Air-supported Membrane Structure Research Articles

Study on fire temperature fields of air-supported membrane structures considering thermal–fluid–solid coupling and boundary correction

The study analyzed and compared the effects of thermal–fluid–solid coupling dynamic boundary conditions and traditional fixed-boundary conditions on the distribution of the temperature field under fires. The feasibility of simulating the temperature field distribution was confirmed by using thermal–fluid–solid coupling dynamic boundary conditions. Then, the traditional temperature field analysis methods were corrected by including a flow-based heat exchange coefficient, and the feasibility of this approach was also confirmed. The fire temperature field in a rectangular air-supported membrane structure was analyzed through parameterization. The fire temperature field model of the air-supported membrane structure was established using temperature field data fitting. Furthermore, the study explored the high-temperature material properties of P-type membranes and analyzed and compared the temperature field of the air-supported membrane structure with time-varying mechanical properties of the membrane material to that without time-varying properties.

Thermal-mechanical coupling analysis of membrane surface failure of the air-supported membrane structure under fire considering weld seams

The membrane surface failure by developing a tear in air-supported membrane structures under fire conditions affects the deflation and collapse of the structure. However, in most existing studies, the failure is evaluated only according to whether the membrane surface temperature reaches the burn-through temperature of the membrane materials, without considering the effect of internal pressure variation caused by fire, and there have been even few studies on the impact of weld seams on membrane surface. This paper introduces the simplified constitutive models for PVC membranes and weld seams and a numerical simulation method to analyze the stress on the membrane surface of air-supported membrane structures during fire, taking into consideration the coupling effect of high temperature and internal pressure change. Numerical responses and the results of the full-scale fire test case by HIT (Harbin Institute of Technology) team are compared to demonstrate the effectiveness and applicability of the proposed material models and the simulation method. The study shows that the weld seams are the weak parts of the membrane surface under fire. The membrane surface failure may not first occur at the maximum temperature point of the membrane surface and the initial failure temperature is much less than the burn-through temperature of the membrane materials. Moreover, the initial failure of membrane surface should be attributed to the coevolutionary results of the stress field on the membrane surface and the degraded material properties at elevated temperatures. If the temperature is the only index to determine membrane surface failure in the air-supported membrane structure under fire, the common reference failure temperature should be reduced (approximately 120 ℃ for weld seams and 140 ℃ for membranes). The present study is valuable for fire risk assessment, performance-based fire protection design, and coupled analysis of fire and wind disasters in membrane structures.

Interference effects on the wind loads and wind-induced responses of parallel-arranged rectangular-planed air-supported membrane structures

In many practical projects, two air-supported membrane structures are parallel-arranged. The interference effects of parallel-arranged rectangular-planed air-supported membrane structures are important in the wind-resistant design. In order to address this issue, the wind pressures on isolated and parallel-arranged structures are obtained through pressure measurement wind tunnel tests. The wind-induced responses are calculated via nonlinear dynamic time–history analysis. Consequently, the interference effects on wind loads and wind-induced responses are analyzed. The results show that the wind suctions of downstream structures are amplified by the interferences of parallel-arranged structures particularly under oblique wind directions. The mean wind loads on the most disturbed zone are amplified up to about 65 %. The interference characteristics of wind-induced displacement are basically similar to mean wind loads. The membrane stresses and cable forces are significantly interfered only in oblique wind directions, which are amplified up to about 15 % in all zones of downstream structures. The strongest interference effects can be observed with a spacing-span ratio of 0.2 when the wind direction is oblique or parallel to the gap between neighboring structures. The interference factors for zones are provided to analyze the interference characteristics. In addition, recommendation values of the overall response interference factors are summarized for design reference. The overall response interference factors for displacement, membrane stress, and cable force should be considered as 1.21, 1.33, and 1.20, respectively.

