CN109885974A - It is a kind of with load initial point be damage starting point bearing capacity damage measurement method - Google Patents
It is a kind of with load initial point be damage starting point bearing capacity damage measurement method Download PDFInfo
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- CN109885974A CN109885974A CN201910221700.6A CN201910221700A CN109885974A CN 109885974 A CN109885974 A CN 109885974A CN 201910221700 A CN201910221700 A CN 201910221700A CN 109885974 A CN109885974 A CN 109885974A
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Abstract
It is the bearing capacity damage measurement method for damaging starting point that the invention discloses a kind of to load initial point, comprising the following steps: establishes skeleton curve according to load-displacement curve；Determine the initial slope K of skeleton curve1, the peak load P of skeleton curvem, the breakdown point (Δ of test specimenu, 0.85Pm), and the slope K for damaging straight line is determined according to breakdown point2；Determine that displacement is ΔiWhen characteristic value Pss、Pre；Impairment value D is determined according to damage calculation formulaP.The present invention loads resulting load-displacement curve using test, damages research to load initial point as damage starting point using bearing capacity as the Fundamentals of assessment damage status to structural earthquake and provides new method, new approaches.
Description
Technical field
The invention belongs to structural damage calculating field more particularly to it is a kind of with load initial point be damage starting point bearing capacity
Damage measurement technology.
Background technique
Since geological process will cause the damage of building structure, therefore building structure will be to it rear after being subjected to seismic Damage
Continuous bearing capacity and remaining life during one's term of military service generates significant impact.And damage measurement method of the structure under geological process
It is the theoretical basis of seismic design of structures, internal injury situation is the important evidence of structure shake post-reinforcing.Therefore, correct to grasp
Structure level of damage under geological process, and seek reasonable calculation method quantitative description structural elements under geological process
Degree of injury is of great significance for seismic design of structures and earthquake assessment.
Currently, damage measurement method has the disadvantage that 1) existing calculation method is complex；2) existing damage starting point
Definition do not met with actual conditions.
Summary of the invention
Goal of the invention: in view of the deficiencies of the prior art, the present invention is by uniting to the damage measurement method of building structure
Meter analysis, and summarize to existing damage measurement method advantage and disadvantage, it is based ultimately upon the deficiency of existing damage measurement method, is proposed
A kind of to load initial point is the bearing capacity damage measurement method for damaging starting point.
Technical solution: in order to solve the above technical problems, the present invention adopts the following technical scheme: one kind is to load initial point
Damage the bearing capacity damage measurement method of starting point, comprising the following steps:
Step 1) establishes skeleton curve；Test specimen is loaded, load-displacement curve is obtained；By the outer of load-displacement curve
Envelope is defined as the skeleton curve of test specimen；
Specifically: using first load control, the Protonation constant of rear Bit andits control, test specimen is added according to the Protonation constant
It carries, obtains load-displacement curve；The enveloping outer enclosure of load-displacement curve is defined as to the skeleton curve of test specimen, it is assumed that its function table
It is P=f (△ up to formulai), P is load, △iFor displacement.
Step 2) determines the initial slope of skeleton curve, and thus obtains the slope of not damaged straight line；Determine skeleton curve
Peak load Pm, determine the breakdown point of test specimen, and the slope K of damage straight line is determined according to breakdown point2；
Specifically: B point is the peak point of positive load, and corresponding load is i.e. positive peak load Pm；Load is from peak
It is worth load PmDrop to 0.85PmWhen corresponding C point (△u, 0.85Pm) it is the positive breakdown point loaded；If test specimen is not damaged, lotus
Carrying displacement curve will develop along the tangent line of load initial point O point, which is referred to as not damaged straight line；Assuming that positive load initial point
Tangent slope, that is, skeleton curve initial slope be k1, the function expression of not damaged straight line is P=k1△i；It is damage with O point
Hurt starting point, if loading to the test specimen destroyed completely, the load-displacement curve of test specimen will develop along straight line OC, claim the straight line
To damage straight line；Assuming that damage straight slope is k2, k2=0.85Pm/△u, so the function expression of damage straight line is P=k2
△i；The initial slope of negative sense skeleton curve, peak load, breakdown point and damage straight line slope and positive calculation method
It is identical.
