Progress in Aerospace Sciences最新文献

Lattice structures, produced by repeated unit cells in the particular pattern, offer a high strength-to-weight ratio. The current advancement in Additive manufacturing (AM) technology, creating complex geometries like lattice structures has revolutionized production across various industries. While several reviews have focused on different specific aspects of lattice structures, a comprehensive overview of recent advancements of lattice in aerospace structural applications is lacking.

Therefore, a comprehensive review of lattice structures used in aerospace lightweight applications manufactured through AM is presented here. Basic classification of lattice structure is presented followed by detailed study of several factors influencing mechanical properties of lattice structures, crucial for aerospace lightweight application. Current trends in manufacturing technologies of lattice structures are analyzed in detail with identification of capabilities and limitations. Furthermore, detailed literature on the lattice structure optimization techniques is presented with current limitations. Furthermore, the engineering applications of lattice structures in aerospace lightweight, along with the fabrication processes involved, challenges in applications of lattice in aerospace applications and future research directions are reported.

By providing insights into current research trends and future directions, this review serves as a valuable resource for researchers and engineers involved in the design and development of lightweight aerospace lattice structures. It lays the groundwork for the exploration of new and innovative lattice structures tailored to meet the evolving needs of the aerospace industry.

the passive safety of aircraft passengers is such an important aspect in the design of aircraft structures as strength and fatigue concerns. The development of methods and devices to prevent passenger injuries is the subject of continuous efforts. The mission is to minimize stresses and accelerations on passengers during a crash. Over the years, studies on crash phenomena have been focused on experimental tests, using full-scale structures and Anthropomorphic Test Devices (ATDs) to assess the consequences of impact phenomena on the human body. However, due to the high costs of experimental campaigns and the difficulty of controlling all relevant parameters, the need of efficient numerical models capable of validating experimental data has increased. This is specifically relevant for tests on ATDs.

In the frame of this work, the side-impact of an aircraft passenger have been numerically investigated positioned on a window-side seat of an aluminium commercial aircraft fuselage a World SID-based dummy. An attempt to increase the aircraft crashworthiness was made placing in correspondence with the head and the shoulders of the dummy hybrid sandwich shock absorbers. In order to validate the considered dummy model, a lateral impact against a flat barrier has been carried out. The obtained numerical results have been cross-compared with literature experimental data. Then, the side-impact behaviour of the dummy within a fuselage section has been investigated, with the aim to verify the absorption capability of the shock absorbers and to quantify their effect on the safety of the dummy. The employment of the shock absorbers allowed to reduce the acceleration peaks experienced by the dummy's head up to 50%.

Airplanes are inevitably subjected to various impact loading conditions in the event of emergency landing. An airplane crash scenario is a complex nonlinear impact event which involves large deformation, material fracture, structural failure, and dynamic contact. The impact response becomes more complicated due to the presence of composite materials, which are becoming the dominated choice for aircraft components. However, the impact damage and failure severity of composite fuselage sections can be effectively alleviated with optimized energy absorbing (EA) design. Accordingly, the crashworthy design of fuselage sections has always remained a top priority to prevent catastrophic structural failure and significant casualties. This paper presents a systematic literature review on the impact response and EA design of composite fuselage structures. Firstly, the typical composite materials such as composite tubes, corrugated composite plates, hybrid composite structures and bio-inspired composite materials are introduced to dissipate the impact kinetic energy during a crash. Then, the analytical models and finite element modeling methods of composite bolted joint structures are described to investigate their impact response and failure mode. The crashworthy design of typical composite fuselage structures including sub-cargo support struts, cabin floor support struts, fuselage frame and cabin floor/fuselage frame connection are described in this paper. Finally, an emphasis is placed on the evaluation criteria of the occupant crash safety and the crashworthy evaluation method of fuselage structures.

Crashworthiness is the ability of civil aircraft fuselage structure and internal systems to maximum protect the occupants’ safety in a crash or emergency landing event, and is an important embodiment of the civil aircraft safety, which can determine the occupant survivability to a certain extent. The crashworthiness is dominated by the crash response characteristics of typical fuselage section (including occupant/seat restraint system), and the crashworthiness evaluation mainly includes fuselage structural response evaluation and occupant injury evaluation. Firstly, the crashworthiness requirements are sorted out according to the Airworthiness Standards of transport category airplanes and Special Conditions, and the research work on drop tests and crashworthiness numerical simulation of fuselage section are gathered. Then, the failure of typical skin-stringer-frame structures and fuselage section are analyzed, and the crash safety evaluation criteria are summarized. After that, the impact tolerance of various parts of human (head, neck, thoracic, spine, abdomen, extremity) and the occupant injury evaluation criteria are summarized. In addition, the crashworthiness design principles and design methods of fuselage section are outlined for occupant survivability. Finally, the crashworthiness evaluation under different crash factors and conditions (impact velocity, impact ground, cargo loading and aircraft wing position) are summed up, and the aircraft crashworthiness is comprehensively evaluated through integrating the survivable volume, the retention strength, the occupant injury and the emergency evacuation, and the crashworthiness evaluation process is outlined. This article is intended as a comprehensive literature review of crashworthiness design and evaluation of fuselage structure for occupant survivability.

