CN115270327B - Method for calculating bearing capacity of recombinant bamboo-steel splint bolt connection node - Google Patents
Method for calculating bearing capacity of recombinant bamboo-steel splint bolt connection node Download PDFInfo
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Abstract
The invention discloses a method for calculating the bearing capacity of a recombinant bamboo-steel splint bolted connection under a complex stress state, and an analytical model for calculating the bearing capacity of the recombinant bamboo-steel splint bolted connection is constructed. The main contributions of the present invention include: (1) The method provides a bearing capacity calculation analysis model suitable for 28E-165f recombinant bamboo steel splint bolting under a complex stress state; (2) Gives a density of 1.1g/cm 3 According to the standard value of pin and groove bearing strength in the direction of the longitudinal lines and the transverse lines of the recombined bamboo, and 100.19MPa is uniformly taken as the standard value; (3) Three failure modes of the bolt connection of the recombined bamboo steel clamp plates are provided, namely failure modes Is, IIIm and IV; (4) The resistance component coefficients corresponding to different yield modes are researched and given; (5) Boundary conditions for the occurrence of yield modes IIIm and IV are discussed.
Description
Technical Field
The invention relates to the field of mechanical calculation, in particular to a method for calculating the bearing capacity of a bolt connection node of a recombined bamboo-steel splint.
Background
The connection is the most critical part of the application of the recombined bamboo to the structural system bearing member, and the current research on the bolt connection of the recombined bamboo is mainly focused on two kinds of bolt connection of steel clamping plates and bolt connection of steel filling plates. The steel filling plate has attractive bolt connection, but smaller out-of-plane rigidity, and the steel clamping plate has convenient bolt connection construction, larger out-of-plane rigidity and wide application. The most critical problem is that a method for calculating the bearing capacity of the bolt connection of the recombination component and the steel clamping plate in a complex stress state is not found at present, and a bearing capacity analysis model of the connection is mostly explored based on the calculation theory and the method of the bolt connection in a wood structure in the research process. The analysis model for calculating the bearing capacity of the bolt connection of the wood component and the steel clamping plate, which is given by the wood structure design standard (GB 50005-2017), is difficult to be applied to the calculation of the bearing capacity of the bolt connection of the recombined bamboo and the steel clamping plate under the complex stress state, and the main reason is that: 1) The physical and mechanical properties of the recombined bamboo and the wooden product are greatly different; 2) The calculation and analysis model of the bearing capacity of the wood component-steel clamping plate bolt connection is constructed based on a unidirectional stress mode (the direction of the parallel lines or the transverse lines), and the calculation method of the bearing capacity of the connection under the working condition of complex stress connection (bearing the external force in the direction of the parallel lines and the transverse lines at the same time) is further perfected.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a method for calculating the bearing capacity of a bolt connection node of a recombinant bamboo-steel splint.
In order to achieve the aim of the invention, the invention adopts the following technical scheme:
a method for calculating the bearing capacity of a recombinant bamboo-steel splint bolt connection node comprises the following steps:
s1, determining a recombined bamboo node yield mode according to a wood structure bolting bearing capacity calculation theory, and deducing pin-groove bearing effective length coefficients under various node connection yield modes according to stress balance;
s2, calculating the node bearing capacity according to the determined node yield mode, and comparing the calculated node bearing capacity result with a finite element model simulation result by adopting a reasonable recombined bamboo steel splint bolt connection node finite element model;
and S3, correcting and verifying a node bearing capacity calculation mode according to the node bearing capacity result compared in the step S2 and the finite element model simulation result, and outputting a node design of the steel splint bolt node.
Further, the node yield mode in S1 comprises a restructured bamboo pin groove bearing damage I s Single hinge yielding III of bolt in recombined bamboo board m The bolt is arranged at the interface of the recombined bamboo board and the steel boardDouble hinge yield IV occurs.
Further, the calculating mode of the effective length coefficient of the pin groove bearing in the S1 is as follows:
K aⅠ ＝0.5
wherein K is aⅠ 、K aⅢ 、K aⅣ Respectively the node yield modes comprise the restructured bamboo pin groove bearing damage I s Single hinge yielding III of bolt in recombined bamboo board m And bolt bearing effective length coefficient a of double-hinge yield IV of bolt at interface of recombined bamboo board and steel board 0 The effective bearing length of the wood pin groove is; f (f) ha Is the standard value f of the bearing strength of the pin groove of the wood ha Is the standard value M of pin groove bearing strength of the recombined bamboo component y Is the yield bending moment of the bolt, d is the pin diameter, eta is the pin diameter ratio, eta = a/d, and a is the wood member thickness; f (f) y The yield strength standard value of the round steel pin; k (k) ep Is an elastoplastic strengthening coefficient.
Further, the finite element model determination node yield mode judgment standard in the step S1 is as follows: when the bamboo board hole is deformed for 0.05d, the pin groove bearing damage I occurs s The method comprises the steps of carrying out a first treatment on the surface of the If the displacement of the bamboo plate holes is not destroyed but the bolts yield, a IIIm or IV destruction mode is considered to occur, wherein when the bolts generate single hinge yield III in the recombined bamboo plate m A single hinge is formed in the bamboo board during the damage, and double hinges are formed in the recombined bamboo board and the junction of the recombined bamboo and the steel plate when the double hinge yield IV damage occurs at the junction of the recombined bamboo board and the steel plate by the bolt.
Furthermore, the establishing mode of the finite element model of the bolt connection node of the recombinant bamboo steel splint in the S2 is as follows:
based on a multi-fold model of pin-slot compression and pin bending stress-strain, a sign that the plastic deformation of 0.05d is generated by connection reaches the limit state of bearing capacity
Further, the formula of the bolt connection bearing capacity of the bamboo steel clamping plates after the correction in the step S3 is expressed as follows:
R k ＝K ad,min adf ha
K aⅠ ＝0.5
wherein R is k The standard value of the bearing capacity of the single bolt;for adjusting the coefficients, the adjustment coefficients are taken according to the test advice +.>1.5.
