The Damage Identification Of Wooden Beam Cracks From Ancient Building

Chinese ancient architecture has a glorious history,has made a significant contribution to mankind,is the world’s unique style of building science,is an important historical and cultural heritage.With the development of science and technology and the improvement of people’s living standard,the national quality is constantly increasing,people pay more and more attention to the value of history and culture,but the domestic study on wooden structure is becoming less and less,only a few universities in the minority have wood structure course.This makes the protection and detection of ancient buildings gradually developed into a discipline,such as nondestructive testing technology,damage identification technology,health monitoring technology,etc..However,these detection techniques for ancient buildings have their own shortcomings.Such as they are not efficient and accurate,some of the technical methods only stay in the theoretical stage.In this paper,the different detection techniques are summarized.It also points out the different fields of application,and clarifies the difference of nondestructive testing technology and damage identification technology.A brief introduction is given to the methods of nondestructive testing and damage identification.The single beams damage has been distinguished based on a dynamic test.In the paper,we tested the nondestructive condition beam and other damaged beams.The test used hammer excitation method.We extract the first three natural frequency and vibration mode in DASP software,analyze the relationship between the damage index(natural frequency,displacement mode and curvature mode)and different damage conditions,the frequency ratio index can better identify the damage than the natural frequency and frequency difference index whether it happens,but cannot identify the damage location;displacement modal index cannot identify the damage.curvature mode index can identify the damage and can determine the damage location,but the damage sensitivity is not high enough.Then the beam is simulated by finite element method,increase the damage conditions,the same conclusion in the test was obtained.The results of these three kinds of indexes are not ideal for desiccation crack.These conclusions provide a basis for the identification in the whole structure,and can be used in the future health monitoring system.