Pneumatic Structures Research Articles

Experimental nonlinear response of a new tensairity structure under cyclic loading

Pneumatic structures are recognized as promising thin-walled structures for their advantageous features such as lightness, portability, versatile design, and ease of installation. Although their bearing capacity under monotonic static loads can be formidable, their inherent dissipation capacity is low and thus entails significant limitations when counteracting dynamic loads. A novel tensairity structure is here proposed to overcome this drawback. The innovative design features a cylindrical inflatable element integrated with NiTiNOL cables wrapped around and affixed to a slender beam positioned along its generatrix. A laboratory-scale prototype is employed to assess how the structure behaves under cyclic loading in comparison to a standalone inflated beam and a conventional tensairity structure outfitted with steel cables. This experimental study delves into the influence of internal pressure and pretension levels of the metallic cables. Experimental results unfold a smooth softening-type hysteretic behavior under cyclic loading, which is accompanied by a slight stiffness degradation and a moderate pinching. The comparative analysis of the experimental results also demonstrates the substantially improved and consistent dissipation capacity of the presented novel concept of tensairity structure, which thus offers superior stability under cyclic loads. A parametric identification based on a modified Bouc–Wen model is finally performed to simulate the hysteretic response of the structure. A correlation is also established between the identified parameters of the phenomenological model and the internal pressure, type and cables pretension levels. The excellent agreement between numerical predictions and experimental force–displacement cycles other than those used for the parametric identification demonstrates the suitability of the adopted phenomenological modeling.

An evaluation of the examples of mobile smart agriculture applications in Turkiye

The technological process of agricultural mechanization has evolved from mechanical, hydraulic, and pneumatic structures to electrical-electronic and mechatronic systems. With the addition of digital technologies in recent years, agricultural mechanization tools have had functions as time-independent, non-spatial, and unmanned. Agricultural production technologies are now equipped with integrated systems with the Internet of Things, cloud informatics, image processing, wireless data transmission, and mobile-portable devices. Today, during the production process, physical, biological, or chemical data detected through sensors from plants, animals, soil, and atmosphere are uploaded to computers and cloud informatic technologies as big data sets. The data is presented to decision-makers via mobile devices connected to the internet. Within the scope of this study, examples of mobile-portable applications used in the field of smart agriculture in the world and our country were generally examined. In addition, technological and sectoral applications for mobile smart agriculture in our country have been taken over. Currently, common application examples of the Ministry of Agriculture and Forestry, and some private sector companies, that produce these technologies and provide them for the end users, have also been researched in this context. In addition to these, the strengths and weaknesses of the current portable mobile applications in agricultural production have been tried to be analyzed in terms of our country’s conditions.

Modular Design of Multistable Pneumatic Structures from a Flat Pattern of Air Pouches

We introduce a novel family of structures that can be inflated from a plane to form a three-dimensional surface using articulated straight pouches with inextensible membranes. Specifically, we propose a modular design using a quadrangle surrounded by four slender pouches, whose inflation causes the surface to form a saddle shape. Then we show a fabrication method using heated nylon films with heat adhesives separated by paper mask patterns inside. We first show a geometric model to explain and predict the out-of-plane deformation and the bi-stability effect inherited in this structure. Through a geometric analysis and an elastic simulation of a pouch, we show that lowering the width-length ratio of pouches reduces the imperfection of shapes. We further propose a method for controlling the height of saddles using concentric patterns. We then extend structural modules into multiple-grid systems and identify the multistable behaviors of the overall structure.

Model Proposal for the Use of Pneumatic (Inflatable) Structures in the Case of Earthquake Disaster

Earthquake is natural disaster that can cause great destruction and loss of life and property. Temporary emergency structures, tents or containers, are used continuously until the reconstruction of the basic needs after the earthquake disaster. However today, with innovative structures, various systems that can offer more advantageous solutions to the needs of disaster victims can be proposed. In this study, the use of pneumatic (inflatable) structures for earthquake disasters is discussed. Since it is system that relatively little known and has wide variety of structural features, it is aimed to develop holistic fictional model that includes the process for making the most appropriate selection. Thus, as a result of the introduction of pneumatic structures and the creation of model for use; will be widespread by increasing the awareness of its positive qualities such as lightness, fast construction, easy storage in small volumes and transportation, flexibility and reusability in earthquake disasters.