Development of membrane structures in China

This paper presents the development of membrane structures in China. It begins with a historical review of the early applications of membrane structures in the country, highlighting pivotal events and engineering endeavors that contributed to the development. Subsequently, recent advancements in the realm of membrane structures in China are succinctly summarized. The past decade has witnessed notable progress in the implementation of membrane structures, particularly within expansive stadiums and indoor sports arenas. Additionally, cases exemplifying the diverse applications of membrane structures in various projects are presented. Noteworthy among these are the incorporation of membrane structures in building facades, suspended ceilings for indoor spaces, and the utilization of ETFT membrane structures. Furthermore, applications of air-supported membrane structures are explored, especially in the areas of sports facilities and environmental protections. Technical standards and specifications that have played an important guiding role in the development of membrane structures in China are introduced in the last. Finally, 8 issues for the future research and development of membrane structures are pointed out in the conclusion part. It is expected that this paper can serve as a catalyst for further advancement and practical implementation of membrane structures in China.

Analysis on aeroelastic stability of rectangular-planed air-supported membrane structures

This research investigates aeroelastic stability of rectangular-planed air-supported membrane structures subjected to wind actions. By employing potential theory to tackle air flows, the relations between extra aerodynamic forces and structural motions are resolved through the utilization of the boundary element method and the finite element method, capturing the complexities associated with structural geometries and wind pressure distributions. By combining these extra aerodynamic forces with structural dynamic equilibrium equations, critical instability wind velocities for various structural vibration modes are derived. The simulation results are validated through aeroelastic wind tunnel tests, demonstrating a close alignment between the numerical findings and experimental observations in terms of the critical wind velocity and the corresponding instability mode. Additionally, the study analyzes influences of structural geometric configurations, internal pressures, and membrane tensile stiffness on the critical instability wind velocities and corresponding instability modes. It is observed that lower aspect ratios, smaller structural spans, higher internal pressures, and greater membrane tensile stiffness can increase the critical instability wind velocity, corresponding to variations in critical instability mode shapes. Results obtained from this research are expected to provide guidance for the development of wind-resistant designs for air-supported membrane structures.

Fire test study of full-scale air-supported membrane structure in large space

The fire safety issue has been a potential hazard in the rapid development of air-supported membrane structures. Therefore, to obtain the fire response of the air-supported membrane structure, the full-scale fire test of the air-supported membrane structure was designed and carried out, and the fire damage mode was discussed. The fire damage characteristics of the air-supported membrane structure are concluded by analyzing the firepower, air temperature, internal air pressure, and structural deformation. The test results show that the fire’s synergistic effect of high temperature and high air pressure makes welded seams damaged earlier than the membrane. Moreover, damaged parts and opening doors of the structure lead to air leakage. When the air leakage exceeds the air intake, the internal air pressure will drop rapidly, causing the structure to collapse. The collapse at the emergency exit is faster than the structural roof, significantly reducing the available time for safe evacuation.

Aeroelastic wind tunnel investigations on rectangular-planed air-supported membrane structures

This study implements aeroelastic wind tunnel experiments on rectangular-planed air-supported membrane structures. With the goal of identifying possible wind response patterns, experiments are conducted with a wide range of wind velocities, internal pressures, and membrane tensile stiffness, including cases close to similarity requirements for simulating prototypes. Wind pressure measurements on the rigid model are performed to serve as a reference, and during subsequent aeroelastic wind tunnel tests, time-averaged and fluctuating wind responses of air-supported membrane structures are observed to significantly increase with lower internal pressures, higher wind speeds, more incoming turbulence, and less membrane tensile stiffness. Two distinct patterns of wind response, buffeting, and aeroelastic instability, are observed within the aeroelastic wind tunnel experiments. These two patterns exhibit significant differences in terms of fluid–structure interaction mechanisms and statistics of structural wind responses. This research emphasizes the influences of membrane elasticity and incoming turbulence on variations of structural wind response patterns. Aeroelastic instability is observed on models with extreme flexibility and relatively lower incoming turbulence, while the buffeting pattern is observed with other configurations, including cases that approach the similarity requirements for simulating air-supported membrane structures in practice.