Step 3) determines that displacement is ΔiWhen, test specimen is because of depression of bearing force value P caused by damagingssWith the test specimen phase
For damaging the bearing capacity remaining value P of terminalre；
Specifically: it is Δ that abscissa is taken on skeleton curveiA point E, cross E point make vertical line, with not damaged straight line OA hand over
In D point, F point is met at straight line OC, the x-axis coordinate of D, E and F point is △i；The length for remembering line segment DE is Pss=k1△i- f
(△i), the length of line segment EF is Pre=f (△i)-k2△i；Then for E point, PssIt is test specimen because being carried caused by damage
Power drop-out value, PreBearing capacity remaining value for this of test specimen relative to damage terminal；The value with forward direction load of negative sense load
It is identical；
Step 4) determines impairment value D according to damage calculation formulaP: O point is damage starting point, C point (△u, 0.85Pm) it is test specimen
Breakdown point is defined as damage terminal；Straight line OA is not damaged straight line；Straight line OC is damage straight line；So bearing capacity damage measurement
Formula is as follows:
The utility model has the advantages that
1. to load initial point as damage starting point, and the impairment value of breakdown point is the present invention is based on a skeleton curve
1, actual conditions are more in line with, solve the problems, such as that impairment value is not restrained in breakdown point；
2. providing a kind of new method the present invention is based on the decaying of bearing capacity for structural damage experimental study, it is suitable for knot
The case where damaging in the research of structure damage performance without the concern for circulation, is more suitable for component dullness loading condition.
Detailed description of the invention
Fig. 1 is the flow chart of the method for the present invention；
Fig. 2 is Protonation constant of the present invention；
Fig. 3 is load-displacement curve schematic diagram of the present invention；
Fig. 4 is skeleton curve schematic diagram of the present invention；
Fig. 5 is feature of present invention point and characteristic slope schematic diagram；
Fig. 6 is damage measurement method schematic diagram of the present invention.
Specific embodiment
As shown in Figure 1, a kind of to load the bearing capacity damage measurement method that initial point is damage starting point, this method is mainly wrapped
Include following steps:
Step 1) establishes skeleton curve；As shown in figs. 2 to 4, the skeleton curve is determined by load-displacement curve；
In shock test research, general using first load control, the Protonation constant of rear Bit andits control, Protonation constant is as shown in Figure 2.According to
The Protonation constant loads test specimen, and load-displacement curve as shown in Figure 3 can be obtained.In figure, P is load, and △ is displacement；Such as
Shown in Fig. 4, the enveloping outer enclosure of load-displacement curve is defined as to the skeleton curve of test specimen, it is assumed that its function expression is P=f
(△i)。
Step 2) is as shown in figure 5, determine the initial slope K of skeleton curve1, the peak load P of skeleton curvem, load is from peak
It is worth load PmDrop to 0.85PmWhen corresponding test specimen breakdown point (Δu, 0.85Pm), and damage straight line is determined according to breakdown point
Slope K2；As shown in figure 5, B point is the peak point of positive load, corresponding load is positive peak load Pm；C point (△u,
0.85Pm) it is the positive breakdown point loaded；If test specimen is not damaged, load-displacement curve will be along the tangent line of load initial point (O point)
Development, which is referred to as not damaged straight line (or linear elasticity straight line)；Assuming that tangent slope, that is, skeleton of positive load initial point is bent
The initial slope of line is k1, k1It can be can be calculated by METLAB software, so the function expression of the straight line is P=k1△i；With O
Point is damage starting point, if loading to the complete test specimen for destroying (impairment value 1), the load-displacement curve of test specimen will be along straight
Line OC development, the straight line are referred to as damage straight line.Assuming that damage straight slope is k2, k2=0.85Pm/△u, so damage straight line
Function expression is P=k2△i；Initial slope, peak load, breakdown point and the slope for damaging straight line of negative sense skeleton curve
It is identical as positive calculation method.
Step 3) is as shown in fig. 6, determine that displacement is ΔiWhen characteristic load Pss、Pre；Take the skeleton of positive load in Fig. 5
Curve simplifies as shown in Figure 6.Taking up an official post in skeleton curve takes abscissa for ΔiA point E, cross E point make vertical line, met at straight line OA
D point meets at F point with straight line OC, and the x-axis coordinate of D, E and F point is △i, as shown in Figure 6.The length for remembering line segment DE is Pss=k1
△i- f (△i), the length of line segment EF is Pre=f (△i)-k2△i.Then for E point, PssCause for test specimen because of damage
Depression of bearing force value, PreBearing capacity remaining value for this of test specimen relative to damage terminal.Negative sense load is loaded with forward direction
Value it is identical.
