Viscoelastic Damper(VED)

A Viscoelastic Damper (VED) is a crucial energy-dissipating and vibration-damping device widely applied in building structures, bridge engineering, and various structural systems requiring vibration control. Its core function is to convert mechanical energy generated by structural vibrations into thermal energy through its own energy-dissipating mechanism, thereby significantly reducing the vibration response of structures under wind loads, seismic actions, or other dynamic loads, and protecting the safety and stability of the structures.

Viscoelastic dampers operate based on the unique mechanical properties of viscoelastic materials, such as special rubbers and polymer materials, which exhibit both viscous and elastic characteristics. Under external dynamic loads, the restraining components (typically metal plates) of the damper undergo relative displacement, driving the viscoelastic material to produce shear or tensile-compressive deformation.
During the deformation of the viscoelastic material, frictions and slips occur between molecular chains, along with the stretching of chain segments. This process is accompanied by the breaking and recombination of reversible bonds between molecules, through which mechanical energy is continuously converted into thermal energy, achieving efficient dissipation of structural vibration energy. Moreover, due to the characteristic that the strain of viscoelastic materials lags behind the stress, the damper forms a hysteresis loop during loading and unloading, and the area enclosed by the loop represents the energy dissipated by the damper.

1, Viscoelastic Damping Material
1). Core Material Properties
As the key component of the damper, the viscoelastic damping material must possess excellent viscoelastic properties, maintaining stable energy-dissipating capacity across a wide temperature range and frequency spectrum. Common materials are made from silicone rubber, natural rubber, butyl rubber, nitrile rubber, etc., as base materials, added with specific fillers and additives through special processes. These materials have a high loss factor (generally between 0.3 and 0.8), meaning they can effectively convert mechanical energy into thermal energy.
2). Material Selection and Customization
According to different engineering application scenarios and performance requirements, viscoelastic materials can be customized. For example, silicone rubber-based materials with high temperature resistance can be selected for high-temperature environments; for structures with high requirements for stiffness and damping, material performance can be optimized by adjusting the material formula and manufacturing process.
2, Restraining Components
1). Function and Material of Metal Plates
Restraining components generally use high-strength metal plates, such as Q235 low-yield-point steel or other alloy steels. The main role of metal plates is to constrain the deformation of viscoelastic materials, guiding them to produce the required deformation mode (such as shear or tensile-compressive deformation) in a specific direction, thus giving full play to the energy-dissipating capacity of viscoelastic materials. Meanwhile, metal plates must have sufficient strength and stiffness to withstand the loads transmitted by the structure.
2). Design and Manufacture of Metal Plates
The shape, size, and connection mode of metal plates are specially designed according to the type of damper and application scenarios. For example, in shear-type viscoelastic dampers, metal plates are usually designed as parallel multi-layer structures, alternately laminated with viscoelastic materials through adhesives; in tensile-compressive dampers, metal plates may adopt structural forms such as sleeves and flanges combined with viscoelastic materials to ensure cooperative operation during stress.
3, Adhesives and Sealing Components
1). Importance and Performance Requirements of Adhesives
Adhesives are used to firmly bond viscoelastic materials to restraining components, ensuring no relative sliding between them during long-term use and guaranteeing the normal working performance of the damper. Therefore, adhesives must have high bonding strength, good durability and weather resistance, as well as good compatibility with viscoelastic materials and metal plates. Common adhesives include epoxy resin and polyurethane types.
2). Functions of Sealing Components
In dampers with high environmental sealing requirements, such as those applied in humid or corrosive environments, sealing components are set up. They mainly prevent external media (such as water, moisture, corrosive gases, etc.) from invading the interior of the damper, affecting the performance of viscoelastic materials and metal components, thus ensuring the long-term reliability and stability of the damper.

