general-purpose multibody dynamics to a rotorcraft dynamics problem. The proposed approach is based on the co-simulation of a main problem, which is described and solved as a set of differential algebraic equations, with a subproblem that is characterized by nonsmooth dynamics events and solved using a timestepping technique. The implementation and validation of the formulation is presented. The method is applied to the analysis of the droop and anti-flap contacts of helicopter rotor blades. Simulations focusing on the problem of blade sailing are conducted to understand the behavior and assess the validity of the method. For this purpose, the results obtained using a contact model based on Hertzian reaction forces at the interface are compared with those of the proposed approach

Promoting Behavioural Safety in Gas Manufacturing: Adaptation of the B-safe Training Program

In the industrial gas manufacturing sector, stringent safety protocols and proactive safety promotion are crucial to prevent hazardous incidents protect employees, customers, and the environment from the potential risks of handling and transporting these gases. Train The Trainer (TTT) programmes can be tailored to the organisation’s needs and cover various topics, such as handling hazardous materials, emergency response procedures, equipment use and ergonomics, and managing emergency response procedures. The B-SAFE project, designed based on the ‘Communities of Practice’ theoretical framework and adopting the TTT approach, aims to provide workers with tools and resources to increase work safety and reduce accidents by acting on underlying cognitive behaviour and processes. The present case study aims to present the Italian adaptation of the B-SAFE training programme, incorporating specific revisions resulting from previous research. Twenty-five Health, Safety and Environment (HSE) top and middle managers from a leading gas manufacturing firm participated in the five-module training. At the conclusion of each B-SAFE module, they filled out a short questionnaire to report their satisfaction with the training methods and content. The answers were analysed to gather feedback on the course. In general, participants found the course to be useful, satisfying, fun and easy