The mechanical performance testing equipment for civil air defense materials is mainly used to evaluate key mechanical indicators such as tensile strength, yield strength, elongation, compressive modulus of elasticity, flexural strength, and impact toughness of materials used in civil air defense engineering. Its testing techniques cover various types of tests and standardized operating procedures, as follows:
1、 Core detection technology methods
tensile test
Purpose: To determine the deformation and fracture behavior of materials under axial tensile load, and obtain parameters such as tensile strength, yield strength, and elongation.
Method:
Apply axial tension to standard specimens (such as dumbbell shaped or circular sections) using a universal testing machine and record the load displacement curve.
Calculate indicators such as maximum load, elongation at break, and elastic modulus to evaluate the plastic deformation capacity of materials.
Applicable materials: metal, plastic, composite materials, rubber, etc.
Standard basis: GB/T228.1 (metallic materials), ASTM D638 (plastics), GB/T1449 (tensile related parts of the bending performance test method for fiber-reinforced plastics).
compression test
Purpose: To determine the compressive performance and recovery ability of materials under compressive load.
Method:
Apply vertical pressure to the specimen using a compression testing machine and record the relationship between compression deformation and load.
Evaluate the maximum stress and elastic recovery characteristics of materials under constant or increasing loads.
Applicable materials: brittle materials (such as cast iron, ceramics), foam plastics, etc.
Standard basis: GB/T7314 (Compression test method for metallic materials at room temperature).
Bend Test
Purpose: To determine the flexural strength and stiffness of materials when subjected to bending loads.
Method:
Apply bending moment to the specimen using three-point or four point bending loading method, and record the relationship between bending deformation and load.
Calculate indicators such as flexural strength and flexural modulus to evaluate the flexural performance of materials.
Applicable materials: metal, plastic, wood, ceramics, etc.
Standard basis: GB/T232 (Bending test method for metallic materials), ASTMD7624 (Bending properties of polymer based composite materials).
shear test
Purpose: To determine the ability of materials to withstand shear forces (shear strength).
Method:
Apply a shear force parallel to the cross-section of the specimen using a shear testing machine, and record the relationship between shear deformation and load.
Calculate shear strength and evaluate material shear resistance.
Applicable materials: metal, composite materials, wood, etc.
Standard basis: GB/T10007 (Test Method for Shear Strength of Rigid Cellular Plastics).
impact test
Purpose: To determine the impact toughness of materials under impact loads.
Method:
Use a pendulum or drop hammer impact testing machine to apply instantaneous impact force to the specimen and record the impact energy absorption value.
Evaluate the fracture toughness of materials under dynamic loads.
Applicable materials: metal, plastic, composite materials, etc.
Standard basis: ISO179 (Determination of plastic pendulum impact performance), GB/T21239 (Compression performance of fiber-reinforced plastic laminates after impact).
fatigue test
Purpose: To determine the fatigue life of materials under cyclic loading.
Method:
Apply alternating stress to the specimen using a fatigue testing machine and record the number of cycles before fracture.
Evaluate the durability of materials under long-term dynamic loads.
Applicable materials: metals, composite materials, etc.
2、 Testing equipment and instruments
Universal testing machine: integrates multiple testing functions such as tension, compression, bending, and shearing, equipped with high-precision sensors and control systems, can automatically record data and generate reports.
Impact testing machine: divided into pendulum type and drop hammer type, used to determine the impact resistance performance of materials.
Fatigue testing machine: Simulate the fatigue behavior of materials under cyclic loading and evaluate their durability.
Auxiliary equipment: including sample fixtures, extensometers, strain gauges, data acquisition systems, etc., to ensure test accuracy and repeatability.
3、 Testing process and standards
Sample preparation:
Cut the sample according to the standard requirements to ensure dimensional accuracy and surface quality.
For composite materials, it is necessary to check the uniformity of fiber distribution to avoid defects affecting the results.
Equipment calibration
Regularly calibrate testing machines and sensors to ensure data accuracy.
Experimental operation:
Select the appropriate loading rate and environmental conditions (such as temperature and humidity) based on the type of experiment.
Record the load displacement curve and extract key parameters such as maximum load and elongation at break.
data analysis
Compare the standard requirements and determine whether the material is qualified.
Recheck or expand sampling of non-conforming items to ensure the reliability of the results.