Further, the specific mode of the node design of the output steel splint bolt node in the step S3 is as follows:
s31, preliminarily selecting a bolt with the diameter d, and determining the single-bolt bearing capacity R of the bolt according to a bearing capacity analysis model k ；
S32, determining the number of bolts according to a stress formula and setting the arrangement form of the bolts on the basis of meeting the construction requirement;
s33, judging whether the stress resultant force of the bolts at the upper edge of the corner is smaller than or equal to the single bolt bearing force, and if so, outputting the determined diameter, number and arrangement form of the bolts;
s34, if the stress resultant force of the bolts at the upper edge of the corner is larger than the Shan Shuanzhu bearing force, judging whether the number of the bolts is consistent, if not, re-determining the number of the bolts and replacing the arrangement form, and if so, re-arranging the arrangement form
The invention has the following beneficial effects:
1. the method provides a bearing capacity calculation analysis model suitable for 28E-165f recombinant bamboo steel splint bolting under a complex stress state;
2. the density of 1.1g/cm was described based on the existing test data using a lognormal distribution model 3 According to the recombined bamboo longitudinal and transverse line directions, and 100.19MPa (confidence level 75% and quantile 0.05) is uniformly taken as the pin groove bearing strength standard value;
3. three damage modes of the bolt connection of the recombined bamboo steel splints are provided, namely, the wall of the recombined bamboo splints is subjected to pressure-bearing damage I s The pin forms a plastic hinge III in the recombined bamboo board m And the pin respectively forms two plastic hinges IV in the bamboo boards and between the steel clamping boards and the recombined bamboo boards;
4. the resistance component coefficients corresponding to different yield modes are researched and given;
5. discussing yield pattern III m And boundary conditions present in IV.
Drawings
FIG. 1 is a flow chart of a method for calculating the bearing capacity of a bolt connection node of a recombinant bamboo-steel splint according to the present invention.
FIG. 2 is a schematic diagram of a bolt node design flow according to the present invention.
FIG. 3 shows the yield pattern of the double shear connection of the steel splints pin connection of the embodiment of the invention, wherein a is I m Disruption, b is III m And c is IV.
FIG. 4 shows the distribution of compressive stress in a bolted joint according to an embodiment of the invention, wherein a is I m Disruption, b is III m And c is IV.
Figure 5 is a graph of yield versus limit load determination load-deflection for an embodiment of the present invention.
Fig. 6 is a stress cloud of 96-16-10 nodes according to the embodiment of the invention, wherein a is a recombinant bamboo stress cloud, and b is a bolt stress cloud.
FIG. 7 is a diagram illustrating the forces of the group bolt under the action of axial force and bending moment according to an embodiment of the present invention.
Fig. 8 is a schematic view showing an arrangement of a bolt node according to an embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention is provided to facilitate understanding of the present invention by those skilled in the art, but it should be understood that the present invention is not limited to the scope of the embodiments, and all the inventions which make use of the inventive concept are protected by the spirit and scope of the present invention as defined and defined in the appended claims to those skilled in the art.
A method for calculating the bearing capacity of a recombinant bamboo-steel splint bolt connection node is shown in fig. 1, and comprises the following steps:
s1, determining a node yield mode according to a recombinant bamboo bolting bearing capacity calculation formula, and calculating a pin groove bearing effective length coefficient in each middle node yield mode;
specifically, in this embodiment, it can be seen that, in combination with the bearing capacity calculation formula of the european wood structural design specification and the current GB5005-2017 "wood structural design standard", it is shown that: 1) If I occurs m When broken, the diameter of the pin is thick, the middle component is thinner, the side component is thicker, and the pin groove of the middle component is extruded and broken. 2) I s The diameter of the pin is thick, the middle component is thick, the side component is thin, and the pin groove of the side component is extruded and broken. 3) III m The diameter of the pin is smaller, the bearing strength of pin grooves of the two members is the same, and plastic single hinge appears in the middle member; 4) The diameter of the IV pin is smaller, the bearing strength of pin grooves of the two members is higher, and plastic double hinges appear in the two members. When a bolt yield failure occurs, whether single-hinge or double-hinge failure, it is believed that the bolt yields to failure when the joint plastically deforms to 0.05d according to the European yield mode.
When the steel splints are connected in double shearing, the rigidity of the steel plate is obviously higher, so the pin groove bearing strength of the steel plate is higher than that of the recombined bamboo for the four yield modes, and three damage modes are considered to be shown in figure 3 without considering that the steel plate reaches the pin groove bearing strength.
FIG. 4 represents failure mode I s 、Ⅲ m Failure mode I s The wall of the connecting recombinant bamboo board hole is damaged under pressure; III m The pin forms a plastic hinge inside the recombined bamboo board; IV pin forms two plastic hinges in the bamboo board and between the steel clamping board and the recombined bamboo board,
the stress balance conditions according to fig. 4 (a), (b) and (c) result in formulas (1), (2) and (3):
wherein: m is M y Is the yield bending moment of the bolt, M y ＝f y k w πd 3 /32；f y Is the standard value of the yield strength, k of a round steel pin w Is the plastic coefficient, k is when completely plastic w =1.7; d is the diameter; a, a 0 The effective bearing length of the wood pin groove is; f (f) ha Is the standard value of the pin-slot bearing strength of the wood.