Inflatable architecture. Short critical history of uses in architecture

The pandemic crisis, as a turning point in recent history, has caused existing resources to be mobilized in a short time and triggered the emergence of unique approaches to spatial reorganization. With their formal freedom, unlimited adaptability and short production cycle times, lightweight inflatable or pneumatic structures, which are still in the midst of a technological boom, are an undeniable source of inspiration for today's crisis adaptation. Beyond pragmatic features such as ergonomics, protection and cleanliness, a variety of stylistic approaches can be identified, ranging from small-scale, minimal interventions in interior architecture, to large-scale, urban interventions. The article reviews the sources of inspiration that cross time and space, moving from the utopias of the 1960s to the emergency projects of the 21st century, with the aim of highlighting, through the broad spectrum of solutions, a direction to follow in architecture adapted to crisis solutions. Inflatable structures still fascinate, having the potential to be symbolic in any context.

Re-assessment of the Late Jurassic eusauropod Mamenchisaurus sinocanadorum Russell and Zheng, 1993, and the evolution of exceptionally long necks in mamenchisaurids

The sauropod genus Mamenchisaurus, from the Late Jurassic–Early Cretaceous of East Asia, has a convoluted taxonomic history. Although included in the first cladistic analysis of sauropods, only recently has the monophyly of Mamenchisaurus, and the anatomical diversity of the many penecontemporaneous East Asian eusauropods, been evaluated critically. Here, we re-describe the holotype and only specimen of M. sinocanadorum. Although the original diagnosis is no longer adequate, we identify several autapomorphies that support the validity of this species, including an elongate external mandibular fenestra and distinctive pneumatic structures on the cervical centra. We incorporate new data into a phylogenetic character matrix that also includes Bellusaurus and Daanosaurus, both of which are known only from juvenile material and are often hypothesized to be neosauropods (or close relatives thereof). We recover all species of Mamenchisaurus as part of a radiation of predominantly Middle–Late Jurassic East Asian eusauropods, but the genus is non-monophyletic, underscoring the need for further systematic revision of mamenchisaurid taxonomy. Analyses that score ontogenetically variable characters ambiguously recover Bellusaurus and Daanosaurus as juvenile mamenchisaurids, a hypothesis supported by several features that are unique to mamenchisaurids or exhibit little homoplasy, including anteriorly bifurcate cervical ribs. Finally, computed-tomography reveals extensive vertebral pneumaticity in M. sinocanadorum that is comparable to that of the largest sauropods, and updated scaling analyses imply a neck over 14 m long, rivalling estimates for other exceptionally long-necked sauropods. Previous work has suggested that the elongated cervical ribs of particularly long-necked sauropods such as M. sinocanadorum stabilized the neck by limiting its mobility. Given that extent of pneumaticity responds dynamically to a bone’s habitual loading, we propose that long cervical ribs – and other structural modifications that limited flexibility – promoted the evolution of increasingly long necks by producing a more predictable biomechanical milieu amenable to increased pneumatization.

The absence of an invasive air sac system in the earliest dinosaurs suggests multiple origins of vertebral pneumaticity

The origin of the air sac system present in birds has been an enigma for decades. Skeletal pneumaticity related to an air sac system is present in both derived non-avian dinosaurs and pterosaurs. But the question remained open whether this was a shared trait present in the common avemetatarsalian ancestor. We analyzed three taxa from the Late Triassic of South Brazil, which are some of the oldest representatives of this clade (233.23 ± 0.73Ma), including two sauropodomorphs and one herrerasaurid. All three taxa present shallow lateral fossae in the centra of their presacral vertebrae. Foramina are present in many of the fossae but at diminutive sizes consistent with neurovascular rather than pneumatic origin. Micro-tomography reveals a chaotic architecture of dense apneumatic bone tissue in all three taxa. The early sauropodomorphs showed more complex vascularity, which possibly served as the framework for the future camerate and camellate pneumatic structures of more derived saurischians. Finally, the evidence of the absence of postcranial skeletal pneumaticity in the oldest dinosaurs contradicts the homology hypothesis for an invasive diverticula system and suggests that this trait evolved independently at least 3times in pterosaurs, theropods, and sauropodomorphs.

