Tensioned Membrane Structure Research Articles

Construction of Long-span Tensioned Membrane Structure in Zhijiang Feihu Sports Center

<p>Based on the author's experience in the past twenty years, this paper describes the construction process of membrane structure of space structure. The construction process of long-span tensioned membrane structure is mainly introduced.</p>

Mechanical characteristics analysis of corner tensioned rectangular thin membranes

This paper presents the calculation of the stress distribution of corner tensioned rectangular thin membrane based on the stress superposition method (SSM). By comparing with the results of finite element simulation, the theoretical results of stress distribution of tensioned membrane structure are verified. Based on SSM and free vibration calculation theory, the effects of tension boundary parameters on membrane stress distribution and models are investigated. The influence of corner tension on the mechanical characteristics is analyzed for the corner tensioned rectangular membranes with different aspect ratios. The formula for each order's fundamental frequency ratio of atmospheric to spatial environment is proposed. Conducting the dynamics experiment of a rectangular tensioned membrane, the theoretical analysis is verified by the experimental modal results.

Damping characteristics of the architectural coated fabric and its influence on the vibration response of membrane structures

The influence of material damping is ignored in the current membrane structure design. Based on the damping characteristics of coated fabric obtained by the dynamic mechanical analyzer, the applicability of classical Maxwell model, generalized Maxwell model, three-parameter liquid model, fractional derivative Maxwell model, and fractional derivative Kelvin model to describe the viscoelastic properties of coated fabric were discussed. The free-falling body excitation vibration test of plane tensioned membrane structure is carried out and the dynamic response of plane membrane structure under impact load was studied. The reasonable viscoelastic damping constitutive model is obtained through a systematic comparison of the existing models then implemented in Abaqus software and subsequently validated with the data obtained from the vibration test. Taking saddle-shaped and umbrella-shaped membrane structures as research objectives, the dynamic response of membrane structures under dynamic wind load considering material damping performance is discussed. The results show that the damping property of the coated fabric significantly affects the dynamic characteristics of the membrane structure. Due to the existence of material damping, the modal frequency of the overall structure is greater than the result of the elastic model. The reduction factor of maximum vertical displacement can reach 67.14%, and the reduction factor of maximum principal stress can reach 68.93%, which makes the structural design safety factor high.

Aero-elastic behavior of open-type one-way tensioned membrane structure models

Wind tunnel tests were conducted on an aero-elastic model of an open-type one-way tensioned membrane to investigate the aero-elastic instability mechanism of membrane structures. The structural response and wind velocities above the membrane were measured and analyzed. Complementary simulations were carried out to explain the interaction between the wind and the structure. The results indicate that the aero-elastic instability of the membrane is a kind of vortex induced vibration. This kind of instability is characterized by a sudden increase in the amplitude, or a sudden change in the dominant vibration mode, when the coming flow velocity exceeds a certain value. The vortices generated around the time-averaged deformation of the membrane lead to vortex induced vibration when the dominant frequency of the vortices is close to a certain natural frequency of the membrane. When the aero-elastic instability occurs, the frequency of the vortices is locked in by the structural vibration within a certain coming flow velocity range, and the total damping ratio of the vibration decreases dramatically and becomes nearly zero. Finally, the critical wind velocities are defined, and the reduced critical wind velocities corresponding to the first and second aero-elastic instabilities are 0.84 and 2.3 approximately.

Membrane Structures with Half-Costa Surface in YZ-Plane

This paper presents the computational form-finding analysis of half-Costa tensioned membrane structure model in YZ-plane with different boundaries. The computational form-finding analysis is carried out based on nonlinear analysis method. The tensioned membrane structure in the form of half-Costa models in YZ-plane with different geometry have been found to converge with least square error of total warp and fill stress deviation. The outcome of this paper can serve as a reference in selecting satisfactory parameters to allow the performance increase of tensioned membrane structure in the form of half-Costa in YZ-plane respected to their boundary condition. These models will be selective forms of tensioned membrane structure for design engineers and architect to ponder on as it is a resource efficient structure hence preventing further damage to the environment.

Thermal Sensation Assessment at Different Types of Covered Outdoor Spaces in Barranquilla - Colombia

The notion of comfort applies to productivity, hygiene and air treatment and to the dimensions of sustainability and energy saving. This research analyzes thermal sensation and microclimatic conditions at several outdoor spaces with different combinations of parameters: artificial cover, vegetation cover and without cover. The evaluation scale used in this study is the seven-point ASHRAE scale, which is used to determine people’s psychological reactions to these spaces. The results show that the cover material affects the air temperature and thermal conditions of the spaces. The best thermal comfort conditions were found under trees and a tensioned membrane structure. These cover materials act by blocking radiation and projecting shade on pedestrians, the floor and the walls, which influences the thermal sensation. The results of this research are intended to contribute knowledge for the development of urban design guidelines that take into consideration the microclimatic conditions of tropical cities.

