Bending Test Study And Theoretical Analysis On The New Sandwich Insulation Board

Integration of prefabricated concrete’s insulation and bearing structure system has a crucial and strategic meaning on the implementation of national strategies,such as One Belt and One Road put forward on Thirteen Five,and reducing construction energy consumption.It is also the only way to achieve construction’s industrialization and diversification.Based on above background and previous research results,the thesis introduces passive building to sandwich construction system,puts forward sandwich insulation board combining insulation and bearing properties,realizes design concept on sandwich board’s insulation and bearing.The thesis compares the different influence that different sandwich materials and board structures have on sandwich board’s basic mechanical property by doing static loading experiments on three different sandwich boards;based on the testing result,further analyses on finite element numerical model by ABARUS,makes comparisons on key parameters’ influence on sandwich board’s mechanical property;using elastic mechanic basic principles,builds new sandwich board’s basic mechanic property index;makes thermomechanical analyses on sandwich boards with different insulation and bearing,and provides its economical thickness in hot summer and cold winter zone.The thesis’ s main content and result include:By making static loading experiments on three sandwich boards with same size,compares and analyses some key parameters’ such as different sandwich materials and board structures effect on their basic mechanical property.It shows that sandwich board goes through elastic phase,cracking phase(also called elastic-plastic phase)and breaking phase.Every sample before breaking has obvious failure characteristic,which belongs to ductile failure;JXB1’s loading capacity enhances a lot than JXB2 and JXB3;there isn’t any horizontal fracture in the upper and lower interface of Polystyrene fiberreinforced concrete sandwich,so the matte side of Polystyrene fiber reinforced concrete sandwich can meet the request of shearing.EPS insulation sandwich board only appears slight horizontal fracture,indicating shearing of binding mortar and steel bar truss can meet the request for utilization;by comparing and analyzing different structure systems of sandwich materials and board,Polystyrene fiber reinforced concrete and steel bar truss’ contribution to ultimate bearing capacity is more obvious than sandwich board,and steel bar truss can inhibit crack extension effectively and enhance sandwich board’s ductility properties.Based on the above test results,considering various constitutive relations of concrete,steel and Polystyrene fiber reinforced concrete,a finite element model is established and its rationality is verified by comparing the teat results;Discussing height of steel bar truss and thickness of sandwich’s effect rule on Polystyrene fiber reinforced concrete sandwich’s mechanical property.The analyses show that with the increase of steel bar truss’ height,sandwich insulation board’s loading capacity and stiffness is slightly improved,but the influence is not obvious;with the increase of sandwich’s thickness,sandwich insulation board’s stiffness is continuous increased,and ultimate bearing capacity is obvious with growth rate up to 25.8% at most,but ductility is also decreased.Thus,the change of sandwich thickness’ effect on insulation board’s mechanical property is more obvious.Analyzing on sandwich board’s deflection in utilized limit status by equivalent board theory and sandwich board theory: First,complicated materials are equivalent to homogeneous materials with various properties,to simplify single-layer model,derivate formula about equivalent board model’s elastic constants and calculate equivalent board model’s deflection in normal utilized limit status using theories of plate bend;as for sandwich board theory,based on Reissner sandwich board theory and considering bending resistance capacity of sandwich board,the formula about sandwich insulation board’s deflection under distributed loads is figured out.Comparing the above deflections calculation value and experimental value,they are more consistent using sandwich board theory and have some reference.Based on passive insulation construction design concept,making analysis on new sandwich insulation board’s thermal property,the result shows that the two sandwich insulation boards put forwardin the thesis have practicability;thus,economical thermal insulation thickness in different sandwich insulation boards in hot summer and cold winter zone comes out.