Operationalising Minimum Force: The Need for Evidence

2020 ◽  
pp. 53-66
Author(s):  
Richard Evans ◽  
Clare Farmer
Keyword(s):  
Minimum Force

scholarly journals Static force characteristics of electromagnetic actuators for Braille screen

2011 ◽  
Vol 24 (2) ◽  
pp. 157-167 ◽  
Author(s):  
Ivan Yatchev ◽  
Krastio Hinov ◽  
Iosko Balabozov ◽  
Kristina Krasteva
Keyword(s):  
Magnetic Field ◽  
Finite Element Method ◽  
Finite Element ◽  
Permanent Magnet ◽  
Static Force ◽  
The Finite Element Method ◽  
Electromagnetic Actuators ◽  
Minimum Force ◽  
The Magnetic Field ◽  
Force Characteristics

Several constructions of electromagnetic actuators with moving permanent magnet for Braille screen are studied. All they are formed from a basic one that consists of two coils, core and moving permanent magnet. The finite element method is used for modeling of the magnetic field and for obtaining the electromagnetic force acting on the mover. The static force-stroke characteristics are obtained for four different constructions of the actuator. The constructions with ferromagnetic disc between the coils ensure greater force than the ones without disc and can reach the required minimum force.

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.

The Influence of the Fatigue Cycles Number on Material Hardness

2014 ◽  
Vol 658 ◽  
pp. 195-200
Author(s):  
Viorel Goanta
Keyword(s):  
Plastic Deformation ◽  
Indentation Load ◽  
The Other ◽  
Stress Cycle ◽  
Elastic Range ◽  
Maximum Value ◽  
Material Hardness ◽  
Stress Fatigue ◽  
Minimum Force ◽  
Maximum Minimum

In this paper we present the experimental results obtained after determining hardness on samples previously subjected to fatigue. Firstly, 6 identical samples have been subjected to stress fatigue in the elastic range a number of 105, 5∙105, 106, 2∙106, 3∙106 and 4∙106 cycles. For all samples we used the same form of stress cycle, respectively, sinusoidal, and the same values of maximum, minimum force and the amplitude of the cycle (50 kN, 30 kN and 10 kN). It is noted that the maximum value of the load was less than that at which samples fall within the plastic deformation. Therefore, the original loading of samples was performed in the elastic range. For each of the six samples determinations of levels of hardness were performed, with the value of indentation load of 10 kgf. Indentations were made on the samples, along the length of the calibration, at a distance of 10 mm one within the other. As it will be seen below, in the areas with the highest hardness were performed several indentations, in order to determine the highest hardness area, which, in our view, also presents the largest degree of plastic deformation.

Ground Reaction Forces in Children’s Gait

1989 ◽  
Vol 1 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Nancy L. Greer ◽  
Joseph Hamill ◽  
Kevin R. Campbell
Keyword(s):  
Sex Differences ◽  
Ground Reaction Force ◽  
Reaction Force ◽  
Ground Reaction Forces ◽  
Vertical Force ◽  
Reaction Forces ◽  
Braking Force ◽  
Force Components ◽  
Age Range ◽  
Minimum Force

Ground reaction force patterns during walking were observed in 18 children 3 and 4 years of age. The children walked barefoot at a self-chosen walking pace. Selected variables representing the vertical, anteroposterior, and mediolateral force components were evaluated. The results indicated that children in this age range contact the ground with greater vertical force measures relative to body mass than do adults. In addition, the minimum vertical force was lower, the transition from braking to propulsion occurred earlier, and the mediolateral force excursions were higher than typically found in adults. When the children were divided into groups on the basis of sex, differences were observed between those groups. The boys exhibited a greater difference in the vertical peak forces, a lower minimum force, a greater braking force, and a higher mediolateral force excursion value. The results indicated that children display a different ground reaction force pattern than do adults and that differences between boys and girls may be observed as early as ages 3 and 4 years.

Sign in / Sign up

Export Citation Format

Share Document