Reliability-based calibration of partial factors for the design of membrane structures

Membrane structures are widely used because of their lightweight properties and expressive architectural shapes. However, there does not yet exist a unified design approach for membrane structures as is available for conventional buildings. Because of their flexibility, membrane structures exhibit a different structural behaviour than conventional buildings. Membrane structures are doubly curved, prestressed and the prestress contributes to the stiffness. The structural response of these structures is non-linear, and the hanging and arching directions interact.A probabilistic framework for tensioned membrane structures is developed herein. Using this tool, partial factors are calibrated for a representative tensioned hypar membrane structure made of PVC-coated polyester fabric. Reliability analyses are performed using a First Order Reliability Method in combination with Latin Hypercube Sampling. The approach is illustrated for two load cases, i.e. considering snow load and wind uplift load, respectively. Three hypars are investigated, each with a different rise to span ratio.The partial factors are determined through a minimisation process. As a result of the performed process, the recommended partial factor for prestress is 1.0, for snow load is 2.0 and for wind uplift load is 2.0 for the investigated membrane structure. In this study, the hanging direction under snow load proves to be decisive for the calibration of the partial factors. The obtained partial factors are not in line with the partial factors found in the Eurocode (1.5 for variable loads). Alternatively, when considering a partial factor for snow load and wind uplift load of 1.5, partial factor for prestress should be increased to 1.2 for the structural type which have been investigated.The application of Latin Hypercube Sampling in combination with the structural analysis of membrane structures enables to perform the reliability analysis calculations in a more computationally efficient way. Moreover, the used optimisation procedure for the calibration of the partial factors makes it possible to interpret the obtained results with respect to the complex non-linear behaviour of the investigated tensile membrane structures.

Vibration monitoring of an open-type one-way tensioned membrane structure based on stereovision

Membrane structures are lightweight and flexible, and the responses of them are of great importance to evaluate the dynamic characteristics. However, when observing the dynamic responses by using conventional measurements (e.g., laser displacement meter), there are several disadvantages, such as high-cost, low sampling efficiency, and only one-dimensional data being obtained, especially for the membrane structures in the field of civil engineering. Therefore, a stereovision measurement is organized by proposing a series of algorithms which are based on a newly built mathematical model. The calibration toolbox based on OpenCV is adopted for the camera calibration. After that, edge detection, determination of central pixel coordinates, continuous tracking, and matching of circular feature points between different images are solved in the process of image processing. Finally, the new-formed stereovision measurement system is adopted to observe the responses of an open-type one-way tensioned membrane structure in free-vibration and aeroelastic wind tunnel test. After the feasibility and validity of this measurement system are verified, the full field displacement distributions of this tensioned structure under different wind speeds are presented. This successful application implies that such stereovision measurement can make up the disadvantages of the conventional measurements. Such stereovision measurement can be used to measure the responses of the structures in the field of civil engineering.

Experimental Study and Simulation of Film Tension Measurement by Apex Method

In order to ensure the normal use of the tensioned membrane structure, it is necessary to effectively detect the tension applied to the tensioned membrane surface. In this paper, a top-projection membrane surface tension measuring instrument with fixed boundary was designed. During the measure process, the force and the apex displacement were measured simultaneously to obtain the calibration curve group of force and abutment displacement. Compared with the traditional apex method, the measuring instrument eliminates the influence of the membrane structure boundary on the measurement results, and the measurement results were accurate and reliable. The correctness of the device is verified by numerical simulation and experimental results. Theoretically solved the technical problem of rapid measurement of membrane surface tension, and obtained stable results in actual measurement, thus providing a new method for membrane surface tension measurement.

Nonlinear wind-induced instability of orthotropic plane membrane structures

he nonlinear aerodynamic instability of a tensioned plane orthotropic membrane structure is theoretically investigated in this paper. The interaction governing equation of wind-structure coupling is established by the Von Karman\'s large amplitude theory and the D\'Alembert\'s principle. The aerodynamic force is determined by the potential flow theory of fluid mechanics and the thin airfoil theory of aerodynamics. Then the interaction governing equation is transformed into a second order nonlinear differential equation with constant coefficients by the Bubnov-Galerkin method. The critical wind velocity is obtained by judging the stability of the second order nonlinear differential equation. From the analysis of examples, we can conclude that it\'s of great significance to consider the orthotropy and geometrical nonlinearity to prevent the aerodynamic instability of plane membrane structures; we should comprehensively consider the effects of various factors on the design of plane membrane structures; and the formula of critical wind velocity obtained in this paper provides a more accurate theoretical solution for the aerodynamic stability of the plane membrane structures than the previous studies.

