Numerical Investigation on the Pull-Out Behaviour of Suction Caissons in Clay

2006 ◽  
Author(s):  
Mostafa Zeinoddini ◽  
Mahmood Nabipour
Keyword(s):  
Aspect Ratio ◽  
Numerical Investigation ◽  
Production Systems ◽  
Friction Angle ◽  
Critical Issue ◽  
Order Effect ◽  
Offshore Structures ◽  
Pull Out ◽  
Soil Cohesion ◽  
Suction Caissons

Since their inception suction caisson foundations have presented themselves as proven means of anchoring floating production systems and fixed offshore structures. The pull-out capacity of suction caissons remains a critical issue in their applications, and in order to produce effective designs, reliable methods of predicting the capacity are required. In this paper results from a numerical investigation on the behaviour of the suction caissons in clays against pull-out loading have been presented. Soil nonlinearities, soil/caisson interactions and the effects from the suction on the behaviour have been taken into account. A linear relationship has been observed between the soil cohesion values and the pull-out capacity. Under drained conditions, beyond specific limits of soil cohesion values, the increase in the cohesion value have found to demonstrate no further influence on the pull-out capacity. The soil internal friction angle has been noticed to have an exponential increasing effect on the pull-out capacity. With constant values of the caisson diameter, an increase in the aspect ratio noticed to have a second order effect of the friction originated part and a linear influence on the cohesion originated part of the resistance. With constant values of the caisson length, an increase in the aspect ratio values has found to result in an exponential decrease of the pull-out capacity. Based on the obtained numerical results simple formulations and approximations have been proposed in order to estimate the effects of the studied parameters on the pull-out capacities.

Numerical Investigation Into Parameters Influencing the Installation of Suction Caissons in Sand

2008 ◽  
Author(s):  
Mostafa Zeinoddini ◽  
Woorya H. Shariati ◽  
Mahmood Nabipour
Keyword(s):  
Numerical Investigation ◽  
Friction Angle ◽  
Order Effect ◽  
Reduction Factor ◽  
Second Order ◽  
Strength Reduction Factor ◽  
Dilatancy Angle ◽  
Linear Effect ◽  
Full Penetration ◽  
Suction Caissons

This paper reports results from a numerical investigation into the suction caissons penetration in sand. Two dimensional axisymmetric models have first been calibrated and verified against several laboratory and field test data from other researchers. Soil nonlinearities and soil/caisson interactions have been taken into account. The verified models have then been used to evaluate the effects from various soil/structure characteristics on the performance of the suction caissons during the installation phase in sand. The results of the current study show that the total installation force required for the full penetration of the caisson has a second order relationship with the soil/caisson interface strength reduction factor. The soil cohesion has also been found to have a second order effect on the total installation force. The soil internal friction angle, and the soil modulus of elasticity have each been noticed to present an increasing linear effect on the total installation force. It has also been observed that while the caisson diameter remains constant, with an increase in the caisson length the total installation force almost linearly increases. This is the same when the caisson length is kept constant but its diameter increases. Dilatancy angle and Poisson’s ratio have been realized to have a second order monotically increasing effect on the total installation force.

Failure Modes of Tapered Suction Caissons Under Vertical Pull-Out Loads

2007 ◽  
Author(s):  
Mahmood Nabipour ◽  
Mostafa Zeinoddini ◽  
Mahmood R. Abdi
Keyword(s):  
Failure Modes ◽  
Numerical Approach ◽  
Local Failure ◽  
Superior Performance ◽  
Soil Plug ◽  
Pull Out ◽  
Modes Of Failure ◽  
Numerical Studies ◽  
Second Mode ◽  
Suction Caissons

The pull-out performance of conventional upright suction caissons has been investigated by different researchers. However, no attention has been formerly paid to tapered suction caissons. Some numerical studies already conducted by the authors demonstrated that tapered caissons exhibit pull-out capacities well above than that from their corresponding upright caissons. This paper deals with different failure mechanisms of tapered suction caissons and discusses some reason for their superior performance. A numerical approach has been used and different combinations of caisson types/ soil categories have been examined. With tapered suction caissons two different modes of failure have been discerned. The first mode has been noticed to develop in weak clays and sands under drained conditions. This mode corresponds to a shear sliding failure in the soil plug along the caisson’s interior wall. Concurrently a soil wedge is formed in the soil body adjacent to the caisson. The second mode of failure has been observed in higher strength drained clays and undrained clays and sands. With this failure mode a local failure at the bottom of the soil plug has been noticed to happen. At the same time the failure is extended to the lower surfaces of a soil wedge outside of the caisson. The detached soil plug accompanies the caisson in its movement upward following the local failure.

Experimental measurements of the shear force on surface mount components simulating the wave soldering process

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Violeta Carvalho ◽  
Bruno Arcipreste ◽  
Delfim Soares ◽  
Luís Ribas ◽  
Nelson Rodrigues ◽  
...  
Keyword(s):  
Printed Circuit Boards ◽  
Deep Understanding ◽  
Critical Issue ◽  
Circuit Boards ◽  
Content Type ◽  
Surface Mount ◽  
Soldering Process ◽  
Wave Soldering ◽  
Pull Out ◽  
Minimum Force

Purpose This study aims to determine the minimum force required to pull out a surface mount component in printed circuit boards (PCBs) during the wave soldering process through both experimental and numerical procedures. Design/methodology/approach An efficient experimental technique was proposed to determine the minimum force required to pull out a surface mount component in PCBs during the wave soldering process. Findings The results showed that the pullout force is approximately 0.4 N. Comparing this value with the simulated force exerted by the solder wave on the component ( ≅ 0.001158 N), it can be concluded that the solder wave does not exert sufficient force to remove a component. Originality/value This study provides a deep understanding of the wave soldering process regarding the component pullout, a critical issue that usually occurs in the microelectronics industry during this soldering process. By applying both accurate experimental and numerical approaches, this study showed that more tests are needed to evaluate the main cause of this problem, as well as new insights were provided into the depositing process of glue dots on PCBs.

scholarly journals Inverse distance weighting interpolated soil properties and their related landslide occurrences

2018 ◽  
Vol 195 ◽  
pp. 03013 ◽  
Author(s):  
Purwanto B. Santoso ◽  
Yanto ◽  
Arwan Apriyono ◽  
Rani Suryani
Keyword(s):  
Internal Friction ◽  
Slope Stability ◽  
Soil Properties ◽  
Hard Rock ◽  
Friction Angle ◽  
Inverse Distance Weighting ◽  
Central Java ◽  
Soil Cohesion ◽  
Distance Weighting ◽  
Inverse Distance

The causes of landslides can be categorized into three factors: climate, topographic, and soil properties. In many cases, thematic maps of landslide hazards do not involve slope stability analyses to predict the region of potential landslide risks. Slope stability calculation is required to determine the safety factor of a slope. The calculation of slope stability requires the soil properties, such as soil cohesion, the internal friction angle and the depth of hard-rock. The soil properties obtained from the field and laboratory investigation from the western part of Central Java were interpolated using Inverse Distance Weighting (IDW) to estimate the unknown soil properties in the gridded area. In this research, the IDW optimum parameter was determined by validation toward the percent bias. It was found that the IDW interpolation using higher weighting factor corresponds with a higher percent bias in case of the depth of hard-rock and soil cohesion, while the opposite was found for the internal friction angle. Validation to landslide incidents in western parts of Central Java shows that the majority of landslide incidents occur at depths of hard rock of 6 m-8 m, at soil cohesions of 0.0 kg/cm2-0.2 kg/cm2, and at internal friction angles of 30°-40°.

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