Step 4) determines impairment value D according to damage calculation formulaP.O point is damage starting point, C point (△u, 0.85Pm) it is test specimen
Breakdown point is defined as damage terminal.Straight line OA is not damaged straight line (or linear elasticity straight line)；Straight line OC is damage straight line；Curve
OBC is known as skeleton curve；So bearing capacity damage calculation formula is as follows:
Claims (5)
1. a kind of to load the bearing capacity damage measurement method that initial point is damage starting point, it is characterised in that: the following steps are included:
Step 1) establishes skeleton curve；Test specimen is loaded, load-displacement curve is obtained；By the external envelope of load-displacement curve
Line is defined as the skeleton curve of test specimen；
Step 2) determines the initial slope of skeleton curve, and thus obtains the slope of not damaged straight line；Determine the peak of skeleton curve
It is worth load Pm, determine the breakdown point of test specimen, and the slope K of damage straight line is determined according to breakdown point2；
Step 3) determines that displacement is ΔiWhen, test specimen is because of depression of bearing force value P caused by damagingssWith the test specimen point relative to
Damage the bearing capacity remaining value P of terminalre；
Step 4) determines impairment value D according to damage calculation formulaP: so bearing capacity damage calculation formula is as follows:
2. it is according to claim 1 a kind of to load the bearing capacity damage measurement method that initial point is damage starting point, it is special
Sign is: using first load control, the Protonation constant of rear Bit andits control in the step 1), according to the Protonation constant to test specimen into
Row load, obtains load-displacement curve；The enveloping outer enclosure of load-displacement curve is defined as to the skeleton curve of test specimen, it is assumed that its letter
Number expression formula is P=f (△i), P is load, △iFor displacement.
3. it is according to claim 2 a kind of to load the bearing capacity damage measurement method that initial point is damage starting point, it is special
Sign is: step 2) the damage straight line determines concrete mode are as follows: B point is the peak point of positive load, and corresponding load is i.e.
Positive peak load Pm；Load is from peak load PmDrop to 0.85PmWhen corresponding C point (△u, 0.85Pm) it is positive load
Breakdown point；It is damage starting point with O point, if loading to the test specimen destroyed completely, the load-displacement curve of test specimen is by edge
Straight line OC development, the straight line are referred to as damage straight line；Assuming that damage straight slope is k2, k2=0.85Pm/△u, so damage straight line
Function expression be P=k2△i；The initial slope of negative sense skeleton curve, peak load, breakdown point and damage straight line it is oblique
Rate is identical as positive calculation method.
4. it is according to claim 2 or 3 a kind of to load the bearing capacity damage measurement method that initial point is damage starting point,
Be characterized in that: the not damaged straight line of step 2) determines concrete mode are as follows: if test specimen is not damaged, load-displacement curve will be along load
The tangent line of initial point O point develops, which is referred to as not damaged straight line；Assuming that tangent slope, that is, skeleton of positive load initial point is bent
The initial slope of line is k1, the function expression of not damaged straight line is P=k1△i。
5. it is according to claim 4 a kind of to load the bearing capacity damage measurement method that initial point is damage starting point, it is special
Sign is: the step 3) Pss、PreIt is specific to determine method are as follows: it is Δ that abscissa is taken on skeleton curveiA point E, cross E point
Make vertical line, meet at D point with not damaged straight line OA, meets at F point with straight line OC, the x-axis coordinate of D, E and F point is △i；Remember line segment DE
Length be Pss=k1△i- f (△i), the length of line segment EF is Pre=f (△i)-k2△i；Then for E point, PssFor examination
Part is because of depression of bearing force value, P caused by damagingreBearing capacity remaining value for this of test specimen relative to damage terminal；Negative sense adds
What is carried is identical as the value of forward direction load.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107831069A (en) * | 2017-11-27 | 2018-03-23 | 中南大学 | A kind of method that elastic deformation energy at rock material peak load point is determined in Point Load Tests |
| CN107844622A (en) * | 2017-09-04 | 2018-03-27 | 湘潭大学 | A kind of simply supported beam damage recognition methods based on faulted condition uniform load face curvature |
| CN108920739A (en) * | 2018-04-27 | 2018-11-30 | 天津大学 | A kind of material constitutive model numerical analysis method considering damage cumulating effect |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107844622A (en) * | 2017-09-04 | 2018-03-27 | 湘潭大学 | A kind of simply supported beam damage recognition methods based on faulted condition uniform load face curvature |
| CN107831069A (en) * | 2017-11-27 | 2018-03-23 | 中南大学 | A kind of method that elastic deformation energy at rock material peak load point is determined in Point Load Tests |
| CN108920739A (en) * | 2018-04-27 | 2018-11-30 | 天津大学 | A kind of material constitutive model numerical analysis method considering damage cumulating effect |
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