Establishment of a Thermal Comfort Model for Spectator Areas of Air-Supported Membrane Ice Rinks in Severe Cold Regions: A Case Study in Harbin, China

In China, the post-Winter Olympics era has seen the rapid development and promotion of ice rinks with air-supported membrane structures. With the rise of large indoor spectator areas in ice rinks, thermal comfort needs in spectator areas are receiving more and more attention. The satisfaction of thermal comfort needs is crucial to people’s health and well-being, so further study of the issue of thermal comfort in such spectator areas is needed. Unfortunately, models currently used to evaluate the thermal comfort of traditional building envelopes are not applicable to air-supported membrane-envelope ice rinks. Researchers need to focus on the internal thermal comfort needs of air-supported membrane envelopes for spectator areas. The aim of this research was to establish a thermal comfort model to provide exact temperature-range recommendations for spectator areas in air-supported membrane ice rinks. The indoor thermal-environment parameters of the ice rink in Harbin were measured from 2 January to 15 January 2023. To elicit data on spectators’ actual thermal sensations in the ice rink, a field questionnaire was administered. By modifying the expectancy factor, an extended predicted thermal comfort model was established. The results suggested that the operative temperature required to meet spectators’ thermal comfort needs in the case study ice rink ranged from 17 °C to 26 °C. The results of the study offer specific insights into the indoor thermal comfort needs of air-supported ice rinks and provide a more accurate temperature-setting reference for the healthy and energy-efficient development of such rinks.

Influence of Friction Coefficient between Cable and Membrane on Wind-Induced Response of Air-Supported Membrane Structures with Oblique Cable Net

Cable-membrane constructions typically exhibit significant displacement and distortion under load action, and the cable-membrane contact results in relative sliding. In this paper, the interaction force between cable and membrane is transferred through frictional contact action, and as a result, the friction coefficient must be taken into consideration for the form-finding and load analysis of air-supported membrane structures. Eight kinds of P-type membrane materials commonly used in engineering were chosen, and the friction coefficients between the various membrane and cable materials were obtained. The connection between a cable and a membrane of an air-supported membrane structure is considered a contact problem, and its initial shape analysis and wind load response analysis are carried out. The influence of the friction coefficient of a cable membrane on the wind-induced response of an air-supported membrane structure is discussed, and the results are compared with those of the cable-membrane binding model under wind load.

Initial Shape Analysis and Experimental Study of Air-Supported Membrane Structure Considering Cable–Membrane Contact

The cable net and membrane of the air-supported membrane structure transmits the load through mutual extrusion, and the contact interaction between the cable net and membrane should be considered in the initial morphological analysis stage. In this paper, a scale model was designed according to a large-span air-supported membrane structure engineering project, and the shape and force of the structure were measured. At the same time, a finite element model of cable–membrane contact was established, and its interaction behavior was regarded as a combined contact state and sliding contact state. The results show that the influence of different contact state analyses on the prestress of the cable net is obvious, and the influence of the sliding contact between the cable and the membrane should be considered in the design of the membrane structure.

Wind-induced response monitoring of large-span air-supported membrane structure coal-shed under the influence of typhoons

