Experimental and simulation research on elastic adhesive bonded joints

Diesel locomotives use different adhesives for bonding at different locations. For example, elastic adhesives with polyurethane or modified silane components are used for bonding on the front window glass, and rigid adhesives with epoxy or acrylic components are used for aluminum profile inserts. Glue for bonding. In the design process of these bonding structures, it is necessary to verify the strength of bonded joints formed by different types of adhesives, different bonding sizes, and different substrate surfaces. The commonly used verification method is to make corresponding tensile shear joints and test their strength according to GB/T 7124.

This article uses finite element simulation calculations to analyze and calculate the tensile-shear bonding joints formed by polyurethane elastic and epoxy rigid glue, simulate the bonding strength under different base material combinations, and compare the simulation results with the actual test results. After comparison, the results of the two are highly consistent, which is very helpful for batch bonding structure verification work.

2 Test and inspection of bonded joints

2.1 Material selection and testing matrix

Typical adhesives commonly used in the field of rail transit were selected as test verification materials. Polyurethane adhesive A is mainly used for bonding locomotive front windows, side windows and screen door glass, and epoxy adhesive B is mainly used for bonding fiberglass interior interior inserts. . The base materials involved include fiberglass base materials, aluminum base materials, and steel base materials. Since the fiberglass base material used is mainly made of woven fabric and chopped strand felt in its lamination structure, and the paving direction is random, it is considered as an isotropic material.

3 Simulation calculation of bonded joints

3.1 Bonding calculation results of elastic glue

Ansys Workbench software was used to model and simulate the tensile specimen of the adhesive body, and the corresponding calculation results were compared with the test data. Due to the large deformation of the elastic glue, the traditional linear elastic material model was used to simulate the small deformation data. is more accurate. For large deformation data, only other material models can be considered. Different material models have different effects on the simulation results. This article uses the Mooney-Rivlin model, Ogden model, Neo Hookean model, Yeoh model, and linear elastic model for simulation, as shown in Figure 1 below.

The following is a comparison chart between the simulation and experimental results of elastic glue. The red dotted line represents the experimental results, and the other colored curves represent the simulation results of different material models. Through comparison, it can be found that there are many material models that can be used for elastic adhesives. The core material model and simulation method for elastic adhesives developed by Yifa Bonding and Composite Materials Research Institute can better obtain results that are consistent with actual tests. Parameter data, and different material models have been developed for different elastic glues, customized to meet customer development needs, and the simulation calculation results are more convincing.

Left picture: A polyurethane glue bonded to FRP/aluminum plates, right picture: A polyurethane glue bonded to FRP/steel plates

The mechanical simulation of bonded joints is a technical activity, and a professional team does professional work. After years of industry accumulation, Yifa Bonding and Composite Materials Research Institute has developed a series of courses "Design Calculation and Verification of Bonded Joints" to meet the needs of Various industries have growing demands for bonding design. We also have a CNAS-accredited testing laboratory that can issue authoritative third-party testing reports to protect customers' product quality.

Yifa Bonding and Composites Research Institute is the exclusive strategic partner of German Fraunhofer IFAM in China. Conduct EN17460 and DIN2304 certification audits, project support and consulting in China; carry out three levels of bonding: EAE European Bonding Engineer, EAS European Bonding Technician, EAB European Bonding Operator (European Bonding Operator) certificated by Fraunhofer Training and examinations, as well as training and examinations for composite design Composite-D, manufacturing Composite-M, maintenance Composite-R, and technician Composite-S. Special training courses related to customized bonding and composite material applications are also provided.

At present, EAE European bonding engineer training standards have been upgraded from DVS-EWF3309 and EWF517 to EWF662; EAS European bonding technician training has also been upgraded from DVS-EWF3301 and EWF516 to EWF662; EAB European bonding operator training standards have been changed from DVS 3305 and EWF515. for EWF 515.