1, Classification by Deformation Mode
1). Shear-Type Viscoelastic Damper
(1). Working Mechanism: This type of damper mainly relies on the shear deformation of viscoelastic materials under shear force to dissipate energy. When the structure is subjected to horizontal forces (such as wind loads or horizontal seismic actions), the relative displacement of the damper causes shear strain in the viscoelastic material layers, achieving vibration reduction through molecular friction and energy-dissipating mechanisms within the material.
(2). Application Scenarios: Widely used in frame beam-column joints, shear wall coupling beams, and other parts of building structures, as well as pier-beam connection parts of bridge structures, effectively reducing the horizontal vibration response of structures.
2). Tensile-Compressive Viscoelastic Damper
(1) Working Mechanism: Tensile-compressive dampers function when the structure is subjected to axial tensile-compressive loads. When structural components undergo axial deformation, viscoelastic materials produce corresponding tensile or compressive deformation under tensile-compressive stress, consuming energy through the viscoelastic energy-dissipating characteristics, while providing certain axial stiffness and damping to the structure.
(2) Application Scenarios: Commonly used in structural components to bearing the axial forces, such as inter-column braces in building structures and stay cable dampers in bridge structures, significantly controlling the axial vibration and deformation of structures.
2, Classification by Shape and Structure
1). Flat-Plate Viscoelastic Damper
(1). Structural Features: The flat-plate damper has a relatively simple structure, usually composed of multiple layers of metal plates and viscoelastic materials alternately laminated, driving the deformation of viscoelastic materials through the relative displacement between metal plates. It is in the shape of a flat plate, and its size and specifications can be customized according to engineering needs.
(2). Application Advantages: It has the advantages of convenient installation and small space occupation, suitable for in-plane vibration reduction of various building structures, such as setting flat-plate dampers in the floor slabs, walls, and other parts of buildings to effectively reduce the inter-story displacement of structures under horizontal vibration.
2). Cylindrical Viscoelastic Damper
(1). Structural Features: The cylindrical damper generally uses a cylindrical metal shell as the restraining component, with viscoelastic materials filled inside, and setting up structures such as piston rods or pistons. When stressed, the movement of the piston rod or piston causes the deformation of viscoelastic materials, thus achieving energy dissipation and vibration reduction.
(2). Application Advantages: This type of damper has high strength and stability, capable of withstanding large loads and deformations, suitable for large-scale structural engineering, such as the main towers of bridges and the core tubes of large buildings, providing strong damping force and energy-dissipating capacity for structures.

1, Advantages
1) Efficient Energy-Dissipating Capacity: Viscoelastic dampers can start to dissipate energy under small vibration amplitudes, showing good adaptability to vibrations of different frequencies and amplitudes. With a full hysteresis loop and strong energy-dissipating capacity, they can effectively reduce the response of structures under dynamic loads and reduce the risk of structural damage.
2) Providing Additional Stiffness and Damping: They can not only increase the damping ratio of structures to reduce vibration response but also provide certain additional stiffness to structures, improve the dynamic characteristics of structures, and enhance the lateral displacement resistance, especially suitable for flexible structures with small stiffness and long natural vibration periods.
3) Simple Structure and Convenient Installation: Compared with some complex vibration-damping devices, viscoelastic dampers have a relatively simple structure, mainly composed of viscoelastic materials and restraining components, without the need for complex mechanical transmissions or electronic control components. Their installation methods are similar to those of ordinary structural components, which can be installed and maintained on construction sites using conventional methods such as welding and bolt connection.
4) Wide Application Range: Applicable to various building structures (including multi-story, high-rise, and super-high-rise buildings), bridge engineering (long-span bridges, viaducts), industrial equipment foundations, and other structural systems requiring vibration control. Whether for new projects or seismic reinforcement and vibration-damping renovation of existing structures, viscoelastic dampers can play an important role.
2, Limitations
1) Temperature Sensitivity: The performance of viscoelastic materials is significantly affected by temperature. In high-temperature environments, the stiffness and damping of materials decrease, and the energy-dissipating capacity declines; in low-temperature environments, materials may become brittle, losing part of their viscoelastic properties, leading to unstable damper performance. Therefore, when designing and applying viscoelastic dampers, the temperature change range of the use environment must be fully considered, and corresponding temperature compensation measures or appropriate material formulas should be adopted.
2) Frequency Dependence: The energy-dissipating effect of dampers varies with different vibration frequencies. For certain specific frequencies of vibration, their best performance may not be fully exerted. In practical engineering applications, structural dynamic analysis is required to reasonably design the parameters of dampers, so that they can work effectively within the main vibration frequency range of structures.
3) Long-Term Performance Degradation: Although the design service life of viscoelastic dampers usually matches that of building structures, their performance may gradually degrade during long-term use due to material aging, fatigue, and environmental factors. Therefore, regular inspection and maintenance of dampers are necessary, and replacement should be carried out when necessary to ensure their long-term reliable vibration-damping effect.