At this time, the bearing capacity R of the single shear surface obtained by the stress balance is respectively (4), (5), (6) and the effective length coefficient K of pin groove bearing aⅠ 、K aⅢ 、K aⅣ See formulas (7), (8), (9):
R＝K aⅠ adf ha (4)
K aⅠ ＝0.5 (7)
according to GB50005-2017 wood design standards [3] For III m Taking k from IV destructive form w Yield mode iii =1.4 m The effective length coefficients of pin groove bearing corresponding to the IV are (10) and (11):
wherein: f (f) ha The standard value of the pin groove bearing strength of the wood component is obtained; η is the pin diameter ratio, η=a/d, d is the pin diameter, a is the wood member thickness; f (f) y The yield strength standard value of the round steel pin; k (k) ep Is an elastoplastic strengthening coefficient.
R k ＝K ad,min adf ha (12)
Wherein: k (K) ad,min Coefficients are calculated for the bearing capacity design values.
To maintain the reliability of the bolt connection design to be basically consistent with CB5005-2003, the existing 4 kinds of bamboo species recombined bamboos with known air-drying mass density and yield mode I are statistically analyzed s The bearing capacity of the corresponding bolted connection is shown in table 1. The design value of the bearing capacity of the bolt connection in the table is R a ＝0.7adf c Calculation (f) c Is the cis-grain compressive strength of wood). The standard value of bearing capacity is R in CB5005-2017 d ＝K ad,min adf ha Calculating, wherein the bearing strength is calculated according to f ha =77G calculation. Coefficient of resistance component gamma I ＝R k /R d . Thereby obtaining the resistance component coefficient to obtain gamma I 1.56, the wood structure takes the value gamma I 4.38. It can be seen that the subentry coefficient of the recombined bamboo is 1.8 times lower than that of wood.
TABLE 1 calibration of bearing capacity for bolt-on yield mode is
In the table: r is R k Designing a value for the bearing capacity calculated according to GB 5005-2017; r is R d The bearing capacity calculated according to GB 5005-2003 is designed.
Similar failure mode I s Corresponding resistance component coefficient gamma I Statistical analysis of 4 recombinant bamboo products known air-dried density recombinant bamboo, bolt connection and yield mode III m The results of the corresponding bearing capacities of IV are shown in Table 2. R in the table k R is calculated according to formulas (14), (15) (16), (17) d Calculated according to equation (17). The ratio of the two is the resistance component coefficient. The bolt adopts steel material Q235, k ep =1.0. As is clear from the foregoing, the fracture mode is different depending on the thickness-to-diameter ratio (a/d), and the fracture mode gradually changes from III as the thickness-to-diameter ratio increases m And IV is developed, so that the thickness-diameter ratio needs to be considered for the value of the subentry coefficient. Since the ratio of thick to thick is one, no bolt bending failure occurs, and thus it is considered to start from a/d=2. Therefore, the recombined bamboo can take gamma Ⅲ 、γ Ⅳ 1.28, compared with wood Ⅲm ＝2.22、γ Ⅳ ＝1.88。
R k ＝K ad,min adf ha (14)
TABLE 2 bolting yield pattern III m IV bearing capacity calibration
Note that: the diameter of the bolts in the table is 16mm, and the bearing strength of the bamboo pin grooves is the same as that of the upper table.
The bearing capacity design value calculation formulas of the single shear surface of the single pin can be obtained by determining the corresponding bolting resistance component coefficients of each yield mode, wherein the formulas are shown as formulas (18) and (19):
R d ＝K ad,min adf ha (18)
when the bearing capacity of the bolt connection of the bamboo structure is explored, the bearing strength of the pin groove has important significance. Acquisition of Pin-groove bearing Strength according to ASTM D5764-97a [6] The single bolt axial compression test is carried out by the specified test method, firstly, the load-displacement curve obtained by the test of the bearing yield load of the groove is determined as shown in figure 5, namely, after the maximum load, the maximum load on the load-displacement curve is taken as the yield load at the intersection point of the pin taking groove plastic deformation. The yield load divided by the bolt diameter and the bamboo panel thickness is the pin load strength.
The standard value of the bearing pressure of the pin slot is specified in the current wood structure design standard of China GB50005-2017 as follows: when 6mm<d<25mm, the pin groove following grain bearing strength F of the pin shaft type fastener e,0 Should be determined as Fe, 0=77G. Studies have shown that both design formulas in NDS/LRFD and Eurocode are based on lower density wood (0.36～0.52g/cm 3 ) Trial use of high density wood is not considered. Two design formulas were used at a density of 0.70g/cm 3 And the left and right wood pin groove bearing strength is predicted, and the result is found to be smaller. The degree of prediction for pin and groove bearing strength values is too conservative. Therefore, statistics of pin and groove bearing strength values of the recombined bamboo (with mechanical property strength grade of 28E-165 f) for the structure manufactured by taking the Sagittaria sagittifolia as a raw material are shown in Table 3.
Table 3 results of the recombinant bamboo pin groove pressure test
S2, calculating the node bearing capacity according to the determined node yield mode, establishing a recombined bamboo steel splint bolt connection node finite element model, and simulating and comparing the calculated node bearing capacity result with a finite element model simulation result;
according to the yield mode, the connection is made with a sign that plastic deformation of 0.05d (d is the pin diameter) reaches the load-bearing capacity limit state, based on a steel plastic model of pin slot bearing and pin bending stress-strain. The calculation formula of the bearing capacity of the recombined bamboo single bolt with the strength grade of 28E-165f is deduced, so that the bearing capacity of the single bolt in the finite element needs to be compared. For the integral model, the load applied to the bolts is consistent with the shearing force of the surface of the bamboo board hole. Therefore, the load born by the single bolt in the process of damage, namely the bearing capacity, can be obtained through the resultant force of all nodes on the surface of the bamboo plate hole. Finite element results are given here for failure mode I s 、Ⅲ m The corresponding discriminant criteria of IV are respectively: when the deformation of the bamboo board hole is 0.05d, the pin groove is considered to be damaged under pressure, namely the damage mode is I s . If the displacement of the bamboo plate holes does not reach the damage, but the bolts yield, the damage mode of IIIm or IV is considered to occur. According to the damage state, the concurrent occurrenceRaw III m When broken, a single hinge is formed in the bamboo board. When IV damage occurs, double hinges are formed at the junction of the recombined bamboo board and the steel board. After loading to failure, entering post-processing to check the deformation result of the bolt: taking half of the bolt member and selecting the total displacement of the bolt at the positions of the outer surface (z=a/2+c) of the steel plate, the interface (z=a/2) of the recombined bamboo plate and the steel plate, the cross section (z=a/4) and the center (z=0) of the bolt, and calculating the slope size according to the relative displacement value. If the slope of the bolt in the bamboo board is increased firstly and the slope at the interface of the recombined bamboo board and the steel board is unchanged, the single hinge damage is considered to occur. If the slope at the interface of the recombined bamboo board and the steel board is smaller, double-hinge damage is considered to occur, namely the steel board has a certain clamping effect on the bolt.