The crashworthiness of a structure is a measure of its protective capability under dynamic events by absorbing the crash energy in a controlled way. Fiber reinforced composite materials can represent a valid alternative to ductile metals as impact energy absorbers in a crashworthy structure. In fact, composites are characterized by high mechanical properties coupled with low weight, capability to be designed by tailoring the specific requirements and good energy absorption capabilities. However, the impact resistance and the damage modes of long fiber composites involve different factors (constituent materials, geometry, lay up, manufacturing process) and are difficult to predict. In addition, there are no standard experimental procedures to assess the crashworthiness of composite materials. Therefore, a large and proper experimental characterization on composites with different geometries can be useful to understand the failure mechanisms under dynamic loads.

In this work, three different kinds of carbon fiber epoxy composites have been realized by vacuum infusion process in order to investigate the effect of the width and the shape. In particular, two plane and one C-shaped composites have been manufactured and characterized with Charpy test at different impact velocity according to the three-point bending procedure. Further, in-plane compression tests on larger flat composites have been performed by using an anti-buckling fixture to evaluate the specific Energy Absorption (SEA). Results evidenced the effect of the impact velocity on the impact resistance, the greatest rigidity of the c-shaped composite and the damage modes.

One of the most critical air transportation issues is the passengers' protection during collision and impact events that must be absorbed in a controlled way in order to reduce damages. The capability of an aircraft to eliminate injuries in relatively mild impacts and to reduce severe effects on occupants in critical crashes is called crashworthiness. The crashworthiness is the ability of a structure to protect occupants during dynamic events. It is usually measured by the capacity of a structural system to dissipate kinetic impact energy by itself, by means of a controlled and predictable deformation aimed to minimize stresses and accelerations on passengers during a crash. In aeronautical applications, the crashworthiness is dominated by the crash response characteristics of typical fuselage sections (including occupant/seat restraint system), and the crashworthiness evaluation mainly includes fuselage structural response evaluation and occupants’ level of injury evaluation. This special issue consists of four papers, starting with a review of the crashworthiness design and evaluation aspects of civil aircraft fuselage structures, followed by a review of the impact response characteristics and the crashworthy design principles for composite fuselage structures. The third paper addresses the issue of the lack of standard experimental procedures to assess the crashworthiness of composite structures whereas the fourth paper describes a numerical model for the simulation of the side impact of an aircraft passenger.

To ensure the secure operation of space assets, it is crucial to employ ground and/or space-based surveillance sensors to observe a diverse array of anthropogenic space objects (ASOs). This enables the monitoring of abnormal behavior and facilitates the timely identification of potential risks, thereby enabling the provision of continuous and effective Space Situational Awareness (SSA) services. One of the primary challenges in this endeavor lies in optimizing the tasking of surveillance sensors to maximize SSA capabilities. However, the complexity of the space environment, the vast number of ASOs, and the limitations imposed by available sensor resources present significant obstacles to effective sensor management. To tackle these challenges, various sensor tasking methods have been developed over the past few decades. In this paper, we comprehensively outline the fundamental characteristics of sensor tasking missions, and later examine the corresponding objective functions and algorithms employed for efficient optimization, respectively. Furthermore, we explore the practical application of sensor tasking methods in diverse organizations and provide insights into potential directions for future research, aiming to stimulate further advancements in this field.

The Cislunar region is crucial for expanding human presence in space in the forthcoming decades. This paper presents a comprehensive review of recent and anticipated Earth–Moon missions, and ongoing space domain awareness initiatives. An introduction to the dynamics as well as periodic trajectories in the Cislunar realm is presented. Then, a review of modern Cislunar programs as well as smaller missions are compiled to provide insights into the key players pushing towards the Moon. Trends of Cislunar missions and practices are identified, including the identification of regions of interest, such as the South Pole and the Near-rectilinear halo orbit. Finally, a review of the current state and short-comings of space domain awareness (SDA) in the region is included, utilizing the regions of interest as focal points for required improvement. The SDA review is completed through the analysis of the Artemis 1 trajectory.

Concentrated vortex flows contribute to the aerodynamic performance of aircraft at elevated load conditions. For military interests, the vortex flows are exploited at maneuver conditions of combat aircraft and missiles. For transport interests, the vortex flows are exploited at takeoff and landing conditions as well as at select transonic conditions. Aircraft applications of these vortex flows are reviewed with a historical perspective followed by a discussion of the underlying physics of a concentrated vortex flow. A hierarchy of computational fluid dynamics simulation technology is then presented followed by findings from a capability survey for predicting concentrated vortex flows with computational fluid dynamics. Results are focused on military and civil fixed-wing aircraft; only limited results are included for missiles, and rotary-wing applications are not assessed. Opportunities for predictive capability advancement are then reported with comments related to digital transformation interests. A hierarchical approach that merges a physics-based perspective of the concentrated vortex flows with a systems engineering viewpoint of the air vehicle is also used to frame much of the discussion.

The academic community has extensively studied fault management in dynamical and cyber-physical systems, leading to the development of various model-based and data-driven/learning-enabled methods. Although these advanced designs show promise for improving conventional practices in aircraft systems, there is a noticeable disparity between academic methodologies and the specific needs of the aviation industry. The paper begins with an examination of the current practices within the aviation industry alongside the academic state of the art. It highlights commonly overlooked issues that hinder the transition from laboratory development to practical flight applications. Looking ahead, the paper anticipates evolving needs driven by the transition towards greater autonomy and intelligence within connected and distributed cyber-physical flight environments. This includes the emerging trend towards the introduction of Single Pilot Operations (SPO). The paper presents an outline of a combined model-based/data-driven vision, under human oversight, to navigate this complex transition.