CHAPTER # 4 COMPARISON OF SAP2000 AND EXPERIMENTAL RESULTS 4
CHAPTER # 4
COMPARISON OF SAP2000 AND EXPERIMENTAL RESULTS
4.1 SAP2000 RESULTS:
In the software, an incremental load of 2.5KN was applied starting from zero and the
displacement was recorded with respect to every incremental load. The values of load and corresponding displacement are shown in the Table 5.1.
4.2 EXPERIMENTAL RESULTS BY Mr Nouman MS Thesis:
4.2.1 EXPERIMENTAL SETUP:
Mr Nouman in his MS Thesis done experimental work on SCIP Panels by considering different cases. The panels were tested according to “Four Points Bending test” method. The experimental setup is shown in the figure 4.1. Starting from zero, Incremental load of 2.5KN was applied and the displacement corresponding to every incremental load was recorded, shown in the table 4.1
Figure 4.1: Experimental setup of SCIP Panel (Mr Nouman MS Thesis)
The data obtained through experiment work done by Mr Nouman is shown in the following table and a graph is also drawn to show the corresponding displacements under incremental load of 2.5KN starting from zero.
LOAD (KN) DISPLACEMENT (mm)
TABLE 4.1. DISPLACEMENT RESULTED FROM EXPERIMENT.
Figure 4.2: Load-displacement graph of Experimental results
4.2.2. Analysis of SCIP Using SAP2000.
Now using the same procedure including, material properties, panel dimension,loading condition ,the same panel is analysed in SAP2000, and under incremental load of 2.5KN starting from zero, the displacement values are given in the table and graph is drawn to show the difference between sap and experimental results.
Figure 4.3: Load applied to panel according to four point bending method.
Figure 4.4: Displacement contour of SCIP in SAP2000.
EXPERIMENT VALUE SAP RESULT
LOAD (KN) DISPLACEMENT (mm) DISPLACEMENT (mm)
0 0 0
2.5 1 0.052
5 1 0.084
7.5 1.5 0.119
10 2 0.154
12.5 2.5 0.182
15 4 0.21
17.5 7 0.245
20 9 0.28
22.5 15 0.315
25 23.88 0.35
Table 4.2: Load-displacement values of SAP2000 and experimental results for SCIP Panel
Figure 4.5: Load-displacement graph of Experimental and SAP results
From the above graph it is clearly seen that there is a lot of difference between experimental results and SAP2000 analysis results.In order to remove the difference in both results, we may apply some changes to the given data such as to imply the given loads and reduces the modulus of elasticity (E) and thickness to obtained higher displacement values to match the experimental results.
For load implication a constant value is consider which is 15, for which the SAP and experimental result got somewhat matched uto 12.5kn load which is the elastic limit, after that point the sap result shows constant variation while experimental results shows abrupt change in the displacement values. As shown in the tables and the graph.
EXPERIMENT VALUE SAP RESULTS SAP RESULTS
LOAD (KN) DISPLACEMENT (MM) DISPLACEMENT (MM) DISPLACEMENT (MM)
0 0 0 0
2.5 1 0.77 0.385
5 1 1.54 0.77
7.5 1.5 2.45 1.12
10 2 3.15 1.54
12.5 2.5 3.85 1.96
15 4 4.55 2.45
17.5 7 5.25 2.8
20 9 5.95 3.15
22.5 15 7 3.5
25 23.88 7.7 3.85
Table 4.3: Modified values of displacement in SAP2000.
Initially the thickness of the SCIP is reduced to half ,modulus of elasticity is also taken as half for all the three material used in SCIP.For this condition of half thickness and half modulus of elasticity load is implified by ten times and then implified by five times. The analysis result is shown in the above table and interpreted in the form of graph below.
Figure 4.6: Graph showing the modified displacement of SAP2000 vs experiment results.
From the graph it is indicated that upto linear limit which is upto 12.5KN load,there is somewhat closeness in the experimental and SAP results.After that there is a greater amount of change in displacement of experimental result as compared to SAP result.
From the different analysis over the SCIP, it comes to know that the reduction in the elasticity and thickness has less effect on the amount of displacement,only load greatly effect the displacement value.
For this we consider a case in which only load is amplified by a constant value of 15 under this all the values upto load 12.5KN matched with the experimental result.which is shown in the table below.
Amplified load. L*15
EXPERIMENT VALUE SAP RESULTS
LOAD (KN) DISPLACEMENT (MM) DISPLACEMENT (MM)
0 0 0
2.5 0.6 0.49
5 1 0.98
7.5 1.5 1.54
10 2 1.96
12.5 2.5 2.45
15 4 3.15
17.5 7 3.5
20 9 3.85
22.5 15 4.55
25 23.88 4.90
Table 4.4: Displacement values under the amplified loads.
Figure 4.7: Graph showing experimental and SAP results under implified load.
From the graph it is shown upto elastic limit sap and experimental results get matched but after that there is variation.
LOAD (KN) STRESS (KN/mm)
Table 4.5: Load-Stress values of SCIP Panel.
The graph of experimental results is a non-linear while that of SAP2000 is linear. The
Incremental loads show little displacement values in SAP as compared to experimental which show larger values of displacement. The linearity in SAP graph is remain existed even the materials used were assumed as non linear.Therefore it is not possible with SAP2000 to get the actual displacement values after the proportional limit is achieved while applying load.So upto elastic limit the SAP2000 and experimental displacement values somewhat get matched or near in values but after elastic point SAP2000 results is not real,which shows the limitation of this software application.In order to show the behavior of the graph like experimental, we must define some new software application for analysis and design of sandwich panels as well as for ordinary structures,In which non linearity of materials are pre defined.
CHAPTER # 5
CONCLUSIONS AND RECOMMENDATIONS
1. From practical point of view, SAP2000 is very easy and less time consuming to other softwares used in markets.
2. Load-displacement graph of SAP2000 shows that the stiffness values can be captured successfully.
3. SAP2000 gives linear graph and doesn’t show failure point, while the failure value in Experimental test is observed.
4. Load implification has greather effect on the values of displacement.
5. Displacement is less effected by appling variation in modulus of elasticity and thickness of SCIP Panels.
6. Upto elastic limit by applying amplified load the SAP and experimental results are get matched.
7. After elastic limit there is greater variation in both results because non linear behavior of materials is not defined in SAP2000.
1. Non-linearity of materials must be defined in order to show the behaviour of materials similar to experimental results of Mr Nouman. But SAP2000 software are unable to show the non linearity properties of material used,therefore a non linear based software must be introduced in the market for the analysis of nonlinear behavior shown in experimental results.
2. Material and geometric properties of materials used in SCIP must be studied before working them out.
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