Aging Properties of Polyvinylidenefluoride-Coated Polyesters Used in Tensioned Membrane Structure: Effect of Loading Protocol and Environment

This paper presents the degradation behaviors of polyvinylidenefluoride- (PVDF-) coated polyesters used in tensioned membrane structure by artificial accelerated tests, in which the effects of environment factors and loading conditions are studied. Results show that the degradation ratio of main mechanical parameters (tensile strength, tear strength, and elastic modulus) is related to the aging depth of substrate and coating. The degradation of weather resistance can be considered as the accumulation of environment and loads. The ultraviolet radiation and the temperature mainly affect the mechanical properties of yarns, while the preloading before aging tests can change the crimp degrees and decrease the coating thickness. The effect of loads should not be ignored in the weather resistance analysis of PVDF-coated polyesters. A simplified method composed of cyclic tests and stress-relaxation tests is suggested to study the long-term weather resistance of PVDF-coated polyesters. It can provide a theoretical reference for the proposal of resistance partial factor in the design of tensioned membrane structure.

Research on the wind-induced aero-elastic response of closed-type saddle-shaped tensioned membrane models

The aero-elastic instability mechanism of a tensioned membrane structure is studied in this paper. The response and wind velocities above two closed-type saddle-shaped tensioned membrane structures, with the same shape but different pretension levels, were measured in uniform flow and analyzed. The results indicate that, for most wind directions, several vibration modes are excited and the amplitude and damping ratio of the roof slowly increase with the on-coming flow velocity. However, for particular wind directions, only one vibration mode is excited, and the amplitude and damping ratio of the vibration mode increase slowly with the on-coming flow velocity. The aero-elastic instability is caused by vortex-induced resonance. On exceeding a certain wind speed, the amplitude of the roof vibration increases sharply and the damping ratio of the vibration mode decreases quickly to near zero; the frequency of the vortex above the roof is locked in by the vibration within a certain wind velocity range; the amplitudes of the roof in these wind directions reach 2–4 times the amplitudes for other wind directions. The reduced critical wind speeds for the aero-elastic instability of saddle-shaped membrane structures at the first two modes are around 0.8–1.0.

张拉平面膜结构非线性振动频率计算分析

利用冯∙卡门薄膜大挠度理论，结合达朗贝尔原理，建立正交异性张拉平面膜结构非线性自由振动的控制方程。然后利用伽辽金法对其进行简化，并采用同伦摄动法进行求解，得到振动频率的近似解析解。通过算例，计算了结构的非线性振动频率，并将本文结果与精确解进行比较分析。分析表明：本文所求得的近似解析解与精确解之间的最大误差小于4%。因此本文的近似解析解与精确解非常接近，且本文所得解形式更为简单，计算也更方便，有利于在工程中进行推广应用。 The nonlinear free vibration governing differential equations for the orthotropic tensioned plane membrane structure are established by Von Karman’s membrane large deflection theory and D’Alembert’s principle. Then the governing differential equations are simplified by Bubnov-Ga- lerkin method and solved by the homotopy perturbation method (HPM), and obtained the ap-proximate analytical solution of the vibration frequency. In the computational example, the non-linear vibration frequency of the structure is computed, and the results of this paper are analyzed and compared with the exact solution. The analysis shows that the approximate analytical solution obtained in this paper is very close to the exact solution (the maximum error is less than 4%), and the approximate analytical solution obtained in this paper is more simple and convenient. This is favorable for the popularization and application in engineering.

Research on the added mass of open-type one-way tensioned membrane structure in uniform flow

The wind pressure on the vibrating membrane can be simplified to be the sum of the aerodynamic acoustic pressure and the quasi-static wind pressure. These pressures are caused by the compressive action of the vibrating membrane on the air and the quasi-static wind pressure on the corresponding membrane at any instant. An analytical expression for the added mass of open-type one-way tensioned membrane vibrating in uniform flow is derived and verified using data from a series of aeroelastic wind tunnel tests. The results show that the added mass caused by the aerodynamic acoustic pressure is equal to 2ρairl/nπ, where ρair is the density of air; l is the span of the membrane and n is the mode order. The added mass caused by the quasi-static wind pressure is equal to ρairU02an/2y0ωs,n2, where U0 is the on-coming flow velocity; y0 is the displacement amplitude; an is the shape-change coefficient and ωs,n is the circular natural frequency of the nth mode. In this study, the difference between analytical and test results is small and within ±9.0%; the added mass caused by the quasi-static wind pressure increases with the on-coming flow velocity and is 2–5 times the component caused by aerodynamic acoustic pressure; and the added mass of the first mode is 3.5–6.9 times the structural mass.