Principles for the Design of Architectural Objects based on Air-Supported Structures in Extreme Conditions: the Example of the Covid-19 Epidemic

The article is devoted to identifying the current principles of designing architectural objects based on pneumatic air-supported structures in extreme conditions using the example of the Covid-19 pandemic. The object of the research is project proposals and realized pneumatic buildings and structures of the XXI century, created during the period of the Covid-19 epidemic. The objective of the study is to identify the basic principles for improving the design concepts of pneumatic air-supported objects in a pandemic and post-pandemic period in the context of international architectural and engineering trends to predict the vector of their further development. The methodological approach to the study of these problems is based on a systematic analysis of the features of the formation of pneumatic structures and is based on the materials of the implemented and designed buildings and structures of pneumatic architecture, as well as the study of open domestic and foreign scientific publications in this area. The findings of the study demonstrate the key advantages of using pneumatic air-supported structures in the creation of architectural buildings and structures based on the identified design principles, considering modern measures of epidemiological safety. The results obtained can be useful for architects, designers and engineers.

Form Finding of a Single-layered Pneumatic Membrane Structures by Using Nonlinear Force Method

Form Finding of a Single-layered Pneumatic Membrane Structures by Using Nonlinear Force Method

Exquisite air sac histological traces in a hyperpneumatized nanoid sauropod dinosaur from South America

This study reports the occurrence of pneumosteum (osteohistological structure related to an avian-like air sac system) in a nanoid (5.7-m-long) saltasaurid titanosaur from Upper Cretaceous Brazil. We corroborate the hypothesis of the presence of an air sac system in titanosaurians based upon vertebral features identified through external observation and computed tomography. This is the fifth non-avian dinosaur taxon in which histological traces of air sacs have been found. We provided a detailed description of pneumatic structures from external osteology and CT scan data as a parameter for comparison with other taxa. The camellate pattern found in the vertebral centrum (ce) of this taxon and other titanosaurs shows distinct architectures. This might indicate whether cervical or lung diverticula pneumatized different elements. A cotylar internal plate of bone tissue sustains radial camellae (rad) in a condition similar to Alamosaurus and Saltasaurus. Moreover, circumferential chambers (cc) near the cotyle might be an example of convergence between diplodocoids and titanosaurs. Finally, we also register for the first time pneumatic foramina (fo) and fossae connecting camellate structures inside the neural canal in Titanosauria and the second published case in non-avian dinosaurs. The extreme pneumaticity observed in this nanoid titanosaur contrasts with previous assumptions that this feature correlates with the evolution of gigantic sizes in sauropodomorphs. This study reinforces that even small-bodied sauropod clades could present a hyperpneumatized postcranial skeleton, a character inherited from their large-bodied ancestors.

New Shunosaurus (Dinosauria: Sauropoda) material from the middle Jurassic lower Shaximiao Formation of Yunyang, Chongqing, China

ABSTRACT Shunosaurus is a small eusauropod from China. It is characterised by solid cervical and dorsal vertebral centra without complicated pneumatic structures, platycoelous or amphicoelous middle and posterior vertebrae and a lack of pubic foramen in adult individuals. Although many Shunosaurus individuals have been discovered, the ontogenetic characteristics of its long bones and bone tissues are not very clear and the existing description of the postcranial skeleton is relatively rudimentary. The new well-preserved and the smallest Shunosaurus specimen discovered in Yunyang, Chongqing, China, provides good material for solving these problems. The radial distal breadth is more than twice the minimum midshaft breadth, and the fibular distal end is twice as wide as the midshaft, while these ratios are all smaller in adult specimens. The lateral trochanter is undeveloped. This individual does show a pubic foramen. The degree of vascularisation of the bone tissue in the juvenile bone tissue is higher for adults. There are no arrested growth lines and peripheral rest lines in the compact bone, indicating that body size still increases slowly after maturity. The discovery of this new material expands the distribution range of Shunosaurus in China.