The vertical load loading position is in the center of the steel hub and is not axially stressed for the bolts. Therefore, the stress is required to be formed by the combined action of shearing force and bending moment. When the load is loaded to 330KN, the stress of the recombined bamboo board reaches, the stress cloud diagram of the bolts and the bamboo board is shown in fig. 6, the stress of the bolts locally exceeds the bearing strength of the pin grooves by 111MPa, the stress of the recombined bamboo board holes is between 60 and 120MPa, and at the moment, the bolts are bent to a large extent and the large area exceeds the yield stress by 640MPa to enter a yield state.
At this time, the bolts were considered to undergo hinge yield failure, and the bearing capacity finite element results corresponding to each bolt were extracted as shown in table 4.
Table 4 single bolt bearing capacity
From the above table, the above graph is as follows: the bolts with the numbers of 1-1, 2-3, 2-4, 3-2, 4-3, 4-4 and the maximum bearing capacity on each bolt reach 74kN, the corresponding deformation of each bolt is extracted on the basis, the interface (z=a/2) between the recombined bamboo board and the steel plate, the section position in the bamboo board and the bolt deformation and the slope of the center (z=0) of the bamboo board are calculated, and the calculation results are shown in the following table 5:
table 5 summary of bolt node displacement
From the above results, it can be found that the deformation slope of the bolt in the present configuration is gradually increased, i.e., no clamping action is generated on the bolt at the steel plate, according to the judgment criterion that the finite element analysis given above reaches the failure. However, if the slope of the bolts 4-3 is reduced at the positions of the steel plate and the bamboo plate, the damage mode of the bolt joint of the recombined bamboo steel splint is regarded as III m And IV, calculating to obtain the bearing capacity of the recombinant bamboo bolting node under the structure according to a calculation formula corresponding to the damage mode deduced by the previous step, and according to III m The mode calculation bearing capacity is 38.705MPa, the bearing capacity is 54.737MPa according to the IV mode calculation bearing capacity, and the bearing capacity on a single bolt is up to 74.601MPa, so that the calculation formula of the wood structure bolt connection bearing capacity is not suitable for the calculation of the recombinant bamboo steel splint bolt bearing capacity. Thus, analysis of the above formula can find that k is w The value of (2) represents the plastic development coefficient, so that the strength of the recombined bamboo is higher than that of the wood, the plastic development degree of the bolt is higher, and k is calculated ep Represents the elastic-plastic strengthening coefficient, k of the round steel pin w The value of (2) represents the plastic development coefficient. Thus for k ep And k w And the value of (2) is adjusted. Considering the complete plastic development of round steel pins, the standard bending moment value M y ＝f y k w πd 3 /32, where k w =1.7. In the calculation of the pin connection in China, the plasticity is considered to be insufficiently developed, and k is taken w =1.4. The design specification of the wood structure in China adopts the elastoplasticity coefficient to reflect the influence of the material characteristics of the steel pins to the connection bearing capacity, and the steel material of the common Q235 accords with the rational elastoplasticity assumption and takes k ep =1.0; NDS-2005 takes the strengthening property of steel into consideration, and takes k ep =1.3. Is adopted in k ep And k w Values 1.3 and 1.7 respectively according to III m The mode calculation bearing capacity is 48.630MPa, and the bearing capacity is 68.773MPa according to the IV mode calculation. Visible recombined bamboo snailThe coefficient consideration of the steel splints connection node with reference to NDS-2005 is more reasonable.
And S3, correcting and verifying a node bearing capacity calculation mode according to the node bearing capacity result compared in the step S2 and the finite element model simulation result, and outputting a node design of the steel splint bolt node.
