Development of a novel combined system of deformation amplification and added stiffness and damping: Analytical result and full scale pseudo-dynamic tests

2016 ◽  
Vol 119 ◽  
pp. 61-80 ◽  
Author(s):  
Nicolás Tapia ◽  
José Almazán ◽  
Juan Baquero
Keyword(s):  
Full Scale ◽  
Dynamic Tests ◽  
Combined System ◽  
Analytical Result ◽  
Stiffness And Damping

scholarly journals A Novel Bio-Eco Technology Combined System for Rural Domestic Wastewater Treatment in a Tourism Area: A Full-Scale Study

2009 ◽  
Vol 26 (9) ◽  
pp. 1419-1427 ◽  
Author(s):  
Hanwen Liang ◽  
Junxin Liu ◽  
Xuesong Guo ◽  
Baoqing Shan ◽  
Jingzhu Zhao ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Domestic Wastewater ◽  
Full Scale ◽  
Combined System ◽  
Domestic Wastewater Treatment

Vibration exercise for treatment of osteoporosis: A theoretical model

2008 ◽  
Vol 222 (7) ◽  
pp. 1161-1166 ◽  
Author(s):  
M Aleyaasin ◽  
J J Harrigan
Keyword(s):  
Theoretical Model ◽  
Low Frequency ◽  
Bed Rest ◽  
Finite Amplitude ◽  
Time Varying ◽  
Vibration Exercise ◽  
Varying Coefficients ◽  
Low Frequency Vibration ◽  
Analytical Result ◽  
Stiffness And Damping

Orthopaedic rehabilitation of osteoporosis by muscle vibration exercise is investigated theoretically using Wolff's theory of strain-induced bone ‘remodelling’. The remodelling equation for finite amplitude vibration to be transmitted to the bone via muscle corresponds to a slowly time-varying non-linear dynamic system. This slowly time-varying system is governed by a Riccatti equation with rapidly varying coefficients that oscillate with the frequency of the applied vibration. An averaging technique is used to determine the effective force transmitted to the bone. This force is expressed in terms of the stiffness and damping parameters of the connected muscle. The analytical result predicts that, in order to obtain bone reinforcement, the frequency and amplitude of vibration should not exceed specified levels. Furthermore, low-frequency vibration does not stimulate the bone sufficiently to cause significant remodelling. The theoretical model herein confirms the clinical recommendations regarding vibration exercise and its effects on rehabilitation. In a numerical example, the model predicts that a femur with reduced bone mass as a result of bed rest will be healed completely by vibration consisting of an acceleration of 2 g applied at a frequency of 30 Hz over a period of 250 days.

Seismic Design and Hybrid Tests of a Full-Scale Three-Story Concentrically Braced Frame using In-Plane Buckling Braces

2013 ◽  
Vol 29 (3) ◽  
pp. 1043-1067 ◽  
Author(s):  
Ching-Yi Tsai ◽  
Keh-Chyuan Tsai ◽  
Pao-Chun Lin ◽  
Wai-Hang Ao ◽  
Charles W. Roeder ◽  
...  
Keyword(s):  
Seismic Design ◽  
Axial Strain ◽  
Local Buckling ◽  
Full Scale ◽  
Dynamic Tests ◽  
Braced Frame ◽  
Concentrically Braced Frame ◽  
Nonlinear Responses ◽  
Highly Nonlinear ◽  
Concentrically Braced

This research investigates the brace-to-gusset connection designs to allow the braces buckle in the plane (IP) of the frame. In order to study the performance of the IP buckling brace connections with different design details, five 3,026 mm–long A36 H 175 × 175 × 7.5 × 11 mm braces were tested using cyclically increasing axial displacements. All specimens failed at an average axial strain less than 0.025 due to the brace fracture at the mid-length where severe local buckling had occurred. Pseudo-dynamic tests on a three-story special concentrically braced frame (SCBF) using the proposed brace end connection details for six A36 H 150 × 150 × 7 × 10 mm braces were conducted using the PGA = 597 cm/s2 LA03 record to confirm with the component tests. The knife plates and IP buckling braces sustained a peak 0.049 rad interstory drift under the design base earthquake without fracture. The highly nonlinear responses were satisfactorily predicted by OpenSees. Recommendations on the seismic design of the IP buckling brace connections are provided.

scholarly journals State of the art of DSRW test equipment subjected to side loads and equipment proposal for static testing at natural scale

2019 ◽  
Vol 29 (2) ◽  
Author(s):  
Gram Rivas ◽  
Elliot Quispe ◽  
Sandra Santa Cruz
Keyword(s):  
Low Cost ◽  
Full Scale ◽  
Testing Equipment ◽  
Dynamic Tests ◽  
Static Test ◽  
Static Testing ◽  
Out Of Plane ◽  
Seismic Forces ◽  
Tilting Table ◽  
Full Scale Testing

Dry Stone retaining walls, DSRW, are low-cost traditional structures made of stones aimed to stabilize, support backfill and avoid soil erosion. They have massively been used as foundation of dwellings by vulnerable population located in the steeped hills surrounding some Latin-American cities. These walls are built following ancient techniques that are neither well studied nor formally established. Millions of people live in these conditions in seismic zones generating a high-risk situation. Experimental and numerical studies are needed in order to evaluate the reliability of low-cost DSRW and to validate or improve traditional techniques. The objective of this ongoing research is to design and construct a full-scale testing equipment to assess DSRW performance against lateral out-of-plane seismic forces. The methodology consists in the following steps: (1) Review of state-of-art of experimental testing of DSRW, (2) Analysis of failure modes of similar constructions (3) Conceptual and structural design of optimum full-scale testing equipment, (4) Construction planning (blueprints and budget) and (5) Construction and operation. Testing equipment found in technical literature can be classified into two groups according to the applied force: dynamic and static. Forces in dynamic tests are the result of acceleration imposed to the specimen, e.g. shaking tables and centrifuge machines. Forces in static testing are applied by hydrostatic pressure, lateral earth pressure, and specimen´s weight. Applied forces in dynamic tests simulate seismic forces well. On the other hand, it is a high cost solution and requires very specialized staff for operation and maintenance. Static alternatives are more affordable but seismic forces are roughly simulated by static forces. In this work a tilt table is proposed to test full-scale specimens. In this test, the specimen is built in a horizontal table that is slowly rotated.  In this way, a static out-of-plane force acts in each particle of the specimen. The magnitude of the total force is the specimen´s weight multiplied by the sin of the rotating angle. Static test results could be conservative but they could give a good approach to understand DSRW damage accumulation process and failure. Two equipments were proposed: (1) tilting table for monotonic static test and (2) tilting table for cylic test. We compare costs, required area, construction feasibility, and operation manageability. We conclude that both of them are straightforward solutions to assess DSRW performance against out-of-plane lateral forces.

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