Week 5: KNEX Process

This past week the group began constructing different KNEX trusses systems.  The group worked together to create several designs to test and learn from in order to create a better design.  These KNEX bridges are all 2'.  The final design will have to be 3'.  The group has not had any problems designing a strong bridge but the cost is on the high side in order to achieve a good cost/load ratio.  The group will look at ways to lower this ratio in the next weeks.

My views on the differences and similarities of the KNEX and WPBD have not really changed.  KNEX has the disadvantage of only 45degree increments and WPBD doesn't account for the horizontal forces applied to a bridge.  They both are great tools at looking into truss systems for bridges and testing them.

There are many differences between a KNEX bridge and a 20' steel bridge.  The different number of materials and different design possibilities are endless for a 20' steel bridge.  The KNEX bridges are limited to the few pieces given and to the 45degree joint increments.  The way the steel bridge joints are fastened at the gusset plates have huge variations in options as well.  The KNEX bridge does have a few advantages though.  The KNEX bridge can be tested and rebuilt without any cost.  A 20' steel bridge costs a lot of money to make and it must be right the first time.