Finite Element Analysis Of Tempreture And Stress Field Of External Wall Insulation Bolt

In recent years, domestic buildings usually have adopted the external insulation systems which have numerous advantages out of building insulation and energy-saving. But during the popularization and application of a variety of external insulation technology and products, building metope have been more or less appearing phenomena such as hollowing, deflection, cracks, and shedding, which directly affects energy-saving effect. In order to ensure reliability and security of external insulation system, it is necessary to reinforce it by mechanical anchoring on the basis of bonding fixing. However, anchor bolts also have a negative effect to the external insulation system, such as thermal bridge of anchor bolt and hollowing and cracking surrounding bolt. Therefore, carrying out comprehensive finite element analysis to discuss expansion bolt's thermal bridge effect, temperature deference's impact on the strength of new expansion bolt, as well as hollowing and cracking reasons of external insulation board being anchored, has great significance to application and promotion of expansion bolts and external insulation technology.Using finite element method, the text analyzed the temperature distribution of expansion bolts, hollow bricks, mortar and insulation board under temperature load, then deserved the displacement, strain and stress field through thermal-structure coupling analysis. In addition, the calculation results were tested through corresponding theoretical knowledge. The results showed it is feasible to calculate engineering problems using finite element method.The principle duties include: Deserving system's temperature field distribution anchored by new expansion bolt and not as well as a single bolt's added value of heat transfer to system by comparison on the basis of appropriate simplification and assumptions; Calculating and depicting curves of single bolt's added value of heat transfer to system changed with bolt density and diameter, providing optimal density and diameter of anchor bolt for the engineering application; Analyzing temperature, displacement, strain and stress of system under two kinds of outdoor thermal loads, namely, heating and cooling, deserving that the new expansion bolt meet required strength under thermal stress; Researching on the main cracking reasons of external insulation system, proposing that performance such as elastic modulus, coefficient of expansion of adjacent layer of external insulation wall should change gradually and the flexibility of anti-crack mortar should be improved; Proposing that parameters such as anchor depth of expansion bolt, thickness of insulation board and so on should be designed based on cooling conditions.