According to the bearing capacity formula analysis of the wood structure of GB50005-2017 wood structure design standard, the influence factors of the bearing capacity design value relate to the thickness of the recombined bamboo board, the diameter of the bolt and the thickness of the steel plate. Therefore, the influence of the thickness factors of the recombined bamboo boards, the diameters of the bolts and the thickness factors of the steel plates on the bearing capacity needs to be studied respectively. Therefore, a reasonable calculation formula suitable for calculating the bolt connection bearing capacity of the recombined bamboo steel splints is given based on the bolt connection formula of the wood structure steel splints. First of all in combination with the European yield mode, I occurs s The diameter of the pin is thick, the middle component is thin, the steel plate at the edge is thick, and the pin groove of the middle component is extruded and damaged. When III occurs m The diameter of the pin is smaller during the damage, the bearing strength of pin grooves of the two members is the same, and plastic single hinge appears in the middle member; when IV is damaged, the diameter of the pin is smaller, the bearing strength of pin grooves of the two components is higher, and plastic double hinges appear in the two components. The three failure modes can be used for finding out that node failure is mainly divided into two cases of bearing yield of pin grooves of the bamboo board and yielding of bolts. When the thickness of the bamboo board is thinner, the rigidity and the strength cannot resist the external load effect, and the local buckling of the hole wall occurs; when the thickness of the bamboo board reaches a certain degree and the diameter of the bolt is smaller, the yield of the bolt occurs at the moment. The bolt yields and is divided into a single-hinge yield mode and a double-hinge yield mode, and the strength and rigidity of the steel plate and the bolt influence the formation of the single hinge and the double hinge through analysis of the European yield mode. In combination with European Specification EC5, the steel plate is divided into a thin steel plate and a thick steel plate, and it is considered that the thin steel plate has no clamping effect on the bolts, and the thick steel plate has clamping effect on the bolts, thereby forming a plastic double hinge [2] . Then, failure mode III for single and double hinge formation m And IV should be related to the strength of the selected steel plate and bolt. Thus, the analysis can be performed qualitatively: when the bolt strength is low, the diameter is thin, and the steelWhen the strength of the plate is high, the bolt is easy to clamp, so that the bolt forms a double hinge at the interface of the bamboo plate and the bolt; when the bolt strength is high or the bolt diameter is thick, but the steel plate thickness is low, the clamping effect cannot be generated on the bolt, and then the steel plate thickness cannot be used for clamping the bolt. Therefore, whether or not the steel plate will act as a clamp on the bolt depends on the relative strength and rigidity of the two. The thickness of the steel plate only affects the single-hinge or double-hinge damage of the bolt when the strength of the bolt is equal to that of the steel plate. According to the steel structure design standard, the general types of the steel plates and the general types of bolts which are commonly applied to the market at present are shown in the table 6 and the table 7 respectively.
Table 6 common Steel plate number
Table 7 common bolt rating
The bolts adopted in the test are 8.8-level high-strength bolts, and the steel plate strength is Q235 steel. The impact analysis on the bearing capacity is established in the test, the brand of steel is Q235, and the grade of the bolt is 8.8 grades of the pressure-bearing high-strength bolt. From the above analysis, it can be seen that the bolts used in the test are of higher grade, while the steel grade and strength are lower. This will have an effect on the boundaries of the different failure modes.
When the thickness of the recombined bamboo member is thinner, the recombined bamboo member is similar to the phenomenon that wood is easy to crack, brittle failure and the like. Such damage is a brittle failure and is often not allowed to occur. Meanwhile, according to a bearing capacity calculation formula, the thickness of the recombined bamboo member has an important influence on the bearing capacity. When the thickness of the bamboo member is thinner in combination with the yield mode, the calculation result proves that in the process of changing the bamboo plate from 32mm to 64mm, the bolts are 8.8-level high-strength bolts with the diameter of 16mm, the rigidity of the bolts is higher, and I is easy to occur s The pin grooves of the bamboo boards are damaged under pressure. When the bamboo board reachesWhen the rigidity of the bamboo component is enough to resist the bending of the bolt at a certain thickness, the bolt yields before the bamboo board, namely the failure mode is changed into III m Or a type iv failure mode. At this time, the thickness of the bamboo board is no longer used as a factor for controlling the damage mode.
Through the analysis of different thicknesses of the bamboo boards, the bearing capacities of the bamboo boards with the thicknesses of 25mm, 32mm and 48mm and the corresponding diameters of the bolts and the thicknesses of the steel plates are set, and the calculation results are listed in the following table 8
Table 8 comparison of bearing damage and bearing capacity calculation of bamboo plate pin groove
Wherein: p (P) t Calculating a result for a bearing capacity formula; p (P) c Results are calculated for the finite elements.
For the bearing damage of the pin slot of the bamboo board, namely the yield mode is I s The corresponding finite element analog value is basically consistent with the calculated value, C t The average value of (C) is 1.068, and the mode of bolt connection yield of the recombined bamboo steel splint is regarded as I s The bearing capacity calculation formula is consistent with the wood structure bolt connection bearing capacity calculation formula.
The thickness of the steel sheet determines the failure mode of the node and the corresponding load bearing capacity calculation. When the thickness of the steel sheet is less than 0.5d, the steel sheet is a thin steel sheet. When the thickness of the steel plate is greater than d and the pore diameter tolerance is less than 0.1d, the steel plate is a thick steel plate. In order to find out whether the thickness of the steel plate of the connecting node of the recombined bamboo steel splint is the same as that of the bamboo plate, the thickness of the steel plate is 0.5d-d, and finite element simulation is performed by unifying the diameters of bolts of bamboo members with the same thickness. When the thickness of the lower bamboo component is 64mm, in order to avoid the bearing damage of the pin grooves of the steel plate, when the diameter of the bolt is 8mm, the minimum thickness of the steel plate is 6mm; when the diameter of the bolt is 10mm, the minimum thickness of the steel plate is 12mm; when the bolt diameter is 12mm, the minimum thickness of the steel plate is 16mm. The bearing capacities of the different bolt diameters of 8mm,10mm and 12mm and the different steel plate thicknesses were calculated, and the results were counted in the following table 10. Considering that the bolt plasticity development coefficient in the bamboo board is higher, the calculation formula is calculatedMiddle pair k ep And k w Carrying out different values and substituting into a bearing capacity calculation formula to calculate the bearing capacity, and introducing a check coefficient C t 。
The bearing capacity of the bolt connection node of the recombined bamboo steel splint is far higher than that of the bolt connection node of the wood structure steel splint, so that the ratio of the finite element calculation result of the single bolt to the theoretical calculation result is introduced as the bamboo-wood strength performance scale factor C t The average value of the thickness ratio of 64mm was 1.77. When the thickness of the bamboo board is 64mm, when the diameter of the bolt is 8mm and the thickness of the steel plate is 6mm, the bolt III occurs m Failure mode, IV failure mode occurred when 8-16 mm. When the bolt diameter is 10 and 12mm, the steel plate will not be able to clamp the bolt.