Flat pneumatic elements and their potential use in the construction of dwelling facilities within emergency housing systems

As part of this study, experimental and theoretical investigations into the strength and stiffness of flat pneumatic elements to be used in lightweight dwelling structures, enabling the quick assembly of the latter, were undertaken.
 On the basis of the experimentally and theoretically determined parameters of the elements it will be possible to design configurations of spatial pneumatic structures.
 In particular, the following were devised and carried out:
 
 a theoretical assessment of the load capacity and stiffness of selected pneumatic elements depending on their dimensions, internal pressure and fixing and support conditions,
 an experimental verification of the obtained results.
 
 This study has an exploratory character and constitutes the basis for the design and implementation of original technical, constructional and architectural solutions relating to the application of spatial pneumatic structures in the emergency system.
 It should be mentioned that in the known literature on the subject there is no theoretical basis for designing structures whose principal member is a flat pneumatic element.
 In the construction industry such structures have not been used so far. An exemplary solution of the spatial dwelling structure has been patented under the name Obiekt mieszkalny (Dwelling facility), (patent no. 131 528, of 18.04.1988).

Comprehensive study on mechanical properties of coated biaxial warp-knitted fabrics

In recent years, coated fabrics have become the major material used in membrane structures. Due to the special structure of base layer and mechanical properties, coated biaxial warp-knitted fabrics are increasingly applied in pneumatic structures. In this article, the mechanical properties of coated biaxial warp-knitted fabrics are investigated comprehensively. First, off-axial tensile tests are carried out in seven in-plane directions: 0°, 15°, 30°, 45°, 60°, 75°, and 90°. Based on the stress–strain relationship, tensile strengths are obtained and failure modes are studied. The adaptability of Tsai–Hill criterion is analyzed. Then, the uniaxial tensile creep test is performed under 24-h sustained load and the creep elongation is calculated. Besides, tearing strengths in warp and weft directions are obtained by tearing tests. Finally, the biaxial tensile tests under five different load ratios of 1:1, 2:1, 1:2, 1:0, and 0:1 are carried out, and the elastic constants and Poisson’s ratio are calculated using the least squares method based on linear orthotropic assumption. Moreover, biaxial specimens under four load ratios of 3:1, 1:3, 5:1, and 1:5 are further tensile tested to verify the adaptability of linear orthotropic model. These experimental data offer a deeper and comprehensive understanding of mechanical properties of coated biaxial warp-knitted fabrics and could be conveniently adopted in structural design.

Possibilities of Architectural and Structural Forming of Spatial Forms from Rod Arches

The process of forming new technological methods of construction of buildings and structures, a high degree of industrialization of construction and unification of elements, lead to the study of various principles of forming the spatial structure of the object from flat scans. The authors consider a new transformable architectural and structural system consisting of rod spatial arches, the main elements of the developed system are rods and hinges that connect them at the ends. The latter are made as an analog of bionic mobile communication. Analysis of the transformation of a rod spatial element into an arch of various shapes is performed by the following methods: traverses, jacks, pneumatic structures and automatic methods. As a result, you can use rod arches to create buildings and structures of various shapes. In the end, the versatility of such spaces allows buildings and structures based on rod spatial arches to be multifunctional. Specifically for the arches of the NPI series, the authors developed a hinge Assembly designed to connect the rods of a fast-erecting light spatial structure of a regular structure. Research has shown that on the basis of the resulting arched strezhnevoy system, it is possible to form spaces close to the cylindrical and spherical shape. The variability of forms based on a single set of structures, low-labor-intensive installation process using the principles of self-construction, create prerequisites for new research in the field of improving this type of transformable architectural and structural systems. These issues provide a wide range of tools for solving architectural, structural and technological factors of shaping, which contributes to the development of creative activity.