Research on the mechanical properties of membrane connections in tensioned membrane structures

As an important part, the connections generally are important for the overall behavior of the structure and the strength and serviceability of the connection should be ensured. This paper presents the mechanical properties of membrane connections in tensioned membrane structure. First, the details of common connections used in the membrane structure are introduced. Then, the common connections including membrane seam, membrane-flexible edge connection and membrane-rigid edge connection are tested and the corresponding failure mechanisms are discussed. Finally, the effects of connection parameters on the connection strength are investigated and proper connection parameters are proposed. The strength reduction factors corresponding to different connection types are proposed, which can be references for the design and analysis of membrane structures.

Defects of Tensioned Membrane Structures in the Tropics

The wide use of tensioned membrane structures (TMS) is prominent in many designs because of its aesthetic, ergonomic, and economical nature. Recently, TMS has been applied in the tropics with success, yet defects specific to this region have received little attention. Through a questionnaire survey of 890 users and technicians of TMS in three different areas in Malaysia, this study identified the most frequently occurring TMS defects in the tropics, such as of roof coatings, or fatigue in fixings, fungal decay, mold growth, and dirt in membrane, in anchor cables, and degradation of fabrics. These defects are quite different from those in other climatic zones. The top five causes of TMS defects in the tropics are weather, aging, design, construction/installation, and material selection. However, only or fatigue in fixings is a significant predictor for of roof coatings. While this is not a causal effect, a practical implication is that TMS maintenance workers do not have to climb up to the roof to check the deterioration in coating but only need to predict the deterioration through the corrosion levels of the fixings. Further, seven countermeasures for TMS defects in the tropics are recommended. This study is the first comprehensive study examining tensioned membrane structure defects in the tropics.

Tensioned Membrane Structures in the Form of Egg Shape

Tensioned membrane structures are pre-stressed membrane structures that are appropriate to be used for long span application. Tensioned membrane structures must depend on their shape and internal pre-stress alone to achieve stability and to carry the loads. Some of the largest stadiums, airports, convention halls and commercial places are tensioned membrane structures. It is essential to perform shape-finding analysis while dealing with tensioned membrane structures. In this study, shape-finding analysis is carried out using computer program for stress analysis which is based on theory of nonlinear displacement method. Shape-finding of membrane surface bordered by Egg has been investigated. In this study, the possibility of adopting the form of Egg as surface shape for tensioned membrane structure has been studied.

Modal Analysis of Tensioned Membrane Structure of Umbrella-Shaped

The tensioned membrane structure is a typical flexible architecture and is sensitive on the wind loads . We used software ANSYS to do modal analysis of the umbrella-shaped membrane structure and analyzed the natural vibration characteristics. We focused on the effect of design parameters on structural modal. The results show that the natural frequency of umbrella-shaped membrane structure mainly depends on membrane prestress and membrane tension stiffness.

Flexible Porous Wave Barrier for Enhanced Wetlands Habitat Restoration

A flexible porous wave barrier is proposed to increase the effectiveness of wetlands habitat restoration projects by protecting cordgrass seedlings from wave action during the critical initial stages of growth following planting. The barrier consists of a vertical porous membrane anchored to the sea bed and kept under tension by a small buoyant float. The structure is easily constructed, requires little maintenance, and may be deployed from a small boat without the need for specialized equipment or trained personnel. A numerical model is developed to assess the effectiveness of this structure as a barrier to wave action. The fluid motion is idealized as linearized, two-dimensional potential flow and the equation of motion of the structure is taken to be that of a one-dimensional beam of uniform mass per unit length subjected to a constant axial force. The boundary integral equation method is applied to the fluid domain, and the dynamic behavior of the structure is also described through an appropriate Green function. Numerical results are presented that illustrate the effects of the various wave and structural parameters on the wave reflection characteristics of the structure. Small-scale physical model tests have also been carried out in the University of Houston wavetank facility to validate the predictions of the numerical model. In general, good agreement was obtained between the theoretical and experimental reflection coefficients. It is found that for certain structural parameter combinations a porous tensioned membrane structure may provide a reasonably effective barrier in the short- to mid-wavelength range.