The average value of the thickness ratio of 90mm was 1.83. When the thickness of the bamboo board is 90mm, the IV failure mode of the bolt occurs when the diameter of the bolt is 8 mm. When the bolt diameter is 10 and 12mm, the steel plate will not be able to clamp the bolt. The statistics of the calculation results are shown in Table 9, which are the same as those when the thickness of the bamboo board is 64 mm.
Statistics of different bolt diameters and steel plate thicknesses of 90mm thick bamboo plates
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The average value of the thickness ratio of 120mm was 1.86. When the thickness of the bamboo board is 120mm, the IV failure mode of the bolt occurs when the diameter of the bolt is 8 mm. When the bolt diameter is 10 and 12mm, the steel plate will not be able to clamp the bolt. The calculation results are shown in Table 10, which are the same as those when the thickness of the bamboo board is 64 mm.
Table 10 statistics of different bolt diameters and steel plate thicknesses of 120mm thick bamboo plates
Since only the three yield modes are considered according to the yield mode, the pin and groove bearing damage of the steel plate is avoided, and the pin and groove bearing strength of the steel plate needs to be checked according to the formula (20) in the steel structure design Specification GB 50017-2017. The bolts adopted in the test are 8.8-level pressure-bearing high-strength bolts, and the steel plate strength is Q235 steel. The searching standard shows that the pin groove bearing strength of the Q235 steel and the 8.8-grade bearing high-strength bolt is 470MPa. Therefore, in the comparison working condition of the thickness of the steel plate and the diameter of the bolt, the minimum value of the thickness of the steel plate is determined according to the method. Ensuring that the steel plate is not damaged before the bolts and avoiding the bearing form of the pin grooves of the steel plate
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Wherein:the pin groove bearing strength of the steel plate. The value of this test is 470MPa.
The bolt connection node failure mode and the corresponding bearing capacity calculation formula proposed by the wood structure design specification are based on Johanson yield theory, and the steel plate is divided into a thin steel plate and a thick steel plate. It is considered that the thick steel plate has a clamping effect of a bamboo structure for rotation of the bolt, and the thin steel plate has no remarkable restraining force. The thickness of the steel sheet thus determines the failure mode of the node and the corresponding load bearing capacity calculation. When the thickness of the steel sheet is less than 0.5d, the steel sheet is a thin steel sheet. When the thickness of the steel plate is greater than d and the pore diameter tolerance is less than 0.1d, the steel plate is a thick steel plate. Since the steel grade is Q235, the bolt can be clamped only when a certain thickness is reached. Similarly, the starting end of the linear section of the bearing capacity change at the time of the bolt diameter of 8mm,10mm,12mm is approximately regarded as the limit of the bolt steel sheet, so the limit of the steel sheet is the critical steel sheet thickness at which the pin groove bearing damage occurs in the steel sheet without the pin groove bearing damage occurring in the bamboo sheet, and the steel sheet thickness is regarded as the thick steel sheet when it reaches 1.4 times d. From the comparison of the results, the yield mode of the recombined bamboo steel splint bolting node is slightly different from that of the wood component, and the bearing capacity of the recombined bamboo steel splint bolting node is higher than that of the wood structure bolting node. Therefore, mu is introduced into the bolt connection node of the recombined bamboo steel splint, the average value of the mu is 1.8 through analysis, and the corrected bolt connection bearing capacity formula of the recombined bamboo steel splint is expressed as follows:
R k ＝K ad,min adf ha (21)
wherein: μ is determined from the finite element calculations previously described.
Because all the working conditions are the bearing capacity on the single bolt when the node is damaged, and the bearing capacity calculation formula considers that the bearing capacity is achieved when the bolt reaches yield. Therefore, the coefficient is introduced into the calculated value, the coefficient is that the stress on the bolt reaches 780MPa when the bolt is damaged, and the yield stress of the bolt is 640MPa, so that the bearing capacity calculation result is introduced into the reduction coefficient gamma, and the value is the ratio of the limit stress to the yield stress, namely the value is 0.8.For adjusting the coefficient->Therefore, the single shear face bearing capacity calculation formulas of the single bolt are shown as formulas (23), (24), (25), (26) and (27):
R k ＝K ad,min adf ha (23)
K aⅠ ＝0.5 (25)
wherein: gamma is the ratio of the limit stress to the yield stress, and the value is 0.8.
To verify the applicability of the formula, the adjustment coefficient is takenThe test results of the recombinant bamboo steel splint bolted joint were calculated at 1.5 and are shown in table 11 below for comparison with the test results thereof.
Table 11 comparison of the results and calculated values of the single bolt connection recombinant bamboo carrying performance of the steel splint
Wherein: pt is the bearing capacity calculation result, and Pc is the bearing capacity result of the node tested by the test.
From the upper scale factor C t Since the average value of (2) is 1.4, since interpolation is not performed if the unyielding pattern is at the boundary of the thin steel plate, a certain deviation is allowed. Secondly, as the experimental study of Li Xiazhen adopts the recombined bamboo material taking moso bamboo as the raw material, the grain-oriented compressive strength of the recombined bamboo material is far lower than that of the recombined bamboo material in the experiment, so that the bearing capacity calculation formula proposed in the section is not completely limited by the strength grade and the types of the recombined bamboo materials, the method can be suitable for the bearing capacity of the bolt connection nodes of the recombined bamboo materials of different varieties, and the correctness of the method still needs to be verified and corrected through more experiments and finite element calculation analysis in the later period.
The node design flow is shown in fig. 2, and specifically includes:
s31, preliminarily selecting a bolt with the diameter d, and determining Shan Shuanzhu bearing capacity R of the bolt according to a bearing capacity analysis model k ；
S32, determining the number of the studs according to a stress formula and setting the arrangement form of the studs on the basis of meeting the construction requirement;
s33, judging whether the stress resultant force of the bolts at the upper edge of the corner is smaller than or equal to the bearing force of a single bolt, and if so, outputting the determined diameter, number and arrangement form of the bolts;
and S34, if the combined force of the stress of the bolts at the upper edge of the corner is larger than the Shan Shuanzhu bearing force, judging whether the number of the bolts is consistent, if not, re-determining the number of the bolts and replacing the arrangement form, and if so, re-arranging the arrangement form.