A simple finite element framework for modelling pneumatic structures

Besides material and geometric stiffness, usual components affecting tension structures in general, pneumatic structures are endowed with a pneumatic stiffness, which corresponds to a reluctance of the pressure envelope to change its volume. The higher the inside pressure, the more relevant this component can be. Researches on the nonlinear behavior of pneumatic structures usually consider finite strains, which might indeed be necessary to analyze highly pressurized system. Most civil and architectural applications, however, are subject to low to moderate pressures, with materials undergoing small strains, for which simplified material models may suffice, provided that a sound model to cope with membrane wrinkling is also considered.This paper presents a simple yet effective model to cope with the nonlinear analysis of pneumatic membranes under wind loads, incorporating an effective wrinkling criterion into Argyris’ membrane element, and deriving new expressions for its pneumatic stiffness. The model was tested through an inexpensive experiment, comprising the compression of an exercise ball, which corroborated the importance of considering variable inside pressures, for moderate-pressure systems. This relevance reduces, however, as the dimensions of the structures increase, especially in the case of large insufflated domes.

The Impact of using the Pneumatic Structures on the Sustainability of Iraqi Cities During Religious Events

Pneumatic structures are recyclable structures characterized by adaptability and flexibility. They are an excellent solution for designing structures intended for quick or temporary gatherings. Pneumatic structures are used for sporting, entertainment, military and other events. It is also distinguished by its light weight, ease of installation and disassembly. Also, some cities in Iraq suffer from excessive randomness during religious occasions as a result of creating places of gathering and overnighting in irregular ways and using heavy construction materials that sometimes need digging. This affects the aesthetics of the city and damages the infrastructure. Therefore, the importance of the current research lies in the intent of improving the gathering environment, sustainability of cities, and their appearance during those occasions through the use of pneumatic structures. The study addresses the concept of pneumatic structures and the most important types used to create temporary gathering and accommodation places, in a consistent manner with the nature of the occasion and the environment of Iraqi cities during pilgrimages.

Soft robotic fabric design, fabrication, and thermoregulation evaluation

Usually, traditional insulation materials have a constant thermal resistance value that cannot change within the ambient temperature and will decrease as ambient humidity or external stress increases. Humans heavily rely on heating, ventilation, and air conditioning (HVAC) systems to meet the thermal comfort requirements of their bodies, giving rise to energy waste and global warming. As an infinitely available natural resource, air is one of the most efficient thermal retaining substances known to science. Inspired by soft pneumatic robotics, we propose an architecture for air-driven thermoregulation fabrics called soft robotic fabrics (SRF). By changing the thickness of trapped air layer in fabric system through SRF, wearers could modify garments’ thermal insulation performance. A fabrication method is introduced to rapidly manufacture low-cost pneumatic structures using various types of construction and dimensions. With excellent ductility, elasticity, and compression resistance, the thickness of SRF increases by 12 times or more after inflation, and the fabric even can lift an object 270 times heavier than its weight. The excellent deformability can effectively increase stable air layer between clothing and skin. Based on the Predicted Mean Vote–Predicted Percentage of Dissatisfied model, the thermoregulation capability of SRF helps HVAC expand the temperature setpoint range by 3–8 times when compared with traditional fabrics, and has far-reaching significance in saving energy.