Air-supported membrane structures are being widely used for coal-sheds or the enclosed buildings of stockyards. With the emergence of new functional requirements for buildings, the demand for an increase in both the span and size of air-supported membrane structures has been rapidly increasing in China. Till now, the largest span and length of structures in China have reached 200 m and 1300 m respectively. For air-supported membrane structures, the load-bearing capacity comes from the difference in air pressure between the interior and exterior, which causes the structure to be sensitive to wind and snow loads. This paper studies the wind-induced response of a constructed air-supported membrane structure for a coal-shed cover building with a span of 115 m and width of 317 m, which is located in the southeast coastal city of Yueqing in Zhejiang Province. It is well known that the typhoon-induced response is closely related to the safety and stability of the structure. To ensure the safety of the structure, a newly improved Structure Health Monitoring System (SHMS) has been implemented on a membrane building which is one of the largest scale field monitoring projects anywhere in the world, from where the wind-induced response data was obtained for this paper. Based on the measured wind speeds, the wind pressure distribution coefficient of the membrane surface is derived by numerical simulation with Fluent software. Meanwhile, the displacement response is also calculated by ANSYS APDL. Detailed simulation results and field measurement data are compared for the displacement response caused by Typhoon “Chan-Thu”. It is shown that the former is larger than the latter with the treatment of equivalent wind load. However, the extreme value of the displacement response of the structure with consideration of fluctuating wind load is relatively much more consistent with the measured value. In conclusion, the wind-induced displacement response calculated by the equivalent static wind load method controlled by the principle of maximum displacement equivalence is suitable for engineering applications and wind resistance design, which will result in a slightly higher displacement response evaluation than the real cases.

Influence of different cable–membrane connection models on wind-induced responses of an air supported membrane structure with orthogonal cable net

Long-span air supported membrane structures are typical wind sensitive buildings, wind load is often their control load. The existing analysis of air supported membrane structures basically assumes that the nodes of the cable net and membrane are bound together, the slide or separation between the cable net and the membrane under wind load is not considered. The lack of cable–membrane​ contact model causes hidden danger to the safety of wind resistance performance of long-span air supported membrane structures. In this paper, ANSYS software is adopted for structural analysis, the cable net of air supported membrane structure is divided into many small cable segments, and nodes of all cable segments form point-surface contact pairs with the membrane surface, the joints of all cable segments may bond, slide or separate from the membrane surface. The cable–membrane contact model is used to analyze the wind-induced response of an air supported membrane structure with orthogonal cable net, and the results are compared with the wind-induced response of the cable–membrane binding model. The analysis results of the two models show that: when the cable–membrane contact model is adopted, the displacement and stress responses of the membrane are greatly increased under strong wind load due to the separation of the membrane and the cable net, the axial force distribution of the cable is more uniform due to the sliding between the cable net and membrane. The cable–membrane binding model overestimates the restraint effect of cable net on membrane, in order to better optimize the design of long-span air supported membrane structures, it is necessary to consider adopting cable–membrane contact model.

Numerical simulation of snowdrift on an air-supported membrane structure and response analysis under snow loads

The air supported membrane structure is a typical nonlinear flexible long-span space structure, the wind-induced drift and the resulting accumulation and distribution of snow particles on the structure may be the primary design concern among all loads in heavy-snowfall region. Thus, an accurate prediction of snow distribution on membrane surface is vital to structural design. A numerical simulation method is used to estimate snowdrift in this paper. Based on Euler-Euler method in multi-phase flow theory, this numerical model adopted Mixture model and combined with the snow deposition and erosion model, the snowdrift on an air-supported membrane coal shed is simulated, the distribution factor for roof snow load is given under different wind speed and different directions to estimate the worst load case, snow load on the air-supported membrane structure is significantly affected by snowdrift which causes significant non-uniform snow load. Furthermore, the response analysis of the air-supported membrane structure under snow load is studied, for comparison, uniform snow load case, non-uniform snow load case, and simulated snow load case under 0° wind direction are all considered. The results show that non-uniform snow load caused by snow drifting is more dangerous and should be considered.

Experimental and simulation analysis of the initial shape of a large-span air-supported membrane structure

In recent years, air-supported membrane structures have been widely used in China’s environmental protection of closed coal yards and in sports stadiums. There have been breakthroughs year by year in the numbers constructed, unit area, and span. At present, the largest span of an air-supported membrane structure coal shed has reached 198 m. As the span increases, the force-bearing performance of the structure is more closely related to its shape. In this paper, based on a 225m×198m×66m(Length × width × height) long-span air-supported membrane structure test model, the form-finding and state-finding analysis of the air-supported membrane structure with longitudinal and transverse cable nets were carried out, and the results were compared with the forming test results. The results show that the prestressed state of the structure obtained by the state-finding analysis is closer to the test results. However, there is a specific difference with the target height. At the same time, the form-finding analysis can accurately find the target height, but the structure’s cable force and section shape are quite different from the test results.