According to the calculation method of the steel structure bolt connection form, the rotation center is approximately considered to be the centroid of the bolt group. Because the shearing force is smaller at this time, the joint stress under the combined action of the axial force and the bending moment is considered, as shown in fig. 7, the bolt group is subjected to the combined action of the shearing force and the torque at this time, and the stress form can be split into the combination of only the shearing force and only the torque.
Under the action of shearing force F passing through the centroid of the bolt group, each bolt is considered to be uniformly stressed, and the corresponding stress is shown in a formula (28).
The group of bolts is under torque, each bolt being actually sheared. The calculation assumes that the connecting member is absolutely rigid and the bolts are elastic, so that the bolts are all rotated about the centroid of the bolt group, the magnitude of the force being proportional to the distance from the centroid of the bolt group, the direction being perpendicular to the line connecting the bolts to the centroid. Let the distance between the bolts 1,2, …, n and the centroid of the bolt group be r 1 ，r 2 ，…,r n The force born by each bolt is N respectively 1F ，N 2F ，…， N nF . The torque may be expressed as formula (29) according to the equilibrium condition.
T＝N 1T r 1 +N 2T r 2 +…+N nT r n (29)
Considering that the stress of the bolt is proportional to the distance between the centers of the bolts under the action of torque, the formula (1-30) is given. Still further, bringing equation (30) into equation (29) yields equation (31), and the stress at the upper edge of the corner can be decomposed into equations (32) and (33).
As can be seen from FIG. 7, the bolts at the upper edges of the corners are furthest from the centroid and are most stressed, and the resultant force is
In the design of the joint, the bolt with the greatest stress must satisfy the formula (36), and the bearing capacity should be calculated according to the formulas (37) and (38).
R d ＝K ad,min adf ha (37)
Wherein: f is the axial force, n is the number of bolts, and Rk is the standard value of the single shear face bearing capacity of a single bolt.
Therefore, the node of the lattice shell structure with the span of 4m is designed by taking the lattice shell structure as an example (the recombined bamboo has the cross section size of 50mm multiplied by 100mm and the thickness of the steel plate is 10 mm). Firstly, calculating according to the single shearing face bearing capacity calculation formulas (23) - (27) of 1.4 sections of single bolts to obtain the bearing capacity of the 8.8-stage bolts with the diameter of 8mm as 82.43kN; secondly, according to the shearing force of 77.209kN and a formula (35), 8 bolts are initially selected; then, based on the construction requirement, 4 bolts are planned to be distributed at equal intervals (with equal distance between x and y) around the centroid in 2 rows and 2 columns, and the distance between the bolts and the centroid r is 40mm; finally, according to the torque of 8.716 kN.m, the torque is brought into a formula (36), and N1 is 69.48kN, so that the torque meets the requirements. The diameter, number and arrangement of bolts in the final bolt joint are shown in fig. 8.
In this embodiment, the load-bearing capacity formula of the recombined bamboo steel splint bolt connection is applied to the node design of the steel splint bolt node, and for different stress forms, the method similar to the method of the steel structure group bolt action node design is utilized to make the resultant force born by each bolt smaller than or equal to the load-bearing capacity born by a single bolt. It is worth noting that the bending moment in stress should meet the structural requirement first, the node is designed based on the fact that at least two bolts are selected for the node to resist the bending moment.
The principles and embodiments of the present invention have been described in detail with reference to specific examples, which are provided to facilitate understanding of the method and core ideas of the present invention; meanwhile, as those skilled in the art will have variations in the specific embodiments and application scope in accordance with the ideas of the present invention, the present description should not be construed as limiting the present invention in view of the above.
Those of ordinary skill in the art will recognize that the embodiments described herein are for the purpose of aiding the reader in understanding the principles of the present invention and should be understood that the scope of the invention is not limited to such specific statements and embodiments. Those of ordinary skill in the art can make various other specific modifications and combinations from the teachings of the present disclosure without departing from the spirit thereof, and such modifications and combinations remain within the scope of the present disclosure.
Claims (3)
1. The method for calculating the bearing capacity of the recombinant bamboo-steel splint bolt connection node is characterized by comprising the following steps of:
s1, determining a recombined bamboo node yield mode according to a wood structure bolting bearing capacity calculation theory, and deducing effective length coefficients of pin groove bearing under various node connection yield modes according to stress balance, wherein the effective length coefficients of the pin groove bearing are calculated in the following way:
K aⅠ ＝0.5
wherein K is aⅠ 、K aⅢ 、K aⅣ Respectively the node yield modes comprise the restructured bamboo pin groove bearing damage I s Single hinge yielding III of bolt in recombined bamboo board m And bolt bearing effective length coefficient a of double-hinge yield IV of bolt at interface of recombined bamboo board and steel board 0 The effective bearing length of the wood pin groove is; f (f) ha Is the standard value f of the bearing strength of the pin groove of the wood ha Is the standard value M of pin groove bearing strength of the recombined bamboo component y Is the yield bending moment of the bolt, d is the pin diameter, eta is the pin diameter ratio, eta = a/d, and a is the wood member thickness; f (f) y The yield strength standard value of the round steel pin; k (k) ep Is an elastoplastic strengthening coefficient;
s2, calculating the node bearing capacity according to the determined node yield mode, and comparing the calculated node bearing capacity result with a finite element model simulation result by adopting a reasonable recombined bamboo steel splint bolt connection node finite element model, wherein the finite element model determines the node yield mode judgment standard as follows: when the bamboo board hole is deformed for 0.05d, the pin groove bearing damage I occurs s The method comprises the steps of carrying out a first treatment on the surface of the If the hole of the bamboo plate is not displacedFailure is achieved but the bolt yields, a IIIm or IVm failure mode is considered to occur, wherein when a single hinge yielding III occurs in the recombined bamboo clapboards m When the double-hinge yield IV damage occurs to the interface of the recombined bamboo board and the steel plate, the double-hinge is formed in the recombined bamboo board and the interface of the recombined bamboo and the steel plate, and the method for establishing the finite element model of the bolt connection node of the recombined bamboo steel splint is as follows:
according to the multi-fold line model of pin groove bearing and pin bending stress-strain, a mark that the plastic deformation of 0.05d is generated by connection reaches the bearing capacity limit state is used as the basis, and a restructured bamboo steel splint bolt connection node finite element model is built according to the bearing capacity of a single bolt node and the displacement of the bolt node;
s3, correcting and verifying a node bearing capacity calculation mode according to the node bearing capacity result compared in the step S2 and the finite element model simulation result, outputting a node design of a steel splint bolt node, and expressing the corrected recombinant bamboo steel splint bolt connection bearing capacity formula as follows:
R k ＝K ad,min adf ha
K aⅠ ＝0.5
wherein R is k The standard value of the bearing capacity of the single bolt; phi is an adjustment coefficient, and the adjustment coefficient is taken according to the test proposal1.5.