Osteology of Klamelisaurus gobiensis (Dinosauria, Eusauropoda) and the evolutionary history of Middle–Late Jurassic Chinese sauropods

Fossil-rich deposits from the Middle and Late Jurassic of China have yielded a diverse array of sauropod dinosaurs, including numerous species referred to Mamenchisaurus and Omeisaurus. Despite an abundance of fossils and a proliferation of taxa, the anatomy of Middle–Late Jurassic Chinese sauropods remains poorly documented. Here, we comprehensively redescribe and illustrate Klamelisaurus gobiensis from the Middle–Late Jurassic Shishugou Formation of northwest China. Phylogenetic analyses conducted under parsimony and time-calibrated Bayesian optimality criteria consistently recover Klamelisaurus as a member of a predominantly Chinese radiation of exceptionally long-necked eusauropods that includes Mamenchisaurus spp., Chuanjiesaurus, Qijianglong and Wamweracaudia. In most analyses, this lineage also includes Euhelopus, reviving a ‘traditional’ Euhelopodidae and calling into question the macronarian affinities of Euhelopus. Klamelisaurus shares several features with Euhelopus that are unique to a subset of East Asian taxa or rare among sauropods, including a convex ventral margin of the prezygodiapophyseal lamina in middle–posterior cervical vertebrae, a ventrally bifurcated postzygodiapophyseal lamina in posterior cervical vertebrae, and development of a rugose projection extending anteriorly from the epipophysis into the spinodiapophyseal fossa in most cervical vertebrae. Anatomical comparisons of the cervical vertebrae of Klamelisaurus to several other sauropodomorphs and insights from myological studies of extant archosaurs strongly suggest that this latter structure, often considered part of an epipophyseal-prezygapophyseal lamina, is an epaxial muscle scar that is distinct from pneumatic structures of the lateral surface of the neural spine. The phylogenetic and comparative anatomical data presented here provide a foundation for future revision of the taxonomy and systematics of sauropods from the Junggar and Sichuan basins.

Разработка транспортного дирижабля для доставки негабаритных грузов на космодром «Восточный»

An overview of existing methods of delivering oversized cargo using water, rail, road, air and airship transport, an analysis of the world experience in creating lighter-than-air aircraft and identified the most urgent tasks for this type of vehicles in the field of rocket and space technology, in particular, transportation of oversized elements of super-heavy launch vehicles from manufacturers to the Vostochny cosmodrome, search and rescue of astronauts, evacuation of spent stages from fall fields to disposal points and transportation of oversized trusses. The goals and objectives of this work are defined: review of existing projects of transport airships and study of their designs, development of the layout of a transport airship for delivering stages of superheavy launch vehicles from manufacturers to the Vostochny cosmodrome, calculation of the characteristics of the main systems and detailing the design of the vehicle. As exceptional design solutions, we tested the power scheme of gas shells based on supercharged spiral pneumatic structures that allow you to thermostat the carrier gas and fold the shell for storage, as well as a tangential system for blowing the aerodynamic shell, which allows you to reduce the drag of the device. Based on the developed layout, a simplified mathematical model of the device was created, which allows determining the optimal design parameters. These parameters were used for detailed development of each of the systems, then iterative calculation was performed. As a result, the design of a transport airship for the delivery of oversized elements from manufacturers to the Vostochny cosmodrome was developed and its main technical parameters were determined: load capacity-100 tons, cruising speed-126 km / h, flight range-10 thousand km.

Air-imperviousness of reinforced concrete floating caisson type pneumo-structure

This paper gives a brief description of a new type of floating caisson, structure, applicable in hydrotechnical construction of facilities subjected to heavy loadings in water areas, practically by every kind of a baseplate in shallow and deep water. The caisson has a prismatic or cylindrical form and no bottom. It is di­vided in vertical chambers and is provided with top plate (cover). The cai­sson is transported in a floating condition to the lay place. It is possible to introduce slight corrections of the caisson trim and its exact laying on a particular place by varying the air pressure in the chambers. One of the most important things in the construction and operation of concrete-type pneumatic structures is to provide air- imperviousness of the structure for air pressure values up to 2 bar (0.2 MPa). It is believed that the reinforced concrete walls and slabs, properly executed and vibrated, are air-tight even without plaster on them. Nevertheless, the prescribed requirements for the insulation and the provision of airtightness of reinforced concrete must be fully met in combination with varying outside temperature and the constant impact of aggressive seawater.