Investigation on thermal environment and heat transfer characteristics in ice rinks with different envelopes

Ice rinks are a special kind of building with strict indoor requirements and high energy consumption. Indoor thermal environment along with heat and mass transfer in ice rinks with different envelopes are worthy of investigation. On-site measurement was carried out in two recreational ice rinks with different envelope materials. The average air temperature and humidity in the ice field were 8.7 °C, 6.2 g/kg in the concrete structure Rink A while 12.4 °C, 7.9 g/kg in the air-supported membrane structure Rink B. Severe problems of dew condensation, fogging and frosting were observed in Rink A while only frosting occurred in Rink B. The refrigeration load on a typical summer day was 4689 kWh in Rink A and 5611 kWh in Rink B. Long-wave radiation accounts for the most important part in both rinks with a proportion over 44%. By virtue of applying low-emissivity coating on the ceiling, refrigeration load can be reduced by 53.2%. Applicability of air-supported membrane structure in recreational ice rinks is discussed. The current research is beneficial for the design and operation of ice rinks.

In-situ measurement of structural performance of large-span air-supported dome under wind loads

To comprehensively understand the wind-induced response of air-supported membrane structure, a structural health monitoring system is designed and firstly installed on a pneumatic membrane sports hall with large span. Consisting of four sub-systems, this system was applied to perform a long-term in-situ monitoring. Structural vibration data of outer fabric membrane and steel cable tension strain were acquired during the passage of typhoon Lekima in 2019, as well as internal pressure and wind pressure posed on the structure.Natural frequency and damping ratio are identified based on acceleration data. First five modes are obtained with natural frequencies ranged from 0.279 Hz to 0.457 Hz. Damping ratios approximates 1.5%. Modal shapes are mainly along with lateral and vertical directions. Besides, monitoring results show that the internal pressure of the pneumatic sports hall slightly fluctuates with the structural geometry variation induced by external wind. Windward pressure and wind suction at roof top are primary factors affecting the deformation of outer fabric membrane and cable strain. Specifically, with wind intensity increasing the structure geometry changes from semispherical to conical shape in side view and is twisted by the moment induced via wind load. It is also found that cables at roof ridge area have larger strain than those close to roof edges.

Deflation and collapse of air-supported membrane structures

Air-supported membrane structures are widely used in stadiums, malls, and museums. The stiffness and shape of such structures are dependent on the pressure difference between the indoor and outdoor environments. As the leakage of indoor air may lead to the collapse of the structure, it is necessary to study the deflation deformation process, including the properties that can cause air-supported membrane structures to collapse. In this study, a rectangular air-supported membrane structure is fabricated using a PVC-coated polyester fabric membrane with dimensions of 38 m × 20 m × 7 m, and a leakage experiment is performed. The relationship between the initial leakage area and the pressure difference is obtained, and a new algorithm to determine the equivalent initial leakage rate is proposed. A collapse test is then conducted, with results illustrating that there are two distinct phases of collapse. There is a quick drop in the pressure difference in the first phase, whereas the pressure difference declines rather slowly in the second phase. Computational formulae for collapse and escape times are established, and finally, a quasi-equilibrium status-based algorithm to determine the collapse time of air-supported structures is proposed. Using the new algorithm, several main parameters that influence the collapse of air-supported structures are studied, including the cables, initial pressure, and leakage area. Results show that the initial pressure has a minimal effect on the collapse of structures, while excessive cables accelerate the process of collapse.