1. Technical Parameters
The following are examples of technical parameters for common viscoelastic dampers. The actual product parameters can be customized according to customer request and engineering application scenarios:

2. Basic Mechanical Properties of Viscoelastic Dampers

1, Raw Material Quality Management
1) Supplier Management: Establish strict supplier screening and evaluation mechanisms, cooperating only with raw material suppliers with good reputation, stable production capacity, and a sound quality assurance system. Conduct on-site inspections of major raw material suppliers, such as viscoelastic materials, metal plates, and adhesives, auditing their production processes, quality control procedures, testing equipment, and personnel qualifications to ensure the stability and reliability of raw material supply.
2) Raw Material Inspection: All raw materials must undergo strict inspection before entering the factory. Key performance indicators of viscoelastic materials, such as hardness, tensile strength, loss factor, and glass transition temperature, need to be tested using professional equipment such as dynamic mechanical analyzers (DMA); metal plates should be inspected for their material certificates, mechanical properties (yield strength, tensile strength, elongation, etc.), surface quality, and dimensional accuracy; adhesives should be tested for their bonding strength, curing time, weather resistance, and other properties. Only qualified raw materials can be stored for use, and unqualified materials are resolutely returned.
2, Production Process Quality Management
1) Process Control: Formulate detailed and strict production processes and operation specifications to ensure the standardization and standardization of the production process. All links, from the mixing and molding of viscoelastic materials, to the processing and surface treatment of metal components, to the assembly and bonding of dampers, must be carried out in strict accordance with process requirements. During production, key process parameters (such as temperature, pressure, time, etc.) are monitored and recorded in real time to ensure the stability and consistency of process parameters.
2) Quality Inspection: Set up multiple process inspection links to inspect the quality of semi-finished and finished products during production. After each process is completed, operators must conduct self-inspection, and only after passing can it be transferred to the next process; full-time quality inspectors conduct sampling or full inspections of semi-finished and finished products according to inspection standards and plans, checking contents such as dimensional accuracy, appearance quality, and bonding quality. For products that do not meet the quality requirements, rework or scrapping is carried out in a timely manner, and the causes are analyzed, and corrective and preventive measures are taken to prevent the problem from recurring.
3, Finished Product Quality Management

1) Performance Testing: Finished dampers must undergo comprehensive performance testing to verify whether they meet design requirements and product standards. Performance testing items include damping force testing, hysteresis loop testing, fatigue performance testing, temperature performance testing, etc. Through special mechanical performance testing equipment, the load conditions under actual working conditions are simulated, and various performance indicators of the dampers are accurately measured and evaluated. Only products with all performance indicators meeting the requirements can be determined as qualified products.
2) Quality Traceability: Establish a perfect product quality traceability system, assign a unique product number to each finished damper, and record the whole process information from raw material procurement, production processing, quality inspection to finished product warehousing. Once a quality problem occurs in the product during use, each link in the production process can be quickly traced through the product number, and the cause can be found in a timely manner and corresponding solutions can be taken.

4, Inspection report

1, Domestic Standards
1) National Standards: Strictly comply with the national standard GB 50011-2010 Code for Seismic Design of Buildings (2016 Edition). It specifies detailed regulations on terms and definitions, classification and marking, technical requirements, test methods, inspection rules, as well as labeling, packaging, transportation, and storage of building energy-dissipating dampers. This ensures the product meets national seismic design and engineering application requirements in terms of performance, quality, and safety.
2) Industry Standards: Refer to industry standards such as JGJ/T 209-2010 Technical Specification for Energy Dissipation and Vibration Reduction of Buildings. These standards regulate the design, calculation, construction installation, and acceptance of viscoelastic dampers in building structures, guaranteeing their rational application and reliable performance in construction projects.
2, International Standards
1) U.S. Standards: Reference is made to U.S. standards such as AISC 341 Seismic Provisions for Structural Steel Buildings and ASCE/SEI 7 Minimum Design Loads and Associated Criteria for Buildings and Other Structures. Aligning with international advanced standards in product performance indicators, design methods, and testing requirements enhances the product's competitiveness in the global market.
2) Japanese Standards: Drawing on Japanese standards like JIS A 5651 Seismic Isolation Devices for Buildings, the product benchmarks against requirements for material properties, structural specifications, and performance testing methods. This incorporates Japan's advanced experience in vibration reduction technology to ensure product quality reaches international advanced levels.
3) EU Standards: The product is manufactured in compliance with a series of EU standards including EN 15129:2009 and EN 1337, ensuring superior performance.