2. The method for calculating the bearing capacity of the bolt connection node of the recombined bamboo-steel splint according to claim 1, wherein the node yielding mode in S1 comprises the bearing damage I of the recombined bamboo pin groove s Single hinge yielding III of bolt in recombined bamboo board m And the bolt generates double-hinge yield IV at the interface of the recombined bamboo board and the steel board.
3. The method for calculating the bearing capacity of the bolt connection node of the recombined bamboo-steel clamp plate according to claim 1, wherein the specific mode of the node design of the bolt node of the output steel clamp plate in the step S3 is as follows:
s31, preliminarily selecting a bolt with the diameter d, and determining Shan Shuanzhu bearing capacity R of the bolt according to a bearing capacity analysis model k ；
S32, determining the number of the studs according to a stress formula and setting the arrangement form of the studs on the basis of meeting the construction requirement;
s33, judging whether the stress resultant force of the bolts at the upper edge of the corner is smaller than or equal to the bearing force of a single bolt, and if so, outputting the determined diameter, number and arrangement form of the bolts;
and S34, if the combined force of the stress of the bolts at the upper edge of the corner is larger than the Shan Shuanzhu bearing force, judging whether the number of the bolts is consistent, if not, re-determining the number of the bolts and replacing the arrangement form, and if so, re-arranging the arrangement form.
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005035209A2 (en) * | 2003-07-03 | 2005-04-21 | Krishna Ram Datye | Wood bamboo composites |
| JP2012127077A (en) * | 2010-12-14 | 2012-07-05 | Jfe Steel Corp | Estimation method of bending load bearing capacity of composite girder |
| CN203200920U (en) * | 2013-03-05 | 2013-09-18 | 扬州工业职业技术学院 | Connection of beam column node of recombined bamboo frame structure |
| CN109610650A (en) * | 2018-11-23 | 2019-04-12 | 大连理工大学 | A kind of calculation method of steel pipe concrete column-steel beam punching bolt connection node anti-bending bearing capacity and moment-rotation relation |
| WO2021032906A1 (en) * | 2019-08-21 | 2021-02-25 | Lappeenrannan-Lahden Teknillinen Yliopisto Lut | A system and a method for monitoring material fatigue |
| CN113076585A (en) * | 2021-04-13 | 2021-07-06 | 中南林业科技大学 | Method for calculating pin bolt connection bearing capacity of wood structure steel clamping plate |
| CN214941637U (en) * | 2021-02-20 | 2021-11-30 | 东北林业大学 | Built-in vertical steel plate reinforcing reorganization bamboo roof beam |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20110151172A1 (en) * | 2008-08-22 | 2011-06-23 | Wansi Fu | Prestress structural material formed by reorganization with polygonal original bamboo and the manufacturing method |
-
2022
- 2022-07-19 CN CN202210846006.5A patent/CN115270327B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005035209A2 (en) * | 2003-07-03 | 2005-04-21 | Krishna Ram Datye | Wood bamboo composites |
| JP2012127077A (en) * | 2010-12-14 | 2012-07-05 | Jfe Steel Corp | Estimation method of bending load bearing capacity of composite girder |
| CN203200920U (en) * | 2013-03-05 | 2013-09-18 | 扬州工业职业技术学院 | Connection of beam column node of recombined bamboo frame structure |
| CN109610650A (en) * | 2018-11-23 | 2019-04-12 | 大连理工大学 | A kind of calculation method of steel pipe concrete column-steel beam punching bolt connection node anti-bending bearing capacity and moment-rotation relation |
| WO2020103234A1 (en) * | 2018-11-23 | 2020-05-28 | 大连理工大学 | Calculation method for flexural capacity and moment-rotation curve of concrete-filled steel tubular column-steel beam through bolt connecting joint |
| WO2021032906A1 (en) * | 2019-08-21 | 2021-02-25 | Lappeenrannan-Lahden Teknillinen Yliopisto Lut | A system and a method for monitoring material fatigue |
| CN214941637U (en) * | 2021-02-20 | 2021-11-30 | 东北林业大学 | Built-in vertical steel plate reinforcing reorganization bamboo roof beam |
| CN113076585A (en) * | 2021-04-13 | 2021-07-06 | 中南林业科技大学 | Method for calculating pin bolt connection bearing capacity of wood structure steel clamping plate |
Non-Patent Citations (1)
| Title |
|---|
| Experimental research on bearing capacity of the bolted PSB-steel-PSB joints;A Zhou 等;《journal of nanjing tech university》;全文 * |
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