Numerical and theoretical studies on cold-formed steel unlipped channels
               subjected to axial compression

This paper presents both the analytical and theoretical investigations on ultimate load carrying capacity and behaviour of CFS unlipped channels with their ends fixed and subjected to axial compression. The numerical studies have been carried out in the elastic as well as in the plastic ranges of loading. The slenderness ratio of the channels chosen is 40, 80,100 and 120. Three different web depths [shallow, medium and deep] with five thicknesses have been chosen. In addition to the numerical studies, comparison with the design strengths predicted by using North American Standards for CFS structures. It is observed that the design strength predicted by the specifications are conservative for axially loaded columns. In the present investigation, an attempt is made to study the ultimate load carrying capacity and the mode of failure. Load versus axial shortening behaviour has been studied for various slenderness ratios for a few specimens.

Cold-formed Steel; Buckling; Axial compression; Unlipped channel; Finite element analysis; Codal provisions

Authorship

G. Beulah Gnana Ananthi ^**Author email: beulahsap@gmail.com

Assistant Professor, Department of Architecture, SAP Campus, Anna University, Chennai - 600025, IndiaAnna UniversityIndiaChennai, IndiaAssistant Professor, Department of Architecture, SAP Campus, Anna University, Chennai - 600025, India

G. S. Palani

Sr. Principal Scientist, CSIR-Structural Engineering Research Centre, CSIR Road, Taramani, Chennai- 600113, IndiaStructural Engineering Research CentreIndiaTaramani, Chennai, IndiaSr. Principal Scientist, CSIR-Structural Engineering Research Centre, CSIR Road, Taramani, Chennai- 600113, India

Nagesh R. Iyer

Director, CSIR-Structural Engineering Research Centre, CSIR Road, Taramani, Chennai- 600113, IndiaStructural Engineering Research CentreIndiaTaramani, Chennai, IndiaDirector, CSIR-Structural Engineering Research Centre, CSIR Road, Taramani, Chennai- 600113, India

*Author email: beulahsap@gmail.com

SCIMAGO INSTITUTIONS RANKINGS

Figures | Tables

Figures (10)
Tables (7)

Young's Modulus (E) (MPa)	Yield Stress (F_y) (Mpa)	Ultimate Stress (F_u) (Mpa)	F_u/F_y	Percentage Elongation
196	186	319.06	1.72	18.7

Specimen	P_EXP (kN)	P_FEA (kN)	P_EXP/ P_FEA
CFC 40x20x2.1	58.29	57.93	1.01
CFC 60x30x2.1	73.42	80.92	0.91
CFC 80x40x3.3	112.1	97.8	1.15
CFC 100x50x3.3	135.7	135.68	1.00
Mean			1.01
Standard Deviation			0.08

S. No	Sections	λ	P_FEA	P_NAS/P_FEA
1	CFC 100x50x1.25 mm	40	29.39	0.86
		80	21.81	0.79
		100	19.88	0.79
		120	15.53	0.78
2	CFC 100x50x1.6 mm	40	43.76	0.80
		80	35.74	0.92
		100	24.72	0.95
		120	20.86	0.84
3	CFC 100x50x2 mm	40	57.59	0.88
		80	54.62	0.66
		100	48.15	0.67
		120	39.89	0.61
4	CFC 100x50x2.55 mm	40	93.00	0.75
		80	88.25	0.57
		100	77.06	0.58
		120	65.22	0.51
5	CFC 100x50x3.15 mm	40	114.4	0.78
		80	111.6	0.56
		100	101.5	0.58
		120	70.83	0.62
			Mean	0.78
			Standard Deviation	0.09

S.No	Specimen Identity	Experimental Ultimate Load P_Exp (kN)	Predicted Ultimate Load P_NAS (kN)	Proposed Ultimate Load (P^*FEA)	P^*FEA /P_NAS	P*FEA /P_Exp
1	P36F0280	65.00	57.78	75.69	1.31	1.16
2	P36F1000	59.00	48.54	63.59	1.31	1.08
3	P36F1500	50.10	38.42	50.33	1.31	1.00
4	P36F2000	41.70	30.03	39.34	1.31	0.94
5	P36F2500	32.80	22.67	29.70	1.31	0.91
6	P36F3000	24.70	17.80	23.32	1.31	0.94
				Mean	1.31	1.01

S. No	Sections	λ	P_FEA	P_NAS/P_FEA
1	CFC 150x50x1.25 mm	40	29.54	0.82
		80	26.11	0.78
		100	19.18	0.93
		120	18.18	0.83
2	CFC 150x50x1.6 mm	40	43.73	0.87
		80	39.75	0.80
		100	39.61	0.70
		120	29.95	0.78
3	CFC 150x50x2 mm	40	67.19	0.84
		80	63.26	0.82
		100	55.16	0.79
		120	44.07	0.84
4	CFC 150x50x2.55 mm	40	96.32	0.88
		80	91.24	0.79
		100	75.62	0.81
		120	69.67	0.83
5	CFC 150x50x3.15 mm	40	141.47	0.82
		80	123.61	0.71
		100	103.91	0.70
		120	72.26	0.80
			Mean	0.80
			Standard Deviation	0.07

S. No	Sections	λ	P_FEA	P_NAS/P_FEA
1	CFC 200x50x1.25 mm	40	30.74	0.82
		80	29.54	0.74
		100	27.34	0.71
		120	22.73	0.75
2	CFC 200x50x1.6 mm	40	44.32	0.89
		80	43.42	0.78
		100	41.16	0.74
		120	36.62	0.72
3	CFC 200x50x2 mm	40	68.06	0.87
		80	65.4	0.77
		100	61.91	0.73
		120	54.42	0.78
4	CFC 200x50x2.55 mm	40	109.75	0.83
		80	103.88	0.74
		100	100.86	0.67
		120	91.63	0.62
5	CFC 200x50x3.15 mm	40	172.55	0.84
		80	164.5	0.72
		100	154.63	0.70
		120	125.61	0.69
			Mean	0.76
			Standard Deviation	0.09