Structural behavior of joined hemispherical-cylindrical air-supported membrane structure under vertical loading deflation

The structural behavior of an air-supported structure with long span and large volume probably experiencing severe deflation in a massive snow weather deserves in-depth assessment study for occupant’s safe evacuation. This article presents experimental and numerical studies on the loading deflation process of a 1:10 scale joined hemispherical-cylindrical air-supported structure, whereby three different sandbag loadings were respectively applied on the hemisphere in each test to study the effect of vertical loads to collapse process. Numerical models based on the vector form intrinsic finite element method were employed to predict the deflation responses of the structure under the three loading cases. The structural behavior was evaluated by the pressure response, the wrinkling distribution and development, and the structural collapse mode. A comparison of their pressure responses and structural deflated forms is made to evaluate the contribution of external loading to the deflation progress and the collapse mode. It is found that the pressure will decrease quickly first and then remain relatively stable at a higher level in response to a larger vertical load in addition to the membrane weight. Due to pressure reduction during deflation, the structure loses tension stress in vertical direction so that vertical wrinkles develop in addition to local wrinkles due to external loading. The vertical loading determines distribution of wrinkles in the structure hence produce different collapse progresses for the three loading deflation cases, and accordingly changes the residual pressure it needs to hold its deflated form. Accordingly, the study proposes a feasible method for residual pressure estimation by identifying the distribution of critical residual pressures at different heights from the equilibrium equation of vertical forces. The full-scale structure presents similar structural behaviors when subjected to snow loading deflation, and the feasible method is valid to predict its residual pressure.

Numerical study on the effects of opening form on the deflation for an air-supported membrane structure

Air-supported membrane structure has been widely applied to large-span space due to its advantages of light weight, low cost, reusability. The static load bearing capacity and the dynamic deployment simulation of air-supported membrane structure have received extensive attention. However, very few studies have been reported to investigate its deflation behavior. Although several dynamic finite element algorithms can be applied to the deflation simulation, their computational costs are large. The concept of critical pressure point was introduced in this paper, by which the deflation process was divided into two stages of decompression and collapse. A series of numerical simulations were performed to study the effects of opening area and position on the pressure change in decompression process for air-supported membrane structure. The study showed that the required time for the critical pressure point reached initially decreases sharply gradually evolving into a slight decrease as the opening area increases from 0.5 to 6 m2, which followed a power equation as a function of opening area. Moreover, for a fixed opening area, opening position at top exhibits a minimum value followed by middle position, while a maximum value is shown when the opening is at bottom position. It is obviously that the decompression phase is affected significantly by the opening area and position. The above results have a certain meaning for safety assessment of personal evacuation under emergency deflation of the air-supported membrane structure.

Deflation behavior and related safety assessment of an air-supported membrane structure

As a large span structure that might serve many occupants, the deflation behavior of an air-supported membrane structure under emergency deflation is of critical importance for safety assessment on occupants' evacuation but has received few studies. This paper presents experimental field tests and numerical simulations on deflation behaviors of a real-life air-supported membrane structure. A numerical model is employed in deflation simulation which considers tension-only membrane based on the vector form intrinsic finite element method for membrane motion analysis and pressure change due to air loss in deflation according to the classic thermodynamics. The correctness and the applicability of the model are verified by good correlation of prediction in response of pressure, displacement, and wrinkling formation and development of the structure with those measured and observed in deflation tests. The study shows that the structure in emergency deflation will lose its high pressure quickly first, and then sustain deflating under low residual pressure for a long time. The model is further used in parametrical analysis on factors that affect deflation progress and a complete deflation simulation to predict the whole collapse process, which is accordingly characterized by two typical phases, the tender deflation stage and the severe deflation stage. In tender stage the structure holds a relatively plump form, while in the severe stage the structure bears low decreasing residual pressure, membrane losses most tension stress so that many elements wrinkle and the structure experiences instability. Due to wrinkling, the residual pressure is found to approximately balance with its vertical loads. As a result, the feasible method proposed based on the residual pressure in deflation is very simple and reliable to predict the deflation duration and evaluate maximum escape area for deflation assessment of the studied structure.