1, Construction Engineering
1) Seismic Design for New Buildings: In the seismic design of various new building structures, viscoelastic dampers serve as effective seismic measures. Installing dampers at key structural locations (such as frame beam-column joints, shear wall coupling beams, and bracing systems) significantly enhances the seismic performance of structures. This reduces displacement and acceleration responses under seismic loads, minimizes structural damage, and safeguards the safety of personnel and property within buildings.
2) Seismic Retrofit for Existing Buildings: Using viscoelastic dampers for seismic reinforcement of existing buildings that fail to meet seismic design requirements is an economical and efficient approach. Without large-scale demolition or reconstruction of the original structure, installing dampers at appropriate positions can enhance the energy-dissipating capacity and seismic performance of the structure, comply with current seismic codes, and extend the building's service life.
3) Wind Vibration Control for High-Rise Buildings: In super-high-rise and high-rise buildings, wind loads often become one of the primary control loads for structural design. Viscoelastic dampers can be used to control the vibration of building structures under wind loads, reducing wind-induced vibration responses. This improves building comfort and prevents occupant discomfort or damage to internal facilities caused by excessive wind-induced acceleration.
2, Bridge Engineering
1) Seismic and Vibration Control for Long-Span Bridges: Due to their structural characteristics and large spans, long-span bridges (such as suspension bridges and cable-stayed bridges) are prone to significant vibration responses under earthquakes and strong winds. Viscoelastic dampers can be applied to connection parts between main towers and girders, piers and girders, as well as stay cables of bridges. This effectively reduces vibrations of bridge structures under seismic and wind loads, improving bridge safety, stability, and normal operation.
2) Vibration Control for Viaducts and Urban Bridges: In urban viaducts and general urban bridges, viscoelastic dampers can mitigate vibrations caused by vehicle movement, structural responses under earthquakes, and wind-induced vibrations. Proper damper installation reduces the risk of fatigue damage to bridge structures, enhances bridge durability, and minimizes vibration impacts on the surrounding environment and residents.
3, Industrial Equipment and Infrastructure
1) Vibration Reduction for Large Industrial Equipment Foundations: Large industrial equipment such as fans, cooling towers, and heavy machinery generate vibrations during operation. These vibrations not only affect the equipment's normal operation and service life but also impose adverse impacts on surrounding structures and the environment. Installing viscoelastic dampers on equipment foundations or support structures effectively reduces the transmission of equipment vibrations, improving equipment stability and reliability.
2) Seismic and Wind Resistance for Power Facilities and Communication Towers: In infrastructure such as power facilities (e.g., substation frameworks, transmission line towers) and communication towers, viscoelastic dampers enhance structural disaster resistance under earthquakes and wind loads. By installing dampers, vibration responses of structures during natural disasters are reduced, ensuring the smooth operation of power supply and communication networks.

1, Installation Instructions

1) Pre-Installation Preparations: Before installing viscoelastic dampers, inspect and clean the structural installation site to ensure the surface is flat, free of debris, and oil-free. Meanwhile, verify the damper model, specifications, and quantity against design requirements, and inspect the product for any damage, deformation, or other defects to ensure product quality compliance.
2) Determination of Installation Positions: Strictly confirm damper installation positions according to structural design drawings. Accurate positioning ensures the damper can optimally dissipate energy and reduce vibrations when the structure is loaded. In building structures, dampers are typically installed at key locations such as frame beam-column joints, shear wall coupling beams, and bracing systems; in bridge structures, installation positions include connections between piers and girders, main towers and girders, as well as stay cable anchor ends.
3) Installation Methods and Connection Requirements: The main installation methods for viscoelastic dampers are welding and bolting. For welding connections, ensure welding quality meets relevant standards, with full and firm welds free of incomplete or missed welding. For bolted connections, use specified bolt specifications and tighten them to the design torque to ensure reliable connections. During installation, protect the viscoelastic material and metal components of the damper from collision, scratches, or other damage.

2, Maintenance Key Points
1) Regular Inspections: After viscoelastic dampers are put into use, conduct regular inspections at an interval of generally once a year or as determined by project-specific conditions. Inspection items include damper appearance for damage, deformation, or aging signs, tightness of connection parts, and cracking or detachment of viscoelastic materials. If any abnormalities are found, promptly evaluate and address them.
2) Cleaning and Protection: Regularly clean dampers to remove surface dust, debris, and dirt, keeping the damper surface clean. For dampers in humid or corrosive environments, implement corresponding protective measures such as applying anti-corrosion paint or installing protective covers to prevent metal components from rusting and corroding, which could affect damper performance and service life.
3) Performance Monitoring and Evaluation: When conditions permit, monitor damper performance by measuring parameters such as displacement, strain, and damping force to assess the damper's operating status and performance changes. When the structure experiences major natural disasters (such as earthquakes or strong winds) or the damper shows obvious abnormalities,

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